building green in new zealand: wood, a sustainable construction choice

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Wood — A SustainableWood — A SustainableWood — A SustainableWood — A SustainableWood — A Sustainable

Construction ChoiceConstruction ChoiceConstruction ChoiceConstruction ChoiceConstruction Choice

Mike Collins, Tim Barnard, Karen Bayne,Angela Duignan, and Sigrid Shayer

Forest Research Bulletin No.226

Forest ResearchRotorua, New Zealand

2003

2 Building Green

Editor: Judy Griffith

Photographer: Jonathan Barran PhotographyCover Design: Creative Department, Tauranga

Printer: Forest Research CopyCentre

DISCLAIMER

In producing this Bulletin reasonable care has beentaken to ensure that all statements represent the bestinformation available. However, the contents of thispublication are not intended to be a substitute forspecific specialist advice on any matter and shouldnot be relied on for that purpose.

NEW ZEALAND FOREST RESEARCH INSTITUTELIMITED and its employees shall not be liable onany ground for any loss, damage, or liability incurredas a direct or indirect result of any reliance by anyperson upon information contained or opinionsexpressed in this work.

To obtain further copies of this publication, or for information about Forest Research publications,please contact:

Publications OfficerForest Research telephone: +64 7 343 5899Private Bag 3020 facsimile: +64 7 343 5379Rotorua e-mail: [email protected] Zealand website: www.forestresearch.co.nz

ISSN 1174-5096

© Copyright New Zealand Forest Research Institute Limited 2003

All rights reserved. Unless permitted by contract or law, no part of this work may be reproduced, stored,or copied in any form or by any means without the express permission of the NEW ZEALAND FORESTRESEARCH INSTITUTE LIMITED.

National Library of New Zealand Cataloguing-in-Publication Data

Building green in New Zealand: Wood — a sustainable construction choice /Mike Collins … [et al.].(Forest Research Bulletin (Rotorua, N.Z.) ; No. 226)Includes bibliographical references.1. Building, Wooden—Environmental aspects—New Zealand. 2. Wood—Utilisation—New Zealand. 3. Sustainable architecture—New Zealand.I.␣ Collins, M. J. (Michael John), 1942– II. New Zealand Forest ResearchInstitute. III. Series694.0993—dc 21

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Foreword

According to the United Nations, the battle forsustainable development will be won or lost in theworld’s cities. Most of the global population, including85% of New Zealanders, live in urban areas. Our goalis to have liveable cities that support social well-being,quality of life, and cultural identities, and cities thatare centres of innovation and economic growth.

The built environment is what makes a city. Buildingsare long-term assets not just for the people who ownthem, but also for the cities and towns where they arelocated. Buildings are significant users of energy —13% is consumed by residential users and 9% bycommercial buildings. It is the Government’s objectiveto achieve best practice energy performance in newresidential and commercial buildings.

All of this means that it is very important for architects,building industry professionals, property developers,and home owners to make informed decisions aboutthe design and materials to be used in New Zealandbuildings.

While timber houses have long been a defining featureof the New Zealand built environment, in recent yearswe have seen a move to a wider range of buildingmaterials. Forest Research believes that timber couldbe a preferred building material for the future,contributing to a sustainable approach to construction.

I hope that this Bulletin will encourage buildingindustry professionals and their customers to focus onthe sustainability of building designs and materials —the contribution to household energy efficiency, effectson human health, landscape and aesthetic values, andthe economic opportunities and challenges arising fromharvesting New Zealand’s “wall of wood”. It is timefor sustainability to become something that we do,rather than something that we talk about.

Hon. Marian L. HobbsMinister for the EnvironmentMinister with Responsibility for Urban Affairs

Foreword

4 Building Green

Acknowledgments

This Bulletin has evolved from work carried out underthe Built Environment research programme at ForestResearch, funded by Government’s Foundation forScience, Research and Technology (FRST)programme.

We are indebted to the following people for their time,contributions, and assistance in the preparation of thisdocument:

Kevin Hanvey; Gaia Architects; James Lunday;Kevin McBride; Roman Jaques; Lawrie Halkett;Kevin Golding; Jonathan Barran; TeresaMcConchie; Claire Benge; Graeme North; RobertVale; Chris Vincent; Peter Sewell; SpencerNicholls; John Prebble; Mark Batchelor; AlanDrayton; Murray Parrish; Kevin Grimes; RuthWilkie; David Turner; Grant Rosoman; PeterWilson; Grant Emms.

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Contents

Foreword 3

Acknowledgments 4

Preface 7

Introduction 9

Sustainable Development Policy—NewZealand and Overseas 10

Concept 10

Landmarks in Sustainable UrbanDevelopment 10

Policy and Cultural Changes 12International 12New Zealand 12

A Unique Cultural Perspective onSustainability 13Role for Timber in New Zealand PolicyChanges 13

New Zealand Legislation and Policy 15The Resource Management Act 1991 15The New Zealand Building Code 15Local Government Bill 2002 16Climate Change Foundation Policies16

Putting Policy into Practice in New Zealand—Some Territorial Authority Initiatives 16

Waitakere City Council 16Sustainable Home Guidelines 16The Better Building Code 17

Learning From Others—Some OverseasLocal Authority Initiatives 18

South Somerset District Council andSomerset County Council, UK 18

City of Portland, Oregon, USA 18

Wood in the Sustainably BuiltEnvironment 20

Wood Construction and Climate Change 20Effect of Climate Change on the BuiltEnvironment 20

Changing Climates—Changing Homes 20Reducing Carbon Emissions by UsingWood 21

Carbon neutrality of wood 21Energy efficiency of wood 22

Current and Traditional Trends of WoodUse in the Building Sector 22

Sustainable Building—Some Definitions 23Ministry for the Environment (MfE) 23Building Research Association of NewZealand (BRANZ) 24

Ecospecifier 24

Holistic Approach to Sustainability 25Low Impact 25Passive Design 26Pleasant Atmosphere 26

Building With Wood—Engineering Aspectsand Life-cycle Analysis 26

Structural Performance 27Strength and Stiffness 27Wind and Earthquake Resistance 27Load-sharing 28Fire Resistance 28

Thermal and Acoustic Performance 29Thermal Design 29Acoustic Design 30

Aesthetic Considerations 31Value and Image 31Architectural Awareness 31

Durability and Maintenance of WoodenStructures 32

Moisture Design 32Maintenance 33Preservative Treatment 34Mould and Decay in New Zealand Houses 35Achieving Durability through Treatment 35H1 Plus Concept 36Weighing up the Risks of Treatment 36

Environmental Performance 39Embodied Energy 39Life-cycle Analysis (LCA) 40Waste Minimisation 41

Built Green: From Vision to Reality 44

Public Buildings 44Glencoe Visitor Facilities, Scotland 44Primary School, Notley Green, Essex 45Stenurten Kindergarten, Copenhagen 46

Commercial Buildings 47Punakaiki Eco Resort, South Island, NewZealand 47

Eastwood Road Clinic, Remuera, Auckland,New Zealand 48

Green on the Grand (Office Building),Ontario, Canada 50

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Finishes and furnishings 50Omicron Consulting, Office Development,Canada 51

Large Commercial Buildings 51Olympic Exhibition Centre, Sydney, NSW,Australia 51

Structural description 51

Residential Housing 52Co-operative Housing Association ofAotearoa/New Zealand (CHAANZ) 52

Van Midden House—An “Affordable”House, Scotland 53

Affordable Low-energy Houses in Lindas,Goteborg, Sweden 54

Conclusions 56

Appendices 57

Appendix 1: Enhancing the Profile of Wood 57Promotion of Wood 57New Zealand 57Wood for Good 57Be Constructive! 57

Appendix 2: Obstacles to the SustainableUse of Wood in Construction 58

Environmental Impacts of Wood as aBuilding Material 58

Popular Misconceptions 58Availability of Sustainably Produced Timber58Fire 58

Decay 58Wood Quality 59Building Industry 59Timber Industry 59

Appendix 3: Life-cycle Assessment Systems 60BREEAM 60LEED 60Ecospecifier 60Ecoscan 60ATHENA 60Assessment Systems 60

Appendix 4: Sustainable Forestry and theEnvironment 61

New Zealand’s Plantation Forests 61Regional Development 61Supply 61Forest Certification 61Future Forests 62Renewable Energy from Biofuels 62

Appendix 5: Weblinks 63New Zealand 63Australia 63UK 63USA 63Canada 64Other International 64

References 65

Glossary 68

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Preface

For more than 30 years national and local governments,private enterprise, non-governmental organisations,and local communities have sought to establish aframework for sustainable development. Manyarchitects, local governments, and building firms areincorporating the sustainability agenda (Agenda 21)into their practices and it is now a growing trend,particularly in North America and Europe.

The incorporation of sustainable developmentprinciples and practices within public and private sectororganisations in New Zealand is somewhat behind thatof international standards. However, recent legislationshows that the support for sustainable development isgrowing, and highlights the awareness at national levelof the need to incorporate stronger sustainabilityprinciples into policy development.

The Local Government Bill allows local governmentmore autonomy to act on a range of sustainabilityissues. The Resource Management Act (RMA)promotes the sustainable management of natural andphysical resources and, although not a planning act,does offer sufficient scope to justify the considerationof sustainability in the built environment. The NewZealand building code also incorporates aspects ofsustainability, and is performance-based rather thanprescriptive.

The timing for the New Zealand construction sectorto take seriously the principles of sustainable buildingis also good from a political sense due to the release ofthe Government’s Preferred Policy package, giving thestrategy for implementation should Kyoto be ratified.The Rio+10 World Summit in Johannesburg duringSeptember 2002 has been a stimulus for renewedGovernment thinking, and a National SustainableDevelopment strategy will attempt to achieve policyintegration across both central and local government.

New Zealand is a net exporter of wood products witha harvest expected to reach 30 million m3 by 2006,providing opportunities for new employment andprocessing, as well as value-added exportopportunities. While Pinus radiata will continue to bethe major plantation species, attention is also beinggiven to other species and their potential for specificsites and uses.

New Zealand’s plantations have a much wider role toplay in our communities than simply wood production,employment, and wealth creation. Trees are also useful

carbon sinks, and they can be used for recreationalneeds and to conserve soil.

Issues regarding the use of illegal logging practicesand the unsustainable long-term harvesting of old-growth timber have seen many export timbers comeunder close scrutiny. In contrast, New Zealand’splanted forests are sustainably managed, and areamongst the most intensively studied and monitoredin the world. The ability to detect changes easily meansthat many of the worst impacts may be avoided ormitigated before environmental problems are created.

Global warming from greenhouse gas emissions iscausing world-wide climate change with rising sealevels and a greater incidence of storms, droughts, andfloods. The effects of climate change in New Zealandover the next 50–100 years will be significant, giventhat we are a low-lying country, with wide-rangingweather patterns. Building with wood, however, canhelp reduce the total carbon emissions from thebuilding sector. Wood products release carbon that wasabsorbed during growth and are therefore carbonneutral. Emission reductions can occur at all stages inthe building’s lifetime through the choice of rawmaterial, construction process, service requirements(heating and lighting), demolition, and disposal.

The manufacturing of wood products uses considerablyless energy than the manufacturing of products fromalternative competing materials. Several Life CycleAnalyses from around the world have assessed theenvironmental performance of wood, finding it to bean environmentally friendly building material whichreleased fewer air- and water-borne contaminants thanmetal and concrete. A 17% increase in wood usage inthe building industry could result in a 1.5% reductionof total energy consumed in New Zealand. Thisrepresents a 20% reduction in carbon emissions fromthe manufacture of all building materials.

Wood has a strong history of use for construction inNew Zealand since the arrival of Maori and, later,European settlers. Timber frame construction continuesas the predominant form of housing construction inAustralasia and, as a result of this expertise, timber-framed houses are relatively cheap to construct, quickto erect, and simple to modify. A sizeable culture andindustry have been developed around this buildingtechnology.

The other main use of wood is in providing energy,both for industry and home heating. Energy derived

Preface

8 Building Green

Wood, compared to alternative construction materials, isthe first choice for those looking for a sustainableapproach to construction, as well as a cost-effective andreliable product. For timber to be viewed as the preferredmaterial for the future, the built environment sector’sunderstanding of the qualities of timber and woodproducts that contribute to a sustainable environment,needs to increase. When the synergies and interactionsof wood with other materials in building design areproperly understood and implemented, true sustainableconstruction can begin to be realised.

from wood-processing residues (bioenergy) providesaround 6% of New Zealand’s consumer energy.Bioenergy has a competitive advantage over other fuelsin providing low-temperature heat. It can easilysubstitute for fossil fuels such as natural gas, oil, andcoal, and for electricity, when these are used for energypurposes such as space heating and hot water heating.

Construction waste usually exceeds municipal wasteon a weight per capita basis in most western cities, buteconomical and environmental pressures are nowforcing a change in waste disposal. Prefabrication offrames and trusses offsite, as well as the factoryproduction of fingerjointed products, has reduced thenumber of small wooden off-cuts produced, anddeconstruction, rather than demolition, allows woodenbuilding materials to be salvaged for recycling or reuse.

Our understanding of sustainable buildings iscontinually developing. A building which is designedusing sustainable principles will enhance, but have verylittle impact on, the environment. Passive indoorclimate design can keep the living environmentcomfortable with reduced energy consumption. Intimber structures, thermal capacity may be deliberatelyincreased where it is most effective, by incorporatingother materials, and minimised where it is leastdesirable. Engineering principles, including layout andorientation of rooms, windows, and overhangs, andthe thermal properties of the materials used for thestructure, claddings, windows, and insulation can beused to ensure that buildings are warm in winter andcool in summer.

The atmosphere of a building can give an emotivefeeling to the dweller, and studies have shown wood,used in interior décor, draws positive emotionalresponses. In the end, all internal climates arecompromises and most requirements can be meteconomically and within acceptable limits with theflexibility of design, construction, and operationoffered by timber buildings.

The risk of loss of life in a wooden building is nogreater, and may be less, than the risk in a non-woodbuilding. Heavy timber construction has a well provenresistance to intense fires. This is in contrast to metalbeams which have been known to melt and lose allstrength in conditions where heavy wooden beamshave lost only a small proportion of their originalstrength.

Compared with other materials, solid timber beamshave relatively high strength for their stiffness, andtimber frame construction has a particularly goodreputation for earthquake resistance due to a favourablecombination of light structure weight and ductilejointing systems. The light weight of wood buildingsplaces less demand on foundation systems and enablesbuildings to be built with less ground disturbance.

Moisture control and regular maintenance are the keysto long life of any building and this is particularly thecase with wooden buildings. Wood does not deterioratewith age alone, but is subject to insect and fungal attackif the moisture content is in a suitable range. Controlof moisture is achieved initially by careful design andconstruction of the building, followed by appropriateuse and good maintenance. Well designed andmaintained buildings in wood have an indefinite life,limited more by obsolescence than deterioration of thebuilding fabric. At the end of its useful life, a woodenbuilding may be easily modified, upgraded,deconstructed, or moved to a new location to start lifeanew.

While there are obvious environmental advantages inusing wood products for building, the use of wood alsoneeds to be seen in the context of overall aesthetics,landscape, and culture, as well as individualpreferences, human health, costs, and functionality.Sustainable construction incorporates much more thansimply embodied energy of materials, and should beaddressed holistically for the life of the building.

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Introduction

The built environment is for most of us the place wherewe live, work, and play. More than eight out of 10New Zealanders live in urban or suburbanenvironments; consequently, the way we choose tomanage our cities and suburbs and construct ourbuildings today has an impact on the quality of theenvironment our children will enjoy tomorrow.

Huge amounts of resources and energy are tied upwithin our cities and their buildings. If we are tomanage these resources more efficiently andsustainably we need to:

• Learn from best practice from around the world

• Build on our strengths and natural advantages

• Apply common sense and practical solutions

• Share our experience and knowledge with eachother.

This Bulletin provides information for planners,architects, and those with an interest in urban planningand design. The Bulletin is particularly aimed at:

(a) Those who are involved in central and localpolicy-making for sustainable urban development,for whom the sections around policy developmentand changing climates are most useful;

(b) Building designers and specifiers, for whom thesections around achieving sustainable buildingdesign through the use of wood are most useful.

In this Bulletin we address sustainability issues in ourbuildings and homes and future policies, allowingpractitioners in the building professions to take furthersteps towards a more sustainable approach to building.It is clear that sustainability in the urban environmentwill soon encompass all aspects of what we do, andthis Bulletin provides direction for achieving thesemeasures simply and effectively through the use ofwood. It was compiled to encourage discussionamongst professionals, and provides the informationneeded to take informed action based on sustainabledevelopment principles.

The first part of the Bulletin addresses two key areas,and is aimed at:

• Providing an understanding of the principles andimportance of a sustainable approach to building;

• Recognising the multifaceted qualities of timberand associated wood products, and the role theycan play in meeting these holistic demands.

The second part illustrates theory in practice via a seriesof case studies covering a wide variety of building typesand end uses.

This Bulletin outlines the reasons why wood is an idealmaterial to use for sustainable building in the builtenvironment, including the role of timber productionand wood manufacture in the strengthening of localand regional economies.

Introduction

10 Building Green

Sustainable Development Policy — New

Zealand and Overseas

Concept

“ Sustainable development” is a concept firstpopularised by the Bruntland Commission in 1987which defined it as “Development which meets theneeds of the present without compromising the abilityof future generations to meet their own needs” (WorldCommission on Environment and Development 1987).

Sustainable development is more than just a good idea.An international policy framework offers ampleincentive and justification for planners, architects, andother urban professionals to innovate. The followingis a brief chronology of these global initiatives.

Global Initiatives

UN Conference on theHuman EnvironmentStockholm 1972

‘BrundtlandCommission’ 1987

Rio Earth Summit1992

Agenda 21 1992

FrameworkConvention on ClimateChange (FCCC) 1992

Outcome

The first world conference on the human environment addressed globalresource depletion, overpopulation, pollution, and set an agenda for furtherdiscussion. This was the UN conference on the human environment.

Defined sustainable development as “development which meets the needs ofthe present without compromising the ability of future generations to meettheir own needs” (World Commission on Environment and Development1987: 43)

The Earth Summit (or Rio Summit, as the UN’s Environment andDevelopment Conference in June 1992 is often called), focused the world’sgovernments on steps needed to implement sustainable development on theground.

Agenda 21 is part of the Rio 92 summit and, although a non-legally bindingdocument, was signed by over 170 countries, and provides a framework fora plan of action for the twenty-first century based on the principles of the RioDeclaration. It sought to ensure that:

Environmental protection becomes an integral part of the developmentprocess.

Unsustainable production and consumption methods and patterns arereduced or stopped altogether.

The “polluter pays” principle is adopted making “polluters” accountablefor their actions.

National and local strategies to demonstrate practical steps to implementsustainable development policies were to be developed. The implementationof Agenda 21 at local level is known as Local Agenda 21 (LA21), and LA21has often been the catalyst for innovation and grass roots sustainability projects(see box that follows).

The Kyoto Protocol is the first legally binding international agreement aimedat slowing, and eventually stopping, climate change. The first target is a 5%reduction in emissions in developed countries from 1990 levels over the firstcommitment period (2008–2012) . However, it is thought that a staggering

Landmarks in Sustainable Urban Development

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HABITAT 11 1996

World Summit onSustainableDevelopmentJohannesburg, 2002

60% reduction in 1990 emission rates is required to prevent dangerous man-made interference with the climate system. New Zealand’s emissions arepredominantly methane from ruminant animals (cows and sheep), carbondioxide from fossil fuel burning for the energy and transport sectors, andnitrous oxide from farms.

Habitat 11, the UN’s second conference on human settlements, sought toencourage governments to promote “locally available, appropriate, affordable,safe, efficient and environmentally sound construction methods andtechnologies in all countries…”. Habitat 11 dealt with all settlements — large,medium, and small — reaffirming the need for universal improvements inliving and working conditions. The purpose had two themes of equal globalimportance: “Adequate shelter for all” and “Sustainable human settlementdevelopment in an urbanising world”. It specifically set out actions forgovernments and the construction industry regarding planning, design,construction, maintenance, and rehabilitation; the procurement, use, andpromotion of sustainable building materials; and the production of sustainablematerials (UNCHS 1996). HABITAT 11 also stressed the importantcontribution of the construction industry to a country’s socio-economicdevelopment, and undertook to co-operate on an international level toimplement the Habitat Agenda.

Assessed global progress against existing strategies and future implementation.At this summit, “adequate shelter” was added to the list of WEHAB needs(water, energy, health, agriculture, and biodiversity)

Agenda 21 is one of the most valuable tools in the local authority toolkit. It relies heavily on localgovernment involvement and participation for implementation of over two-thirds of itsrecommendations. It addresses:

(1) Broad energy issues, for example energy used in obtaining or manufacturing building materialsand construction methods;

(2) The use of construction materials from renewable sources and from those sources that have leastenvironmental impact;

(3) The development of national strategies and regulatory measures to:

• Strengthen industries that produce local building materials, based as much as possible onlocally available natural resources;

• Adopt standards and regulatory measures to promote the increased use of energy-efficientdesigns and technologies;

• Promote sustainable use of natural resources in an economically and environmentallyappropriate way;

• Promote the free exchange of information on the environmental and health aspects ofconstruction methods and building materials;

• Introduce legislation and financial incentives to promote recycling of energy-intensivematerials and conservation of waste energy in building-materials production;

• Promote the use of financial penalties to discourage the use of construction materials andproducts that are less friendly to the environment;

• Promote research in construction industries and related activities.

Sustainable Development Policy

12 Building Green

An earlier Forest Research publication “Room for aView” (Bates et al. 2001) identified three differentscenarios in which the Australasian built environmentmight develop within the next 15 years. One of thesescenarios, The Renaissance, depicted a culture changein a society challenged by a major resource crisis.Consumers reacted strongly in favour ofenvironmentally friendly measures; Smart Growthintensification in urban areas, and sustainable naturalmaterials, such as wood, enjoyed increased marketshare. Another scenario from “Room for a View”, TheIndustrial Revolution, also had aspects of socialsustainability as its theme, with the renewal ofcommunity through regional and economicdevelopment schemes.

Further work (Shayer 2001) has underlined theplausibility of the Renaissance scenario. Demands forgreater sustainability are coming from a variety ofsources — Government, construction industrycustomers, building users, and local authorities.National sustainable development strategies across theworld are spawning more specific sustainable buildingand construction policies in the public sector as wellas in professional and industry groups. Whilst many,if not most, of them focus on energy efficiency andthermal comfort, as well as waste reduction, there isalso growing reference to materials and their impacton the environment. Indications are that the buildingindustry in various parts of the world is already feelingthe impact of these. If builders are not moved byenvironmental policies, then they are by purecommercial self-interest, to keep up with the markettrends.

Whilst voluntary guidelines and incentives haveprimarily been used to create change, there is asignificant trend towards public sector bodiesintroducing mandatory policy, particularly for workcarried out under the auspices of their organisation.Many public sector bodies state quite clearly that theirobjectives are to create momentum down the supplychain, to provide good examples, and to work with themarket to encourage change.

International

The Organisation for Economic Co-operation andDevelopment (OECD) has a sustainable developmentpolicy framework (OECD 2001) as well as a

sustainable construction section in its EnvironmentDirectorate. The International Council for Researchand Innovation in Building and Construction (CIB),regarded as the world’s foremost platform in this area,has produced an extensive report, “Agenda 21 onSustainable Construction” (CIB 1999), in response toboth Agenda 21 and Habitat 11. This recognises thatsustainable construction goes beyond technical issuesand also involves economic and social sustainability.Another, more recent organisation, the InternationalInitiative for a Sustainable Built Environment (iiSBE),is providing a world-wide permanent platform for jointaction and information exchange in the field ofsustainable building.

International and national professional organisationsfor both architects and engineers are also promotingsustainable development principles. A “Declaration ofInterdependence for a Sustainable Future”, formulatedin 1992 by the International Union of Architects (UIA1993), underpins environmental policies of majornational architectural institutes.

At a European regional level, a range of European-wide organisations and initiatives has emerged whichfurther both sustainable development and sustainableconstruction, particularly within the urban environment(e.g., Expert Group on the Urban Environment 1996).In part this has been furthered through the activities ofthe European Union and its parliament whoselegislation has generally driven the pace and directionof change in the environmental arena amongst memberStates and within the Western world (EuropeanCommission 1998, 1999, 2001).

The European Commission recognises that woodproducts have an important contribution to make tosustainable development because of wood’s particularenvironmental characteristics, from its renewability asthe main raw material, to the high level of recoveryand recyclability of most of its products (Commissionof the European Communities 1999: 15). As anexample, the French Government and key Frenchprofessional organisations have recently signed anagreement to increase the proportion of timber used inconstruction by 10–12.5% by the year 2010 (Ministèrede l’Equipement, des Transports et du Logement2001).

New Zealand

While other parts of the world have taken up theecological and social challenges and commitmentspresented by the UN’s Agenda 21 (see box on previous

Policy and Cultural

Changes

13

page), initiatives in New Zealand/Aotearoa have beenmuch slower in getting off the ground, despite thecountry’s “clean, green” image. (Knight 2000; PCE1998, 2000a,b). A change of Government in 1999 andthe impetus created by the World Summit onSustainable Development in Johannesburg inSeptember 2002 have helped the New ZealandGovernment make up for lost ground. A nationalsustainable development strategy is now taking shape,which it is hoped will address the current lack of policyintegration across central and local government.

Four key policy areas are seen as critical for sustainabledevelopment (New Zealand Cabinet Policy Committee2001):

• Human capability and employment

• Regulation of business and human activity

• Provision of physical and human infrastructureservices

• Protection and sustainable use of natural resources.

A Unique Cultural Perspective on Sustainability

One of the key themes to sustainable development isthat it must reflect cultural identity. Maori values arepart of our rich heritage and have a role to play inshaping a distinct New Zealand approach tosustainability, and sustainable building. Everything inthe Maori understanding of the world has a life force,the mauri (Harmsworth 1997). Degradation of naturaland physical resources is seen as depleting the mauriand, as a result, the wellbeing of people. The Maoribelief system introduces the concept of kaitiakitangawhich refers to the physical, spiritual, and cultural

stewardship of resources based on tikanga or socialcustoms, practices, and lores.

Traditional Maori ethics have a role to play in the waywe develop environmental sustainability, and includethese aspects in land development. Holistic and wholesystem thinking (e.g., taha hinengaro) is a fundamentalconcept that helps us understand inter-relationshipsbetween processes. The ability to learn from experience(e.g., taha whanaunga), particularly through longassociations with the environment and its resources,is critical to our future ability to deliver moresustainable lifestyles for all people.

Land, air, and water have special significance andtaonga. The treatment of these resources demands greatcare and attention (Harmsworth 1997).

Role for Timber in New Zealand Policy Changes

Timber has great potential in New Zealand for enablingAgenda 21 principles to be implemented, but theopportunity is slow in being realised. However, focuson climate change, and the need for energy efficiencymeasures on a grand scale, are expected to provide theimpetus for aspects of “sustainability” to come to thefore within the public arena and the building industry(Shayer 2001). New Zealand is well-placed to adoptand implement sustainable building principles as wehave a growing trend towards sustainable issues in thepublic sector, an abundant wood resource, andflexibility in community development due to smalltownships and a fast-changing urban environment inlarger centres.

Two national public sector organisations already havepolicies and resources on sustainable building.


New Zealand’s forests and beaches have special cultural significance toall New Zealanders

14 Building Green

Housing New Zealand (HNZC)

The Housing New Zealand Corporation has the potential to influence the building market through its extensive

construction and maintenance programme. It now has to “exhibit a sense of environmental responsibility by

having regard to the environmental implications of its operations” (Housing Corporation Amendment Act

2001).

Under this new direction, HNZC has developed an environmental strategy, with an implementation and

monitoring strategy. Whilst the major emphasis is currently with energy efficiency and its effects on health,

HNZC’s new design guidelines incorporate sustainability considerations in which wood features substantially.

A demonstration eco-house is also planned in the near future.

Building Research Association of New Zealand (BRANZ)

BRANZ has been engaged in a variety of projects relating to life cycle analysis and embodied energy

assessments, including a major Household Energy project (HEEP). BRANZ recognises the sustainable

development of our resources as a future goal and, as the building industry is a major user of resources,

careful planning and design are needed to ensure efficient and more sustainable use. BRANZ developed a

“Green Home Scheme” which offers design guidelines for new homes and a rating system based on individual

credits for a range of environmental, health, and safety issues.

The “Easy Guide to Eco-Building” describes how to carry out construction projects with consideration for

the environment, from the very early stages of design right through to the end of the building’s lifetime.

Although it does not refer directly to timber, it does refer to using “appropriate materials” by considering their

entire life cycles. Again, minimising waste on-site is a key component.

Wood is used for shutters and aesthetic detailing in this house, demonstrated in the Bo01 expo area inMalmo, Sweden.

15

New Zealand Legislation and

Policy

Legislation and policy which help to further sustainabledevelopment and building principles already exist.

The Resource Management Act (RMA) 1991

The RMA promotes the sustainable management ofnatural and physical resources. It acknowledges thatthe management or use, development, and protectionof natural and physical resources should enable peopleand communities to provide for their social, economic,and cultural wellbeing (RMA Section 5 (1)(2)). Thisdefinition echoes the principles established byBrundtland in 1987.

The relevance and value of the RMA to urbansustainability is the subject of continuing debate anddiscussion. It has been accused of failing to deliverquality in design and a strategic context, focusingalmost exclusively on the minimisation of impacts. TheRMA, while not a planning Act, does offer sufficientscope to justify the consideration of sustainability inbuilt development.

The New Zealand Building Code (NZBC)

New Zealand’s building regulatory system is neutralon sustainable building. The performance-based NZBChas no specific reference to sustainability or life-cycleanalysis, although the incorporation of these aspectswould be helpful to stakeholders.


The NZBC comprises regulations made under theBuilding Act. It is a hierarchy of three performancestatements — Objective, Functional Requirement, andPerformance Requirement — supported by ApprovedDocuments comprising Definitions, VerificationMethods, and Acceptable Solutions. Many of theseapproved documents call up Standards relating tobuilding materials and systems.

The most important of these Standards for woodenbuilding is NZS 3604 Timber Frame Buildings, anAcceptable Solution under the NZBC. It prescribeswell-illustrated structural and cladding requirementsfor timber frame construction at a level of detailsuitable for both designers and builders. This codeembodies the best of traditional practice with fullyengineered span tables for all components andfasteners. It refers to many other Standards coveringtimber properties, grading, preservation, etc. AnotherStandard covers energy efficiency provisions for smallbuildings. Other codes provide for the engineeringdesign of heavy timber construction such as glue-laminated portal frame buildings.

Taken together, these building codes and Standardsexert a powerful influence on the efficiency, durability,safety, and popularity of timber construction.

However, the incorporation of life-cycle analysis wouldalso be helpful. The Building Industry Authority couldbe lobbied to change the approved documents used bylocal authorities to ensure that consideration is givento the sustainable characteristics of timber andadherence to the building code and RMA. Suchlobbying was done successfully by earth buildinglobbyists.

Rising sea levels due to climatic change may have an impact upon many coastalNew Zealand built environments

16 Building Green

Local Government Bill 2002

The Local Government Bill increases the ability oflocal government to act on a range of sustainabilityrelated issues. The Bill gives local authorities a newpurpose:

“ to enable local decision making, by, and on behalfof, individuals and their communities, todemocratically promote and action their social,economic, environmental and cultural wellbeingin the present and in the future”.

The Bill also gives local authorities a positive role inthe delivery of sustainable development. Long TermCouncil Community Plans (LTCCP) are required bythe Bill and will supplement the RMA as a mechanismfor the delivery of social and economic benefits. Thestrategic and participatory approach required toproduce a LTCCP may mean that integrated solutionsto complex issues, such as energy efficiency,biodiversity, waste management, and climate change,may be more achievable (Hutchings & Hogg 2002).

Climate Change Foundation Policies

Domestic policy measures to reduce emissions (suchas a carbon charge on fossil fuels) will come into effectfrom 2008. However, there are already somefoundation policies that offer benefits such as improvedcomfort levels in homes and cost savings fromimproved insulation. Particularly relevant to the BuiltEnvironment are the National Energy Efficiency andConservation strategy, the New Zealand WasteStrategy, and the Government’s preferred policypackage for the climate change policy itself. Earlyspecifications of the impact of these policies on BuiltEnvironment policy and practice indicate:

• New buildings should maintain an environmentof between 18° and 25°C without significantadditional energy utilisation, and pre-1977 homesare to be retrofitted for energy efficiency by 2016(NEECS 2001);

• Mean energy performance targets for commercialbuildings will be higher by 2016 (NEECS 2001);

• By 2008, 50% less construction and demolitionwaste will be going to landfills than at 2005(NZWS 2002);

• Territorial Authorities are to ensure appropriatespace allocation for recycling facilities in multi-residential and commercial facilities by December2005 (NZWS 2002);

• There will be increased use of renewable energy,including solar hot water heaters and wood-to-energy schemes (NCCCP 2002);

• There will be an average rise in household energycosts of between $104 and $260 per year from2008 (NCCP 2002).

The emission-cutting incentives introduced now,whether fiscal or legislative, are only the tip of theiceberg as we enter a global, carbon-constrained,economy.

Putting Policy into Practice

in New Zealand — Some

Territorial Authority

Initiatives

Some significant and exciting initiatives within NewZealand are already under way. Local authorities facean exciting future with new opportunities to take a leadin the delivery of sustainable development solutions.

Waitakere City Council

Waitakere City Council is regarded as being at theforefront of local authority activity in New Zealand topromote sustainable approaches to the builtenvironment. Advice for those involved in buildinghouses as well as mandatory regulations for Councilbuildings are key examples.

Sustainable Home Guidelines

This guide (Waitakere City Council undated) isprimarily for use with residential houses. It providespractical information about energy, water, materials,safety, waste, and other eco-building issues for buildingan eco-home or to make an existing home a little moresustainable. It includes a section on life-cycle analysis,complete with an assessment of eco-building materials.However, relying on common sense is advised as beingmore effective than complicated analysis. The use oftimber is encouraged for its renewability, embodiedenergy, and life-cycle impact, as long as it is fromcertified sustainably managed sources. Timber isacknowledged as the most culturally appropriatematerial for New Zealand. It recommends timber fromsustainable plantations of a range of eucalypts,blackwood, and cypresses.

17Sustainable Development Policy

The Better Building Code

This code (Waitakere City Council 2000), for use in-house and for suppliers and contractors, providesstandard eco-clauses for tendering, and briefingdocuments for the design and construction of publicbuildings. It is equally applicable to many privatecommercial buildings. It has recently been adopted asa minimum standard for all Waitakere City Councilbuildings. All timber used has to be from a New

Zealand plantation or from independently certifiedsustainable sources. All materials need to have theiroverall life-cycle costs (environmental and financial)considered. Timber is encouraged generally as a goodchoice when evaluated against another material.

The Code provides a brief explanation behind theclauses, along with additional information that canbe included in the briefs to assist designers.

And,

The least environmentally damaging material should be chosen for each application. Consideration

should be given to embodied energy, toxicity, damage caused throughout the material’s lifecycle,

sustainability, and renewability of the resource, and to the technical performance of the material.

The following describes preferences for some materials over others and lists materials that are not to be

used:

New Zealand-grown plantation timber should be used wherever possible, and in preference to plastics and

steel where timber use is appropriate. Timber framing, for example, is preferable to steel framing, because

of the energy consumed in steel manufacture. Glue-laminated timber beams can often replace steel beams.

However, timber alone cannot meet every need, and complementary materials, sourced sensitively, should

be used to enhance the overall design.

Only New Zealand plantation-grown timber or timber from certified sustainable sources (Forest Stewardship

Council) should be used. This means no rimu, cedar, teak, or kwila or other rainforest timbers. However, the

use of recycled and wind-fell timbers is encouraged.

Locally made materials are preferable because they consume less energy during transport. This also supports

the local economy.

Products and systems which are repairable and serviced locally are preferable.

Extracts from ‘The Better Building Code’

All timber, including any composite wood products, is from New Zealand plantation grown timber

or from an independently certified sustainable source.

Reason:

This will ensure that we do not contribute to the destruction of old growth forests in New Zealand or abroad.

Certification becomes important because claims by timber merchants about the sustainability of overseas

timber are very difficult to assess.

Possible Solution:

At present the only accepted available type of certification is the Forest Stewardship Council certification.

This would need to be obtained in writing and verbal claims by timber merchants are not to be relied on.

In practice this will mean no cedar (though certified sources are likely to become available in the next

couple of years), rimu, kwila, or other tropical timbers. Instead New Zealand-grown pine, Eucalyptus, or

macrocarpa could be used. Hardened pine presents a good alternative to tropical hardwoods (this is a

commercial process which hardens pine by pressure impregnation with a hardening chemical).

Cost Implications:

New Zealand-grown pine is widely available and price competitive. Some of the less common New Zealand-

grown plantation timbers can be slightly more expensive; however, because the price for timbers from non-

sustainable sources does not reflect their true cost, sustainable timbers still offer the best value for money

for Council [building projects].

18 Building Green

Learning from Others —

Some Overseas Local

Authority Initiatives

Many local authorities around the world have facedsimilar challenges in promoting and implementingsustainable development. There is now a growingbreadth of experience which is shared through nationaland international networks (see Appendices).

South Somerset District Council

and Somerset County Council, UK

Somerset County as a whole has been working for someyears on developing and integrating comprehensivelocal Agenda 21 strategies and policies into its workat a corporate level, and together with South SomersetDistrict Council they have some of the most radicalsustainable building policies in the public sector.Mandatory consideration of sustainable buildingprinciples in new Council buildings, as well assustainable consideration in procurement, operation,and management of Council buildings, has recentlybeen required. Whole-life costing and life-cycleassessment have to be undertaken in each new buildingcosting in excess of £100,000 (as experience grows).Those costing over £300,000 need to reach BREEAM’s“very good” standard. Timber framing is recommendedspecifically rather than masonry or steel construction.

Support for sustainable construction is part of SouthSomerset District Council’s corporate aims, withtargets on energy and the proportion of projects whichare exemplars of sustainable construction. Forexample, one of the targets is to achieve sustainableconstruction and combined heat and power in keydevelopment sites by 2011.

The planning system has been used to directdevelopment towards greater incorporation ofsustainable construction, through directions in thedistrict plan and through planning guidance. Guideshave been produced for a wide range of buildings —residential, community, and commercial buildings, andschools. Small grants are available to those buildingsincorporating any of a range of 10 differentsustainability features. The Council works withhousing associations to encourage them to adopt thesepractices. Timber is regarded as a preferred materialas long as it comes from sustainable sources from eitherthe United Kingdom or Northern Europe. It particularlyencourages the use of locally produced timber andtimber products, as well as local materials and labourgenerally.

This work has been backed up by a conference,seminars, and exhibitions and by the Somerset Trustfor Sustainable Development, recently launchedthrough the support of the County and District Councilsand the private sector. Its aims are to further sustainablebuildings county-wide, including all the other districts,by “making sustainable design and building practicesnormal rather than exceptional throughout Somersetby the year 2010.” This, the Trust says, is policy thatGovernment guidance indicates should followautomatically from Agenda 21 and Best Valuecommitments. In particular, it considers that thesuccessful implementation of these policies is criticallydependent on “officers’ attitudes, standard workingprocedures, ‘up-to-dateness’ in thinking and corporatepriorities.”

City of Portland, Oregon, USA

Portland’s Office of Sustainable Developmentlaunched its new green buildings policy early in 2001(City of Portland 2001) after almost 2 years of input

Paints, finishes, and glues should be water-based wherever possible. However, care should be taken to

choose products that will be durable and suitable for the intended use and that are able to be maintained

easily. Use of “Environmental Choice” accredited paints is encouraged.

Soft PVC (vinyl) should be avoided where possible. Linoleum can be a good alternative for floor coverings.

Pre-cut and pre-nailed framing reduces the amount of off-cuts generated, because of better efficiencies at

the pre-nailing yard than on site.

The use of materials with recycled content, such as concrete containing crushed concrete as aggregate, is

encouraged, as is the re-use of materials. The Auckland Regional Council is in the process of publishing a

directory of recycled building materials.

19

and review by the City and building industry leaders.This comprehensive set of green building policies isdirected towards the City as well as the private sector:

• Green building practices are now mandatory forall facilities and projects constructed, owned,managed, or financed by the City;

• The Portland Development Commission (PDC),which is regenerating part of Portland, has to adoptPortland’s LEED Green Building Rating Systemand City of Portland Green Building Policy goals,and incorporate green building practices into eachof its ongoing and future programmes.

For the private sector this is voluntary, but financialincentives are provided for residential and commercialbuildings which use the LEED system. The G/RatedCommercial Incentive encourages design andconstruction of environmentally responsible


commercial, institutional, and multi-storey housingdevelopments. Recognising that green innovationsrequire initial investment in research and design, theprogramme’s financial incentives help support the costsof professional services during early planning anddesign development. The commercial programmeoffers financial incentives of up to $20,000 for projectsthat meet Portland’s own LEED criteria, acustomisation of USGBC’s LEED national greenbuilding rating system to accommodate local codes andenvironmental conditions.

To support the development of their recent greenbuilding strategies, an inter-departmental group withinthe city is working on developing a 20- to 30-year life-cycle analysis tool for estimating the design,construction, and operations and maintenance budgetsfor all City Capital Improvement Projects (CIP).

20 Building Green

Wood Construction and

Climate Change

There is now strong evidence that most of the globalwarming observed over the last 50 years is attributableto human activities, namely the emission of greenhousegases (GHG) and in particular carbon dioxide (CO2)(NZCCP 2001). Sustainable forestry plays a major rolein the carbon cycle as trees absorb and lock up carbondioxide during growth. In this section we examine theimpact of climate change on the built environment,the carbon neutrality of wood, and how using woodrather than alternative materials in buildings cansignificantly reduce emissions to the atmosphere.

Effect of Climate Change on the

Built Environment

Global warming is causing world-wide climate change,with rising sea levels and a greater incidence of storms,droughts, and floods threatening low-lying populations,ecosystems, and agricultural practices. This isparticularly relevant to New Zealand as a country thatrelies predominantly on primary resources and tourismfor its economy, has vast lengths of coastline, and hasunique flora and fauna.

The effects of climate change on society and our naturalenvironment are divided into three categories: impacts,adaptation, and mitigation.

Impacts include increased risk of summertimeoverheating, increased flooding (90% of thepopulation live within 45 km of the coast),erosion, and damage from cyclones. Inaddition the socio-economic impacts includeeconomic and legislative measures introducedby regional and national governments, andincreased insurance premiums.

Adaptation measures include activities thatreduce the impact of climate change. Forvulnerable buildings this includes usingflood-resistant material and raising thebuilding further above the ground, providingadequate shade for windows, and increasingventilation, such as passive venting.

Mitigation measures are steps to alleviate andcombat climate change. From the perspectiveof the building industry there are several areaswhere gains can be made.

Changing Climates — Changing

Homes

New Zealand households use 35% of the nation’selectricity, 50% of its LPG, nearly all its fuelwood,and 15% of its natural gas. The building industrycontributes 6.6% of New Zealand’s CO2 emissionsduring construction. However, the largest source ofgreenhouse gas emissions from buildings is from theoperating energy use, which could increase further ifair conditioning units become standard (BRANZ

Wood in the Sustainably Built

Environment

The popularity of MtMaunganui and Papamoa hasbrought recent extensivedevelopment.

Climate change may see therise in popularity of othercoastal areas of New Zealand,and an increase in energy-intensive air-conditioningrequirements

21

2001). The Energy Efficiency andConservation Authority (EECA)estimates that generating energy forall the appliances in the averagehome produces about 5 tonnes ofclimate-changing carbon dioxide ayear — as much as two small cars(EECA 2002). Building green, usingrenewable resources for both energyand materials, reduces the carbonfootprint of buildings (emissionsreleased during lifetime from conceptto disposal). Emission reductions canoccur at all stages throughout thebuilding’s lifetime through the choiceof raw material, construction process,service requirements (heating andlighting), demolition, and disposal.

Reducing Carbon Emissions by

Using Wood

Carbon Neutrality of Wood

Trees remove carbon dioxide from the atmosphere viaphotosynthesis, retaining carbon in biomass. Anexpanding forest is a carbon sink (carbon sinks areany natural or man-made systems that absorb and retaingreenhouse gases, mainly carbon dioxide). Carbonabsorption continues until a forest reaches a steady state(maturity) when the carbon remains locked in. Thus

the forest acts as a carbon reservoir, even if individualstands are continually harvested and replanted. Woodproducts from sustainable yield forests, wherereplanting occurs after harvesting, are also carbonstocks as about half the dry weight of wood is carbon.At the end of the product’s lifetime, carbon is releasedback into the atmosphere as carbon dioxide or methanewhen disposed of by combustion, or landfilldecomposition, respectively. Once carbon is releasedback into the atmosphere, the cycle continues with treesabsorbing carbon. Wood products release carbon thatwas absorbed during growth and are therefore carbonneutral.

Wood in the Sustainably Built Environment

Wood is an integral part of the carbon cycle, allowing carbonto be recycled.

Generating energy for home appliances produces 5 tonnes of carbon dioxideper year.

22 Building Green

Timber structures are also easier to move, dismantle,reuse, and recycle than other structures. When awooden building is dismantled, the resulting woodproducts can be reused and recycled or easily disposedof as wood is biodegradable and can be burnt (ifuntreated) to produce clean, green, renewable energythat not only substitutes for fossil fuel but also reducesthe volume sent to landfill. For these reasons a 17%increase in wood usage in the building industry couldresult in a 1.5% reduction of total energy consumed inNew Zealand. This represents a 20% reduction incarbon emissions from the manufacture of all buildingmaterials (Buchanan 1999). The timber resource forsuch an increase is domestically available and wouldhave added benefits related to national and regionaleconomic development and job security.

Current and Traditional

Trends of Wood Use in the

Building Sector

The use of wood as a building material has a longtradition in many parts of the world. Since 1976, annualconsumption of softwood timber in North America hasshown an average increase of 1.4% (Cohen 1996).Softwood timber production in the United Kingdomis projected to increase by 67% by 2020, with theprimary market for the expanding resource beingstructural timber for construction (USDA 1999).Timber frame construction is the predominant form ofhousing construction used in more than 90% of housingstarts in Australasia, North America, and Scandinavia.

Energy Efficiency of Wood

Wood, rather than alternative construction materials,is the first choice for those looking for a sustainableapproach to construction. Manufacturing woodencomponents requires less energy than many othercompeting materials, such as aluminium or steel. Inaddition, 50% of the energy used in wood processingis obtained from wood residues. This bioenergy(burning wood for energy) is carbon neutral, in contrastto fossil fuel combustion which is a one-way releaseof emissions.

How much wood do we use?

Of the 20 million m3 of roundwood harvested in New Zealand per year, 12 million m3 is processed into

timber products for domestic or export markets, and another 6 million m3 is exported in log form. New

Zealanders are among the world’s biggest consumers per capita of sawn timber, reconstituted wood panels,

and wood products, with a total domestic

consumption of 3.1 million m3 sawn timber per year

or approximately 2 m3 roundwood equivalent per

capita per annum (MAF 2000).

The construction industry is the primary user of

domestic solid wood products servicing around

21 000 new house starts annually with a value of

NZ$2–3 billion. There are 1.4 million homes

(Statistics NZ 2001) in the current building stock that,

combined with non-residential buildings, contain 36.9

million m3 of wood products.

Wood can be used in a large variety of applicationsaround the home, as well as for construction

23

Timber is culturally favoured in New Zealand becauseof significant softwood resources, a tradition of timberconstruction, building expertise, and building codesand standards for timber-frame construction. As aresult, timber-framed houses are relatively cheap andquick to construct and are simple to modify. A sizeableculture and industry has been developed around timberframe construction.

In Australasia, both the native settlers and later colonialpioneers used the timber that was abundantly availableto them for both shelter and fuel. The traditional low-density suburban timber frame and weatherboard househas been replaced recently by other materials.Australasian producers of solidwood products arefacing increasing competition from non-woodsubstitutes with the emergence of new buildingmaterials such as light-gauge steel profile framing, self-levelling random reinforced lightweight concrete,plastic claddings, linings, underlays, mouldings,joinery, and fittings, as well as plastic lumber andconcrete masonry materials, where traditionally timberlandscaping materials have been used. Nevertheless,wood is still one of the most highly used constructionmaterials in New Zealand, particularly for theresidential market, where market share for timber-framed buildings is greater than 90%.

For the New Zealand market, framing timber has, inthe last 6 years, moved from green boric-treated timberto dry untreated framing. In conjunction with thischange there has been an increase in the use ofmechanically graded framing compared to visualgrading.

Another influence is customer preference. A goodexample is the large amount of western red cedarimported from Canada (about half the total volume oftimber imported). This is a naturally durable timberwhich is used for weatherboards. Although radiata pinecan be and is used for cladding, it requires preservativetreatment and some people prefer to use untreatedproducts. It should be borne in mind, however, thatwestern red cedar may be cut from unsustainablymanaged forests, and so sources should be checkedbefore this timber is specified. Also, its durability stemsfrom naturally occurring toxic chemicals in theheartwood which have been associated with lungdisease, and so care should be taken when machiningthis timber.

Sustainable Building —

Some Definitions

Our understanding of sustainable buildings iscontinually developing. The more we learn, the morewe are able to design buildings that make fewerdemands on the earth’s resources and improve ourquality of life. The following section draws onsuggestions from various sources as to what constitutessustainable building.

Ministry for the Environment (MfE)

MfE uses a definition for sustainable management ofthe environment which includes aspects of health, andcultural and social wellbeing. Some of these aspectsare applicable to construction.

“Sustainable management means managing theuse, development, and protection of natural andphysical resources in a way, or at a rate, whichenables people and communities to provide fortheir social, economical, and cultural wellbeingand for their health and safety while:

• Sustaining the potential of natural andphysical resources (excluding minerals) tomeet reasonably foreseeable needs of futuregenerations; and

• Safeguarding the life-supporting capacity ofair, water, soil, and eco-systems; and

• Avoiding, remedying or mitigating anyadverse effects of activities on theenvironment”.

Framing timber is our most popular residentialconstruction material.


24 Building Green

Building Research Association of

New Zealand (BRANZ)

BRANZ (BRANZ et al. 2000) outlines four sustainablebuilding principles.

Sustainable building:

• Connects to and works with its localecosystem;

• Does not create problems for someone else,and minimises negative impacts;

• Adopts technologies appropriate to localconditions;

• Expresses the culture and ecology of thepeople.

Ecospecifier

Australia’s EcoSpecifier project at the RoyalMelbourne Institute of Technology’s Centre for Design(RMITCD 2000) identified that environmentalsustainability includes:

• Avoiding or reducing dependence on non-renewable resources

• Increasing resource use efficiency

• Minimising impacts on bio-diversity

• Recovering, reusing, and recycling materials

• Encouraging the use of more-durablematerials requiring low ongoing maintenance.

City of Seattle

The city of Seattle in the United States defines sustainable building as:

“(the integration) of materials and methods that promote environmental quality, economic vitality, and social

benefit through the design, construction and operation of the built environment. Sustainable building merges

sound, environmentally responsible practices into one discipline that looks at the environmental, economic

and social effects of a building or built project as a whole. Sustainable design encompasses the following

broad topics: efficient management of energy and water resources, management of material resources

and waste, protection of environmental quality, protection of health and indoor environmental quality,

reinforcement of natural systems, and integrating the design approach”

(City of Seattle 2000).

Existing trees on a site can be used for shelter and privacy,

25

Holistic Approach to

Sustainability

Although sustainability applies to the physical buildingelements of a project, the term also considers thebuilding’s impact on human health, and the immediateenvironment and landscape. The emphasis of thebuilding and mix of materials and design willultimately be dependent on the overall purpose of thebuilding, its clients, location, money available, andpersonal preferences. In this way, sustainableconstruction incorporates much more than onlyembodied energy of materials, and must be addressedholistically throughout the life of the construction.

Low Impact

A building which is designed using sustainableprinciples will enhance, but have very little impact on,

the environment. Fisher (1992) described the fiveprinciples of environmental architecture as making sureall measures are taken to:

• Ensure that materials and building systemsdo not emit toxic substances and gases intothe interior atmosphere;

• Ensure that the building’s use of energy isminimal;

• Use building materials and products thatminimise destruction of the globalenvironment;

• Relate the form and plan of the design to thesite, the region, and the climate, and relatethe form of building to a harmoniousrelationship between the inhabitants andnature;

• Achieve an efficient, long-lasting, and elegantrelationship of use, areas, circulation, buildingform, mechanical systems, and constructiontechnology.

What are the Principles of Sustainable Construction?

Sustainable construction is new building and refurbishment that promotes environmental,

social, and economic gains now and for the future.

It follows these basic principles:

01 Siting

Buildings should “sit” appropriately in their surroundings — be sensitive in scale

and style to the character of the existing natural and built environment, re-use

previously developed sites wherever possible, and develop locations already served

by transport, communications, and utilities infrastructure.

02 Materials

Construction should prioritise the use of local and natural/recycled materials.

03 Construction Techniques

The latest environmental techniques should be specified — to save energy, water,

and waste during a development’s construction, operation, and decommissioning

phases.

04 Information Technology and Communication (ITC)

Construction design and specification should maximise future ITC capacity.

05 Community Involvement

Communities should be informed about, and involved in, the planning and design

of buildings in their area which should be safe, secure, and accessible to all.

06 Local Sourcing

The use of local labour, training, design, and creativity should be maximized to

support local economies and minimise energy use in transportation/travel.

From: Future Foundations: Building a Better South West produced by Sustainability

South West, a partnership of central and local government agencies and regional private

and public sectors covering Bristol and the south-west of England.


26 Building Green

Pleasant Atmosphere

People have many different requirements andexpectations from buildings other than simply shelter.We appreciate colour, form, light, space, shape, andaesthetics. There are more subtle considerations suchas aroma, touch, and warmth which combine to givethe user a certain atmosphere or experience about abuilding. The atmosphere experienced will draw asense or emotional response from the dweller. Indeed,many real estate agents tell of clients who “fell for” ahouse, or who sensed there was “something right (orwrong)” about the house they inspected. In apsychometric study of wood and non-wood moderncorporate interiors (Ridoutt et al. 2001b), organisationswhose corporate interiors had no wood decoration wereleast preferred as places of potential employment. Asimilar study (Ridoutt et al. 2001a), looking atperceived first-impressions of office workers based ontheir office environment, found a more favourable first-impression for workers whose offices contained a highdegree of wood in the interior décor.

Building with Wood —

Engineering Aspects and

Life-cycle Analysis

Engineered buildings use rational engineeringprinciples to supplement the knowledge that isincorporated into the design and construction oftraditional buildings. The inclusion of theseengineering principles reduces costs while improvingperformance and reliability. Engineering principles forwooden construction are incorporated into codes andstandards such as the Timber Frame Buildingsstandard, NZS 3604:1999.

Building codes, enforced by an act of parliament,require all buildings of a particular type, regardless ofthe materials from which they are built, to meet similarstructural performance levels in terms of safety(strength) and serviceability (deflections and vibrationin use).

Areas that are amenable to engineering principles arestructure, fire, thermal performance, acousticperformance, and aspects of durability. Keysustainability principles such as efficiency in use ofmaterials and energy and minimal impacts on theenvironment are part of an engineering approach.

“It is essential to experience all the times and moods of one good place”.

Thomas Merton

This means that it will keep occupants healthy bycleaning and revitalizing interior air with filtration andplantings; it will be designed so that the constructionelements have produced minimal waste and usedminimal energy; it will blend in rather than stand outin a locational setting, and so the materials and designmust suit either the natural surroundings, or the existingurban landscape; on-site assembly will be in a shorttimeframe so as not to disturb and disrupt neighboursand will cause minimal change and disruption to theexisting infrastructure and landscape (including treeremoval, soil displacement, and new infrastructurerequirements).

Passive Design

The Australian bulletin “ Environmentally FriendlyHousing Using Timber” states that the use of designcan contribute to minimising non-renewable energyconsumption (NTDC 2001). Keeping the environmentcomfortable through passive design techniques canhelp energy efficiency by reducing the need to changethe environment through air-conditioning or additionalspace heating.

Building around existing site features can provide endresults of greater interest!

27

Timber has many advantages when used alone, or inappropriate combination with other materials. Thissection outlines the various performance properties oftimber and highlights the advantages in using woodfor sustainable construction.

Structural Performance

Structural safety, or resistance to failure under loadsimposed by occupants and natural forces, such asstrong winds or earthquakes, are designed intobuildings. A probabilistic approach takes account ofthe loads the building may be required to withstandduring its design lifetime, the strength of the materialsused, and the level of safety demanded by society interms of an acceptable risk of failure.

Strength and Stiffness

Compared with other materials, solid timber beamshave relatively high strength for their stiffness, thusthe size of many wood members is determined by theneed to limit deflections and annoying vibrations,rather than to prevent failure. In the Table below, typicalstructural material properties are compared. Thus awood building, with an extra reserve of strengthbecause stiffness criteria have to be met first, may have

Allowable strength properties of common structural materials

–––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

Wood Steel Concrete

Radiata pine Structural Unreinforced

No.1 Framing steel In compression

–––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

Characteristic bending strength (MoR) (MPa) 17.8 210 17.5

Bending stiffness (Modulus of Elasticity) (GPa) 8 210 25

Ratio of strength to stiffness 2.2 1.0 0.7

Density (kg/m3) 500 7830 2490

Specific strength – MoR/Density (kPa.m3/kg) 36 27 7

Specific stiffness – MoE/Density (MPa.m3/kg) 16 27 10

–––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

Wind and Earthquake Resistance

Wood structures, being lightweight and often havinglightweight claddings, must resist uplift and horizontalloads from wind by having well designed andassembled joints. In most wood structures the claddingand lining materials reinforce members, as well asjoints. Properly fastened sheet materials also act asbracing to keep the building square under horizontalloads. Wind loads are brief loads and, althoughlightweight structures respond rapidly to brief loads,wood has a higher strength under brief loads than longduration loads. Earthquake-resistant structures should

a lower probability of failure than say a steel or concretebuilding. This is not because it has been designed forhigher strength, but is simply a consequence ofsatisfying stiffness requirements. When woodenbuildings fail under severe loads, it is often the jointsthat fail because joints are more often designed forstrength than stiffness.

Joint detailing is important due to the high number ofmembers used in timber frame designs.

Testing structural timber performance.


28 Building Green

be lightweight (so that the forces generated by groundaccelerations are low), and ductile (so that largedeformations can occur without high loads andconsequent failure). Timber frame construction has aparticularly good reputation for earthquake resistancedue to a favourable combination of light structureweight and ductile jointing systems. Wood membersoften fail in a brittle manner, but wooden joints, usingmetal fasteners such as nails, can be designed to yieldin a ductile fashion and limit the loads on the woodenmembers to below their failure loads. As for wind loads,well-fastened sheet materials effectively brace thebuilding and keep it square under horizontal earthquakeloads.

Load-sharing

The relatively light weight of wood buildings placesless demand on foundation systems and enablesbuildings to be built with less ground disturbance. Polefoundations allow construction on sites which wouldbe uneconomic for heavy construction. In addition tobeing light weight and ductile, timber frameconstruction is a system where loads are carried alongmultiple paths by members, crossing members, andcladdings all tied together into a load-sharing structure.Such structures are inherently safe and resistant tocollapse in the event of failure of a single member asthe loads are picked up by its neighbours. Thisstructural redundancy, or load-sharing behaviour, is ofvalue in resisting both brief impact loads and longerduration loads.

Fire Resistance

In lightweight structures, the metal and wood membersare protected by fire-resistant linings such as plasterboard. These tested systems allow occupants time toescape. Building design and surface protectionimprovement measures are now being favoured overthe use of fire retardant.

The risk of loss of life in a wooden building is nogreater, and may be less, than the risk in a non-woodbuilding. Heavy timber construction has a well-provenresistance to intense fires. Wood loses strength slowlyat high temperatures and chars at a slow and predictablerate of about 0.6 mm/min, and so a fire resistance ofhalf an hour is achieved with 18 mm of wood beingcharred. The charred material protects the material on

the inside, and in many cases the wooden structureretains sufficient strength to be rebuilt upon. Thisis in contrast to metal beams which have beenknown to melt and lose all strength in conditionswhere heavy wooden beams have lost only a smallproportion of their original strength.

Primary protection against fire involves reductionor elimination of ignition sources, prevention offire spread by use of fire-resistant surface finishesand sprinkler systems (economical domesticsprinkler systems are now available), and greaterattention to reducing the fire hazards of furnishingsand contents. In these respects, wooden buildingsare neither better nor worse than buildings of othermaterials.

Poles can be used with little ground disturbance, andrequire minimal processing energy.

Load-sharing in timber frame designs increases safety.

29

Thermal and Acoustic

Performance

Thermal Design

Engineering principles, including layout andorientation of rooms, windows, and overhangs, andthe thermal properties of the materials used for thestructure, claddings, windows, and insulation, can beused to ensure that buildings are warm in winter andcool in summer.

Thermal insulation is probably the most importantsingle factor in good thermal performance of buildings.High insulation levels enhance the effectiveness ofthermal mass as they reduce heat flows in and out ofthe building thus reducing the need for heat storage.Generally timber frame construction is the easiest formof construction to obtain high insulation values because

wood is a poor thermal conductor and timber frameconstruction readily accommodates insulationmaterials. Metal framing systems suffer from thermalbridging of insulated cavities and require thermalbreaks to reduce heat conduction through the frame.Relative thermal performance for different buildingmaterials is shown in the Table below.

Thermal mass can be used to stabilise internaltemperatures, reducing high temperatures during theday and increasing low temperatures at night. However,the National Timber Development Council (2001)found constant and uniform internal temperatures arenot necessarily the most desirable state. Differentrooms at different times and seasons have differenttemperature requirements. Cool bedrooms at night inthe summer, a warm kitchen in the morning in winter,a warm office where sedentary activities take place,and a cool gym are examples.

Thermal properties of building materials

–––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

Material Radiata Radiata Particle- Hard- Gypsum Cork Concrete Brick- Steel Alumi- Earth Water

property pine pine board board board board work nium

plywood

–––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

Density (kg/m3) 500 530 640 1025 880 128 2340 1700 7800 2700 1280 1000

Thickness, t (mm) 90 7.5 19 4.5 10 12 100 115 1.2 1.2 500 100

Conductivity, k (W/m.K) 0.1 0.14 0.12 0.22 0.17 0.039 0.94 0.96 50 210 0.71 0.6

Thermal resistance, R, for

given thickness (m2.K/W) 0.90 0.05 0.16 0.02 0.06 0.31 0.11 0.12 0.00 0.00 0.70 0.17

Heat capacity, mass

based (J/kg.K) 2090 2090 1500 1680 1050 1800 800 840 880 1170 4190

Heat capacity, volume

based (MJ/m3.K) 1.0 1.1 1.0 1.7 0.9 0.2 1.9 1.4 0.0 2.4 1.5 4.2

––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

As can be seen from the Table above, woodhas a significant thermal capacity as it is agood insulator, and so getting heat in andout of the timber is more difficult than withsome materials. In timber structures,thermal capacity may be deliberatelyincreased where it is most effective, byincorporating other materials, andminimised where it is least desirable.Examples are use of a concrete blockinternal wall or tile-clad concrete floor closeto a heat source such as north-facingwindows or a solid fuel stove. Thermalmass is a two-edged sword and should beminimised where it is a problem such as inoccasionally heated or used rooms on thesouth side of a building. In the end, allinternal climates are compromises and most

requirements can be met economically and withinacceptable limits with the flexibility of design,construction and operation offered by timber buildings.


A clay-brick wall is used to good effect in this timber classroom as asound and thermal barrier.

30 Building Green

Acoustic Design

Sound and vibration isolation of living spaces fromoutside and, in multi-residential buildings, fromneighbours is important for the comfort and ongoingsatisfaction of the building occupants. Very effectiveacoustic isolation is readily attainable in timber-framedbuildings by taking advantage of the double-leaf natureof timber-framed walls and floors. The addition of morelayers of airtight linings and the use of a sound-absorbing infill improves acoustic isolation.

Further improvements are made by minimising thephysical connections inside wall and floor cavities; thismay be in the form of double stud and plate wallconstruction, floating floors, or ceiling linings attachedto frames which are not attached directly to the above-floor joists.

Why Wood?

New Zealand produces wood more efficiently and with less impact on the natural environment than almost

anywhere else in the world. Forests have important roles to play in delivering sustainability, because they:

• Soak up carbon dioxide, one cause of climate change

• Create habitats for many native birds and animals

• Create jobs and wealth across the regions

• Have the potential to offer recreation and tourism opportunities

• Provide timber and other wood products sourced from a renewable resource.

Timber as a building material has many natural benefits due to its:

• Strength

• Light weight

• Simple construction systems

• Durability

• Aesthetic quality

• Warmth

• Biodegradability

• Renewability

• Low embodied energy

• Versatility and ease of working

• Diversity of end use

• Recyclability.

There is a growing realisation that we cannot keep on consuming resources at current levels. Buildings

consume up to 40% of all energy and material resources, release 30-40% of CO2 emissions, and contribute

up to 40% of all man-made wastes (ASMI 1999).

Global habitat loss and climate change are symptoms of resource-hungry lifestyles and economies.

Indications are that the building industry in various parts of the world is already feeling the impact of global,

national, and local sustainable development policies arising from the UN’s Rio Earth Summit in 1992, and

will continue to be transformed by the growing extent and sophistication of explicit building policies in both

the public and private sectors.

Shayer (2001) indicated that most organisations working in materials research cite timber as generally

having the properties and qualities which best match the growing sustainability criteria, and that sustainably

managed wood and wood products therefore have the potential to be recognised as key components of the

sustainable urban fabric.

As is true of any lightweight construction, includinglow-density concrete, the low mass of timber-framedbuildings can result in increased low-frequency soundtransmission. This, however, can be improved by usingheavier linings, increased wall and floor cavity depths,and structural disconnections. On the other hand, thenatural resilience and vibration damping abilities oftimber and timber products result in reduced mid- tohigh-frequency acoustic transmission as compared toconcrete and structural steel.

Good acoustic isolation need not be expensive whenincorporated at the design stage; the difference in costbetween good and poor acoustic design is only a fewpercent of the overall building cost. Additionally, as abonus, good acoustic isolation design often naturallyresults in other benefits, such as improved thermal andfire resistance.

31

Aesthetic Considerations

There are also other considerations to take into accountin assessing the appropriateness of wood products(Willis & Tonkin 1998). While there are obvious meritsin using wood products for building, the use of woodalso needs to be balanced with contextualconsiderations — overall aesthetics, landscape, and theculture, for instance, as well as preference, costs,functionality, and pragmatism.

Value and Image

Different countries have their own cultural approachto the use of timber, usually relating to their climateand the extent of their own production forests. NewZealand, Australia, Scandinavia, and the United Stateshave a tradition of using timber, with between 80%and 90% of houses being built with timber. In the US,and to a lesser extent in Australia, the use of timber is


St John’s in the City, Rotorua, incorporated trusses andarch windows from the former St John’s on the Hill in the

new church design.

affected by concern about the continued cutting of old-growth forests rather than new plantations, which havebeen slower to get started than in New Zealand.Nevertheless, timber is an established part ofAustralasian building culture and there is a generalacceptance of wood as a building material, especiallyin private building.

Despite this, timber is seen by some as a low-techproduct, which is difficult to work with and design forgiven its non-homogeneous character, great range ofspecies, and tendency to distort with changing moistureconditions. Also, complacency towards certain speciescan make timber unattractive to certain cultures. InScandinavia, pine is associated with high-qualityfurniture, yet in the UK, it is associated with cheapflatpacks (Hair 2002). The image of radiata pine inJapan was originally that of a low-quality species,suitable only for low-value packaging uses. When firstintroduced to the New Zealand building industry, sawnradiata pine was considered inferior to rimu, and it wasonly slowly accepted as a framing material. Althoughnow well accepted for structural applications bothoffshore and in New Zealand, it is more readilyaccepted overseas for appearance uses than in NewZealand. The experience to be learnt from NewZealand’s trade in the last 25 years is that, if a speciesis first used predominantly in the low-value sector ofthe market, it becomes difficult to convince thecustomer that it is suitable for alternative high-valueuses.

Architectural Awareness

With the exception of a small number of solidwoodhome manufacturers, use of exposed wood inarchitecture in New Zealand appears largely to consistof either exposed glulam beams, rimu finishing/moulding details, re-polished solid tongue and grooveflooring, or veneered cabinetry. This is due largely totimber, particularly pine, not being promoted to designprofessionals, and hence wood is under-rated by NewZealanders as an aesthetic material, compared to othernations which openly embrace wood for interior uses(Anon 2001).

There is a disparity between residential and commercialbuildings in the use of structural timber. This is blamedon the lack of support from the timber industrycompared with other industries, leading to lack ofdesign skills and supporting technical data for woodenmaterials (Nolan & Truskett 1999); however, theTimber Design Guide (NZTIF 1999) goes some waytowards alleviating this problem. Timber as a buildingmaterial of value has undergone a revival in many

32 Building Green

European and Scandinavian countries, mainly as areaction to post-modernist architecture, and due toadmiration of and enthusiastic response to modern

Left: Boutique timbers, sustainablymanaged, are becoming moreavailable in New Zealand. Woodenjoinery work can add warmth to homesand offices when incorporated into thedesign.

Below: Anglican Church, Cambridge.Wood was used extensively in both thearchitecture and the intricate detailsand fittings. Modern New Zealandbuildings have yet to display therevival of wood seen in recentEuropean architecture.

examples of wooden architecture for prominentbuildings.

Durability and

Maintenance of Wooden

Structures

Moisture Design

Moisture control and regular maintenance are the keysto long life of any building, and particularly woodenbuildings. Wood does not deteriorate with age alone

(witness the many wooden structures in Europe whichare hundreds of years old), but it is subject to insectand fungal attack if the moisture content is in theappropriate range.

Control of moisture from outside the building, withinwall and roof cavities, and inside the building itself, isimportant for health, comfort, and durability. This isachieved initially by careful design and constructionof the building, followed by appropriate use and goodmaintenance.

33

The most important item to get right is weatherproofingagainst rain and wind. There is no magic involved.Good architectural design taking into account localweather characteristics, combined with sensible useof cladding materials and attention to constructiondetails such as flashings and building wraps, will ensurea satisfactory result. The building envelope designphilosophy promulgated by the Canada BuildingEnvelope Research Consortium (BERC) requiresdesign consideration of the 4Ds (Deflection, Drainage,Diffusion, and Durability). A controversial aspect ofthis problem is whether solutions can be found throughsound building design that addresses the first three D’sor whether the fourth D, decay protection for durability,also requires attention. Kiln-dried radiata pine andother building materials are perishable if kept wet.However, radiata pine is a relatively easy wood speciesto treat with fungicides that prevent decay and mould.

Internal moisture problems are minimised by adequateinsulation, heating, ventilation, and maintenance of theexternal cladding. Compared with steel framing, theability of wood to absorb and desorb moisture incavities is an advantage in reducing the risk ofcondensation in framed walls, as is its thermalinsulation properties which reduce the risk of indoorcondensation forming along stud lines on interior walls.

Maintenance

Maintenance of the external envelope is required toavoid internal moisture problems due to rain waterentry or solar-driven condensation. Degraded paint canallow moisture penetration of external cladding which,when exposed to the sun, can drive the water into theinterior causing condensation problems. Exteriortreated wood products have a limited life also, andfence palings, posts, and other landscaping timbermembers need to be checked regularly, and may needto be replaced to avoid injuries from weaker rottingtimber.

Kiln-dried planed wood, used in situations where lowmoisture contents can be guaranteed for the life of thebuilding, is not required to be preservative treated. Suchsituations include interior wall framing and roofs butnot subfloor framing. Where there is a risk of elevatedmoisture contents, preservative-treated sapwood ornaturally durable heartwood of certain species may berequired. Such situations are those existing below floorlevel and timber exposed to the atmosphere such asdecking and pergolas.

Exterior cladding is required to be heartwood orpreservative-treated sapwood as, although only a 15-year life is required by the code, the risk of poormaintenance is high and deterioration of the claddingcan lead to deterioration of the structural frame.

Fasteners need to be chosen with regard to the corrosionhazards they face. Stainless steel fasteners withexceptional corrosion resistance are readily availableand are becoming increasingly used where thecorrosion hazard is high, such as near the sea orgeothermal areas.


Durability

Drying

Drainage

Deflection

Framing

PaperStucco

Illustrating the 4Ds

Wet zones such as kitchens and bathrooms requireventilation to prevent mould growth from steam vapour

condensate.

A well-maintained external cladding will prevent decay ofthe weatherboards, as well as interior moisture

condensation problems.

34 Building Green

Generally, the higher the Hazard Class the greater thelevel of preservative that is required. Three types ofpreservatives are commonly used in New Zealand:

• Boron salts for use in Hazard Class H1

• Light Organic Solvent Preservatives (LOSP)which may contain insecticides, such aspermethrin, for use in Hazard Class H1 orfungicides, such as tributyltin naphthenate(TBTN), for use in Hazard Class H3. LOSP havethe advantage that they do not cause the wood toswell during treatment and are therefore suitablefor the treatment of fully machined products orcomponents.

• Copper chrome arsenate (CCA) for use in allHazard Classes.

Due to increasing negative market perceptions of CCA,particularly in the USA, chromium- and arsenic-freeformulations have been developed as alternatives toCCA. Two that are registered for use in New Zealandare alkaline copper quaternary (ACQ) and copper azole(CuAz), but their use to date has been limited mainlybecause of their high cost relative to CCA.

Hazard Classification–––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

Hazard Class Exposure Service conditions Biological hazard–––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

H1 Inside, above ground. Protected from the weather Insect borers

and well ventilated

H2* Inside, above ground, Protected from wetting Insect borers and termites

H3 Outside, above ground Subject to periodic wetting Insect borers and decay

H4 Outside, in ground contact Subject to severe wetting Insect borers and decay

or in fresh water and leaching

H5 Outside in ground contact Subject to extreme wetting Insect borers and decay

or fresh water and leaching and/or where

the critical use requires a

higher degree of protection

H6 Marine environment Subject to prolonged Marine borers and decay

immersion in sea-water–––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

*Australia only

Where wood has natural durability it can be used for ashort time as an external cladding without coating.

Preservative treatment allows non-durable timbers to beused in a wide range of exterior applications.

Well-designed and maintained buildings in wood havean indefinite life, limited more by obsolescence thanby deterioration of the building fabric. At the end ofits useful life, a wooden building may be easilymodified, upgraded, or moved to a new location tostart life anew. Even buildings with brick veneercladding can be moved by dismantling the claddingbefore removal. Although more difficult than awooden-floored building, buildings on concrete slabfloors can also be moved.

Preservative Treatment

New Zealand radiata pine is not a naturally durabletimber and must be preservative-treated to extend itslife if used in situations other than fully protectedagainst the weather. In the latter case, kiln drying willprotect it against wood-borer attack if it remains at amoisture content below 16%.

New Zealand has adopted a Hazard Class system forspecifying the various levels of preservative treatmentfor different situations.

35

Mould and Decay in New Zealand

Houses

Recently a problem with leaky buildings in NewZealand has been noted by both the media andGovernment officials. Property damage (and associatedrepair costs) caused by wood-decay fungi, the potentialhealth risks associated with exposure to moulds, andthe lack of adequate compensation are causing the mostconcerns to homeowners.

There have been quite dramatic changes in buildingmaterials and practices over the last decade, which havecontributed to difficulties in constructing weathertightdwellings in a country with relatively high rainfall andwhere there is exposure to high winds. Such changesinclude the use of flat roofs, internal gutter systems,lack of eaves, monolithic claddings, sealants rather thanflashings, and a perceived decline in skills levels withinthe industry. As spelt out in other sections of thisBulletin, a holistic design approach is needed in anysustainable building development, and attention shouldbe given to the interaction of materials, particulardesign features, and methods of construction andinstallation, to mitigate the effects of leaking.

Research is being undertaken in a co-ordinated effortfrom several research providers and Forest Researchis playing its role in this process. Forest Research hasa long history of expertise associated with thefundamentals of building material properties,enhancement of their performance in the builtenvironment, and development of protection strategiesthat prevent decay and mould. By working alongsideother centres such as the Building Research Associationof New Zealand (BRANZ), the Building IndustryAuthority (BIA), and manufacturers of buildingmaterials and associated suppliers of performanceenhancing products and technologies, solutions willbe forthcoming. However, major effort will be requiredover the next 2–3 years if damage to the New Zealandbuilding industry is to be minimised and an enhancedbuilt environment developed.

Many building materials are at risk of deteriorationonce they become wet, health risks from moulds arepossible, and solutions to the problems are thereforerequired. The potentially toxic mould Stachybotryschartarum is known to occur in New Zealand housesthat have weathertightness problems, but the risk ofexposure to this mould needs to be weighed againstany risk associated with exposure to treatments usedfor protecting wood and other building materials frommould. Similarly, the risk of serious loss of value of

people’s investment in property also needs to beweighed against any risk associated with exposure totreatments used for protecting wood and other buildingmaterials from decay.

While the 1996 New Zealand Building Code removedthe regulatory requirement for all framing timber tobe preservative treated, it did define variousperformance life criteria (5, 15, 50 years), withassignments in each category being based on thefunctional importance of each. The Building Code thenlaid the responsibility with the supplier to define theproduct, purpose, use, limitations, and expectedperformance under given conditions. While kiln-drieduntreated framing timber is resistant to borer attackso long as it remains dry, there are difficulties inguaranteeing this performance for 50 years.Furthermore, in situations where there is persistentleakage of moisture, kiln-dried untreated framing willdecay and become less resistant to insect attack,making the long-term durability of the whole structureuncertain.

Achieving Durability through

Treatment

Anecdotal indicators are that timber is rotting prior todetection of any leak by the homeowner. Leaks canresult in major damage through decay before externalsigns are visible, such as surface staining or mouldgrowth, swelling of adjacent materials, or theappearance of water on interior surfaces or fittings.

To delay decay of untreated timber resulting from aningress of moisture, the Building Industry Authorityproposed as a temporary measure “until such time thatresearch is completed and NZS 3602 can be amended”,that framing timber that is used in areas of “high risk”to leaks be preservative treated to enhance durability(BIA News). High risk areas include bottom plates ofall framing, and exterior framing behind face-sealedcladdings that do not have a drained cavity. Treatmentis to protect the timber until such time that the leak ormoisture problem is identified by the owner, and fixed.This measure is seen as preventing the need for seriousrepair due to the rotting of framing timbers, wherefixing a leak is the necessary measure to prevent furthermoisture ingress.

Tests have shown that timber treated commerciallywith boron to Hazard Class H1 specification hassufficient fungicidal effectiveness to retard decay inwet radiata pine for a considerable time. In contrast,radiata pine treated with LOSP (permethrin) to the H1


36 Building Green

specification has no more resistance to decay thanuntreated timber. Unfortunately, there are problemswith kiln-drying timber treated commercially withboron; principal concerns are redistribution of thepreservative to outer zones of the wood and some lossesto the atmosphere from the timber surface.

Currently, the only option available in New ZealandStandards to impart decay resistance in above-groundsituations is treatment to Hazard Class H3specification. LOSP (TBTN or TBTO) is the preferredoption because there is no necessity to re-dry aftertreatment. However, there are some health and safetyand environmental concerns about the use of TBTNor TBTO for treatment of framing timber.

H1 Plus Concept

Responding to calls for comment to draft amendmentsto the Durability Section B2 of the Building Code, anumber of organisations, including Forest Research,proposed a level of treatment (“H1 Plus”) to confer“temporary” decay resistance to framing.

This was based on the following two premises:

(1) There is no current knowledge on preservationrequirements to guarantee for 50 years theprotection of framing timber which would besubjected to intermittent wetting throughout thatperiod, with concomitant accumulation of waterin the framing cavity. It is unlikely that an H3 levelof treatment, with the possible exception ofcopper-chrome-arsenic (CCA), would last thedistance.

(2) The most realistic option, therefore, is to determinea preservative treatment to protect framing fromdecay, should leaks develop, until such time asthe leaks are rectified. This assumes, however, thatcauses of leaks can be identified and permanentlyrectified. It would seem plausible that this periodof time could be up to 5 years, although in somecases it is likely that this period should be extendedto, say, 10 years.

Tests conducted at Forest Research showed that thefollowing treatments were candidates to meet therequired criteria:

• Boron at a minimum retention of 0.4% m/m boricacid cross-section retention and full sapwoodpenetration

• Tributyltin LOSP preservatives (TBTO, TBTN)at a minimum retention of 0.06% m/m Sn cross-section retention and full sapwood penetration

• IPBC at a minimum retention of 0.025% m/mcross-section retention and full sapwoodpenetration. It is recommended that this retentionbe an interim value until such time as moredetailed analytical information is obtained ondetermining the minimum levels required to conferdecay resistance.

The required boron retention can be achieved in kiln-dried gauged framing without raising the moisturecontent to levels which would require kiln drying aftertreatment, or which lead to unacceptable swelling ordistortion after treatment.

Weighing up the Risks of

Treatment

Perhaps the strongest argument in favour of treatingradiata pine with fungicides is that, should woodbecome wet, there is a high probability that the causecan be recognised and remedied before decay or mouldgrowth occurs. Damage to kiln-dried untreated radiatapine in buildings with weathertightness problems isdifficult to prevent because the window of opportunityfor fixing leaks and drying wood before decay and / ormould occurs is very small (3–12 months). Whilst moreresearch is required to select the best (and increasingly,more environmentally friendly) fungicide treatments,it is highly probable that cost-effective treatments (suchas H1 Plus Boron treatment) will protect wet wood formany years.

Some of the fungicides being considered for use onwood and other building materials would not beconsidered by pesticide registration authorities aspotentially more harmful than allowable pesticidesused for production of some organic food. This is notin itself a complete argument for use of fungicides onwood and other building materials, but it is anindication that acceptable, safe use of fungicides isachievable.

However, an increasing number of consumers seek alifestyle that aims to achieve an absolute minimum ofcontact with environmentally damaging or toxicchemicals. In recognition of this, Forest Research,partly in association with the wood preservationindustry, manufacturers of building materials, and othercentres of expertise, is conducting research that focuseson methods of decay and mould prevention thatoptimise and / or minimise use of fungicides. Otherwork focuses on use of naturally derived products andmaterials (chemicals) for control of decay and mouldon building materials.

37

Future Timber Preservation

During the past century, the mainstays of industrialwood preservation world wide were CCA, creosote,and pentachlorophenol/oil. Of them all, only CCA hasbeen used to any significant extent in the builtenvironment, mainly for treatment of timberfoundations and in exterior above-ground constructionssuch as decks and verandahs.

Because of real and perceived adverse health, safety,and environmental impacts of these preservatives, therehas been a rapidly accelerating introduction ofalternative wood preservatives. These are largely basedon copper with organic co-biocides. There have alsobeen moves to target preservative systems to specificend-uses.

Recent concerns about health risks to people exposedto CCA-treated timber, have seen restrictions on theiruse promulgated in the United States and Europe andthese will come into effect in 2004. These restrictionshave also been prompted by limited safe disposaloptions at the end of service life of CCA-treated timber.It is almost inevitable that similar restrictions, althoughless stringent, will be placed on their use in NewZealand in the near future.

Alternative Treatments

Copper Azole (CuAz) and Alkaline CopperQuaternary (ACQ)

Two non-arsenical copper formulations are registeredfor use in New Zealand — alkaline copper quaternary(ACQ) and copper azole (CuAz). ACQ contains copperand a quaternary ammonium compound (dimethyl-didecyl ammonium chloride), while copper azolecontains copper plus tebuconazole (with boric acid asa stabilising agent).

Retentions approved for use in the soon to be publishedNZS 3640 “Specification for preservative treatmentof timber” are shown in the Table below. Theseretentions have been based on performance data underNew Zealand and Australian conditions.

Only copper azole has been tested in New Zealand inabove-ground (H3) situations and to date performance

has been equivalent to that of CCA. However, ACQhas been tested in an above-ground situation inAustralia (Innisfail, North Queensland), whereperformance has been equivalent to that of CCA. Itwould not be unreasonable to assume that ACQ willperform at least as well in H3 Hazard Class uses underNew Zealand conditions.

Efficacy of preservatives which may be marketed asalternatives to CCA is not the only criterion which willdetermine their acceptance.

Current timber treatment processes, particularly thoseused to facilitate rapid throughput, are based almost(if not entirely) exclusively on CCA preservatives.

Questions arise as to the adaptability of these treatmentand post-treatment technologies to preservatives otherthan CCA. There is also the question of plantmodifications to accommodate use of alternatives toCCA. Copper azole is marketed as Tanalith® E byKoppers Arch Wood Protection (NZ) Ltd, and ACQ asACQ Preserve by Osmose New Zealand Ltd.

Locked-in-Boron™

Most boron-based wood preservatives have limited usebecause they are leachable from wood when exposedto severe and continuous wetting. Forest Research hasrecently developed, tested, and patented “Locked-in-Boron™”. When wood treated with a particularLocked-in-Boron™ chemical becomes wet, boron isunlocked and slowly released, protecting the woodfrom fungal establishment. However, in the event ofincipient decay which results in lowering of the woodpH through fungal attack, a pulse of boron would beunlocked, limiting the decay. The Locked-in-Boron™product therefore has potential to provide both abackground level of protection and also prevention ondemand. Commercialisation feasibility studies forLocked-in-Boron™ are in progress.

Further improvements are being made to these andother preservative technologies, to ensure theperformance of timber is not compromised by a lackof inherent durability, or by environmentally andsustainably unsound preservative practices post-harvest.

Preservative Retentions (% m/m OD wood) for each Hazard Class–––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

Formulation H1 H2* H3 H4 H5 H6–––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

CuAz (Cu+triazole) N/A N/A 0.27 0.46 N/A N/A

ACQ (Cu+DDAC) N/A 0.35 0.35 1.02 1.35 N/A

CCA (TAE or element) 0.04 As 0.32 0.37 0.72 0.92 0.40 Cu–––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

*Applicable to Australia only


38 Building Green

Wood has been used as the major construction material in the great

variety of house styles in New Zealand over the past century

39

Environmental

Performance

Embodied Energy

Embodied energy is the direct and indirect energy usedto extract, manufacture, transport, and install materials.Manufacturing wood products is renowned forrequiring considerably less energy than manufacturingproducts from alternative competing materials. Thetable below illustrates the energy required to produce1 m3 and 1 tonne of timber, steel, and concrete.

As both the Table and the Diagram that follow show,wood as a building material results in less energy usageand CO2 emission to the atmosphere than othermaterials such as aluminium or steel. However, oneneeds to consider the total embodied energy to do a

particular structural job, e.g., support 1 tonne in tensionover 1 m. This will give a different picture as a lowerweight and volume of steel are required to do a givenjob than for timber; however, a greater weight andvolume of concrete are required (see Table on p. 27).

More recent embodied energy data from Alcorn (1998)showed reductions in the process energy of 9% for steeland 39% for concrete. There are critical environmentalfactors in cement and concrete manufacture over andabove embodied energy, however, in the form ofemissions of carbon dioxide, nitrous oxide, and sulphuroxides. A shift toward greater use of wood inconstruction would therefore result in a small butsignificant reduction in CO2 emissions. These studiesdo not, however, include the energy requirements ofmaintenance, rehabilitation, and demolition over thefull life-cycle of the building.

Royal and Sun Alliance Centre

The Auckland Royal and Sun Alliance centre has

recently won two awards for energy efficiency.

Recognised by the UK Royal Institute of Chartered

Surveyors (RICS) in 2001 for best practice standards

in space, energy efficiency, and operating costs, this

174-m-tall building has over 40 storeys and is

currently the tallest commercial New Zealand

building. It also was highly commended in the

IRHACE/EECA EnergyWise Design Awards in 2001.

However, unlike other green building initiatives, the

major incentive for construction was to yield a healthy

return on investment to the developers and owners.

Although tenants focus on aspects of performance

other than energy efficiency, a low operating cost for

the tenant is obviously an advantage. Green

buildings (particularly commercial) must also be

economically viable. The strength of the building’s

design is its practical compromises. It offers bicycle

facilities, but also provides car parking. The building

is not designed passively, but prevents solar heat

from building up through low emissivity glass

windows, and has a mechanical but very efficient

heating, ventilation, and air-conditioning (HVAC)

system to meet the exacting requirements of the

performance specifications. The annual HVAC

energy consumption of 82 kWh/m2 of occupied space

is well below the benchmark by the NZ Property

Council of 140 kWh/m2. Although the building is not

a wooden structure, the foyer interior fit-out makes

good use of wooden components to add to the

pleasant environment.

Source: Energywise News, EECA, 2002


40 Building Green

Life-cycle analysis (LCA)

LCA is used to evaluate and compare differentproduction systems and products from cradle to grave;typically included are not only embodied energy, butalso raw material acquisition, distribution, use, anddisposal (Gifford 2001). The life-cycle of woodproducts involves five discrete phases, namely:growing and harvesting the tree, processing the logsinto wooden components, fabricating the end product,using the product for a certain period of time, and finalwithdrawal of the product from useful service intoreuse or disposal.

New Zealand has completed around 15–20 LCAstudies that relate to forestry and constructionmaterials, with a further 20 relevant studies identifiedfrom international literature. The most comprehensiveassessment of these for a New Zealand wood product(Gifford et al. 1998) found the most significantcomponents of the production life cycle for framinglumber which contribute CO2 emissions are the

harvesting and processing stages, and energy and waterare the major resource inputs used to produce framinglumber.

Several LCA studies from around the world have alsoassessed the environmental performance of wood as arenewable material, utilising LCA software packagessuch as ATHENA (see Appendix 3). The CanadianWood Council (2000) concluded that wood is anexcellent, environmentally friendly, framing material.Wood construction products were found to releasefewer air- and water-borne contaminants than metaland concrete, and to consume fewer natural resources.Richter & Sell (1993) discovered that timber framingcould be recycled with fewer land filling burdens,whereas the alternatives required much more energyto demolish and dispose of. Marcea & Lau (1992)showed that wooden structures required less energyfor production and were associated with smaller CO2

emissions than brick and tile, concrete, and steelbuildings.

Energy required for, and carbon released from, the manufacture of construction materials used in

New Zealand.

–––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

Material Energy Density Carbon released Carbon Net

-------------------- (kg/m3) ------------------------- stored carbon

(GJ/t) (GJ/m3) (kg/t) (kg/m3) (kg/m3) emitted

(kg/m3)–––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

Treated wood 2.4* 1.2 500 44 22 250 –228

Glue-laminated timber 9 4.5 500 164 82 250 –168

Reinforced concrete 3.1 7.3 2400 76 182 0 182

Structural steel 59 448 7600 1070 8132 15 8117

Aluminium 145 362 2500 2530 6325 0 6325–––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

Source: Buchanan (1993) Wood Design Focus 4(2)

* Typically energy used to produce 1 oven-dried tonne of kiln-dried framing ranged between 6.6 and 8.1 GJ (Gifford et al.

1998)

Net carbon emissions from production of some building materials

41

In an LCA by Werner et al. (1997) wooden door frameswere environmentally superior to steel ones as steelframes contributed almost three times more globalwarming potential (GWP) than the solid wood framesand consumed more total energy.

In-use energy performance is difficult to quantify on amaterial basis, as space-heating requirements ofbuildings vary greatly depending on design, thermalinsulation, geographic location, and desired levels ofcomfort. The amount of energy required to heat atimber home compared to alternative materials is sodependent on these other factors that usefulcomparisons are difficult.

See Appendix 3 for more information on Life-cycleAnalysis systems.

Waste Minimisation

Construction waste usually exceeds municipal wasteon a weight per capita basis in most Western cities,and there is a huge incentive to reduce this as dumpingcosts and prohibitions on certain waste streams increase(Anon 1999). Economical and environmental pressuresare now forcing a change in dumping practice, and anumber of initiatives have been introduced to reducethe amount of waste wood going to landfills fromconstruction processes. These include optimising gradelengths when cutting componentry, prefabricatinghouse components and systems in a factory utilising

62199

Athena study

Comparative LCA of Residential Housing

In 1999, the AthenaTM Sustainable Materials Institute undertook a partial life-cycle environmental assessmentof three alternative 2400 sq ft house designs with concrete (insulated concrete form), steel (light frame),and wood (I-joists and softwood lumber) as the major systems components. The study investigated theresource extraction through to on-site construction stages of building the three houses, which had similardesign features, with the same exterior aesthetic, divided living area, and size for a Toronto market. Withcommon elements excluded, the institute used the ATHENATM LCA tool to determine the following casestudy results:

Wood design Steel design Concrete design––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

Embodied energy (GJ) 255 389 562

Global warming potential (kg CO2 equivalent) 62 183 76 453 93 573

Air toxicity (critical volume measure) 3 236 5 628 6 971

Water toxicity (critical volume measure) 497 787 1 413 784 876 189

Weighted resource use* (kg) 121 804 138 501 234 996

Solid wastes* (kg) 10 746 8 897 14 056–––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

* These have not been adjusted for comparative densities, and would differ significantly on a volume basis.

Source: Trusty & Meil (1999)

Sustainably managed plantation pine is used for exportfurniture manufacture.


42 Building Green

An abandoned Californian warehouse retrofitted into loft apartments

optimisation and mass production techniques,and reusing wood — both interior fitouts andstructural — from demolished buildings.

In the end, if demolition or deconstruction isnecessary, many wooden building materials canbe recycled or reused. A flourishing trade existsin dismantling buildings containing high qualityheart native or imported timbers. The salvagevalue of older timbers (particularly nativespecies) from retrofitting and demolitionprojects has enabled trade in recycled systems(particularly doors, windows, and trusses), aswell as providing planks (from flooring,cabinetry shelves, and cladding) to be reworkedinto new high-value products. The salvagedtimber is then reused for furniture or othersuitable building applications.

Left: The warehouse prior toretrofit.

Right: New loft apartmentswith existing timber beams.

Prefabricated “pre-cut” frames are assembled on a jig.

43

Demolition treated timber is still allowed to be dumpedin landfills; however, it is an industry aim to recycletreated timber — e.g., redundant telephone and powertransmission poles get recycled as either landscapingor agricultural fences.

Prefabrication of frames and trusses offsite, as well asthe factory production of fingerjointed products, hasreduced the number of small off-cuts being sent viaskip to landfill, as these are often resold as firewood,or burnt as boiler fuel. This process also allowsoptimisation through mass-produced items.

With over two million cubic metres of readymixconcrete being used in New Zealand construction peryear, a large volume of waste concrete is sent to thelandfill as builders’ waste but technologies are available

Deconstruction of thehall at Ohope allowedthe recovery of heartrimu timber, andsubsequent manufactureof fine furniture.

to reclaim sand and aggregates from concrete beforesetting (Park 1997, 2000). Concrete aggregates andrecycled steel are the most common forms for re-using building waste. Using crushed waste concreteas aggregate, and reusing unset aggregate are twoways to reduce environmental impacts from concrete,but there is still a disposal problem to contend with.


44 Building Green

The previous sections highlight the potential for anincrease in the use of timber and wood products inmeeting the demands for sustainable building. As morework on embodied energy and life-cycle analysis iscompleted and disseminated in user-friendly packages,the merits of sustainably produced timber will becomemore apparent.

Increasingly, public sector organisations and privatecompanies are looking for architects and builders witha credible track record in sustainability. However,builders and architects need time to consider newpractices, source new materials, and gain experiencein new methods. Within current market conditions thereis little extra money or capacity to carry this out,although the costs of building sustainably are notnecessarily higher and may well be less with, forinstance, more efficient waste management practices.Once there are good examples of sustainable practicesin the general market place, both consumer andindustry are more likely to adopt these for themselves.

This section provides case studies from New Zealandand overseas which illustrate how timber and woodproducts are being used in a variety of sustainablebuilding projects.

Built Green: From Vision to Reality

Public Buildings

Glencoe Visitor Facilities, Scotland

Glencoe lies in highlands of Scotland. Famous for itsrugged wilderness and a notorious massacre ofMacdonalds by the Campbells, the area attracts visitorsfrom all around the world.

The visitor facilities at Glencoe include a café, kitchen,shop, toilets, interpretation centre, and education room.Boardwalks connect these with administrationbuildings, storage, and on-site staff accommodation.A steel framework raises the whole complex off theground, reducing environmental impact and allowingventilation beneath the floors.

Timber-framed with vertical board and batten wallcladding, the entire complex is made from locallygrown wood. None of the timber used is treated withpreservatives. European larch (heartwood) is used inall boards and supporting battens, and the boards areface-sawn with planed edges. (Whether to plane or sawthe cladding boards was a moot issue. Planing canreduce moisture ingress by reducing the amount ofsurface presented to the atmosphere. Conversely, sawnsurfaces permit moisture to evaporate much morereadily, and can reduce the time boards spend saturated.An open surface texture also better protects timberagainst UV degradation and affords greater surfacemovement without the timber cracking — a commoncause of decay.) All boards are fixed so that they cupoutwards and shed water down, rather than around andbehind, their edges. No coatings of any sort have beenused.

Screwing the boards proved too expensive and so eachis nailed, with force carefully gauged to prevent nailheads penetrating too far into the timber’s surface(ideally, they should be flush with the surface to avoidcreating mini-collection points with exposed end-grain). Screws would have facilitated ease ofreplacement of boards, but nailed connections wereaccepted by the design team once it was agreed thatboards would only be removed when they wereunlikely to be useful for other applications. Nails areapplied centrally, allowing for any amount ofmovement to either side, thus avoiding any crackingcaused by fixed connections working against thetimber’s natural movement.

Differential weathering between boards is adisadvantage of vertical cladding — the lowest 150–300 mm can suffer splashback but higher areasprotected by eaves stay in good condition. To avoidreplacing whole boards when only their lowest partsare in poor condition, a detail was developed using a150-mm horizontal board to take the brunt of theweather whilst the vertical boards above remain in goodcondition.

45

Untreated European larch boards have also beenused to clad the roof. Although this is contrary torecommended practice in Scotland and Norway, thewider environmental remit of the building precludedthe use of preservative-treated roof boards. Thedesigner and client accept that the roof timbers willrequire regular maintenance and have detailed itaccordingly.

Source: Davies, I.; Walker, B.; Pendlebury, J. 2002: “TimberCladding in Scotland”. ARCA publications

community, and developers. The school dominates thesite. Its orientation also helps to maximise passive solargain and to reduce over-heating in summer.

The school is triangular in shape with six classrooms,resulting in high wall-to-floor ratios. The externaltimber-framed “breathing” wall is filled with recycledpaper for insulation. An efficient condensing boilerprovides underfloor heating. It has a living “green”roof planted for insulation with a sedum mat, filters,and drainage membranes. The flooring is made ofbamboo and the whole building is clad with untreatedcedar boarding. All the materials were assessed forquality, life-cycle, and maintenance costs. Recycledmaterials were used where possible; work tops weremade from plastic bottles, and the entrance mats fromlorry tyres.

Both the pupils and the design team appraised theproject and the design process on completion. Withmore funding the project could have been furtherdeveloped and the principles of sustainabledevelopment refined, but it remains an example of whatcan be achieved within a standard local authoritybudget and teamwork. The project has become a

Primary School, Notley Green,

Essex, England

Notley Green primary school has won renown for itsinnovative design and sustainability credentials. Itssuccess is due to a visionary local authority and acarefully assembled group of professionals with acommitment to integrated team working.

The clients, Essex County Council, held a designcompetition for a prototype school that embracedsustainability objectives. The project was alsoconditional on the costs being in line with thosenormally expected for a project of that size.

Essex County Council gave the team freedom toexplore options and depart from the original designbrief, provided that the outcome was sustainable andwas acceptable to the Council. The architects, AllfordHall Monaghan Morris, were permitted to depart fromstandard practices and allow service engineers todesign equipment.

The design process itself was built around consultationbetween local authority planners, teachers, the local

Non-preservative-treated roofing will require regularmaintenance

Locally grown larch was used throughout thedesign


46 Building Green

multiple award winner, compiling an impressive listof accolades.

Stenurten Kindergarten,

Copenhagen

In 1999, Kommune København decided to build a newecological kindergarten, and brought in eco-experts forthe development. After 6 months, a small site (800 m2)became available but, as it was just 15 m wide, a majorrethink of the proposed design was necessary. The sitewas located between a large church and a road, andalso had two ex-war bombshelters within itsboundaries.

The chosen design utilised maximum solar gainsthrough a glass facade, angled to catch maximumwinter sun, and the building was divided into threezones: A “conservatory” for preheating air into the mainliving area (Zone 2), and a wet area for washroomsand toilets, which had little natural light.

The double-glazed windows of Zone 1 use passivesolar heat to preheat air for Zone 2. The floor of Zone 1consists of a polystyrene slab, over which sand waspacked, and then recycled wooden bricks from an oldgymnasium were used as the top layer. This gives ahigh level of insulation.

In summer, Zone 1 gets very warm, and the glass facadeand ceiling skylights can be opened to prevent hot airfrom entering Zone 2. Zone 1 also admits a great dealof natural light for both Zones 1 and 2. Cool air entersat the base of Zone 1, and is heated by the sun beforeentering Zone 2 at the top of the interconnecting wall.In winter, a steam pipe at the base of the wall with agrill vent heats incoming air from Zone 2. The heatedair recycles out into the cooler Zone 1 through the

Building in brief

Project details: Start September 1998; finish September 1999.

Project Cost: £1,350,000

Awards: RIBA Award for Architecture 2000, RIBA Sustainability Award 2000, Design Council

Millennium Project, Royal Fine Art Commission Trust School Building of the Year2000,

CIBSE Award for Innovation, Construction Industry Award 2000, Civic Trust Award

2001.

Client: Essex County Council, United Kingdom

Developer: Countryside Properties

Architects: Allford Hall Monaghan Morris

doorway, and is recirculated back to Zone 2 once heatedby the sun. In this way, the temperature of Zone 2 ismoderated at between 21 and 24°C. Zone 2 also hasunder-floor heating, and a skylight in the centre of thebuilding. Zone 3 contains toilets, laundries, andwetroom activities. The airflow allows moisture to beremoved from these areas without circulating back intothe other zones. It is heated by a radiator.

Wood is not often used in Denmark for building, andZealand has very few resources for building. For thisproject, the outer walls were constructed from timber,and the interior inner walls from clay brick.

However, there is much evidence of the non-structuraluse of wood throughout the building. Children’s

Sources:http://www.teachernet.gov.uk/sbnotleygreen (22 May 2002)

“Celebrating Innovation”. Centre for Architecture and theBuilt Environment, London. www.cabe.org.uk

Ergonomically designed chairs makeuse of wood-bending techniques.

47

extremely sensitive location. The three phases ofdevelopment increased in ecological sophisticationleading to a low-impact resort development based ona zero waste model.

Timber was chosen as a building material due to itslightness, softness, and its natural feel. The architecturerespects the forest and coastal environment. Thebuilding itself was designed to weather and age ratherthan wear.

The use of timber as a renewable, low-energy material,sits within the overall design concept of the buildings.It embraces energy-saving solar chimneys, solar hot-water heating, and control of solar gain through louvresand pergolas.

Phase 3 has a concrete-insulated ground floor with afull timber building structure and light roof. All thetimber used is sourced from forests certified by theForest Stewardship Council and where possibleobtained locally. All framing is untreated pine andlocally sourced macrocarpa. Other uses of timberinclude:

furniture, door jambs, beams, and even the base ventslats are all timber, with timber flooring throughoutthe building. All materials were sourced locally, withmost left in their natural state. Because of this use oftimber, the building has a warm feeling to it, despitethe fact that many areas have no additional colourdecoration, and earth-tones predominate throughout.

The roof is constructed of 300 mm of linen insulationover a layer of polystyrene. Sedum greenroofing wasused also to filter the rainwater run-off, which is usedby the kindergarten for non-drinking purposes. Thesedum delays peak water flows, cools the roof insummertime, removes carbon from the inner city, iseasier to maintain than paint because there is no harshsunlight damage, and is more aesthetically pleasing.Solar panels are used to heat the water for washingnappies and soiled clothing in the daycare centre whichuses city grid power for electrical supply.

The centre has been in operation for 3–4 months with80 children and 20 teachers. The construction cost 15%more than the normal costs for such a building, butsaves money in the long term on thermal heating, anddomestic water heating.

Architects: Arkitektgruppen Aarhus

Commercial Buildings

Punakaiki Eco Resort, Punakaiki,

South Island, New Zealand

This project was designed to meet the standardsnecessary for five-star tourism accommodation in an

Sedum is used to filter water and insulate the roof. Woodis used for the exterior cladding.

The warm wooden floor contrasts with the cooler brickwalls. Timber jambs and skirting reflect this also to good

effect.


48 Building Green

• Eucalyptus fastigata on the external pergolas,louvres, and structures, and plywood (a low-cost product) on the exterior, under the eaves,and stained, alongside Eucalyptus battens.

• Inter-tenancy walls have double framing tocomply with fire and sound insulationrequirements, lined with two layers of Gibboard on each side.

• Inter-tenancy floors are sound- and fire-rated,and use Tri-board as the flooring sheeting ontimber floor joists.

Above: Eucalyptus fastigata pergola eaves duringconstruction.

Left: The building was sited to nestle into surroundingnikau bush, but allow sea views.

Building in brief

Designers: Common Ground Urban Design & Architecture

Principals: Hamish Kilford-Brown, James Lunday

Town Planning: Common Ground Urban Design & Architecture

Landscape: Land Arch Limited

Engineers: O’Loughlin Taylor Spence

Fire Engineer: Cosgrove Major

Electrical Engineer: Cosgrove Major

Client: Punakaiki Villas Limited

Builder: Chris Yates

Stage 3: 12 units

Budget: $850,000.00 approx

Eastwood Road Clinic, Remuera,

Auckland, New Zealand

This orthopaedic clinic in Remuera, Auckland, wasdesigned both to reduce environmental impact and toembrace energy conservation. The building is raisedon a concrete and steel plinth, allowing parkingunderneath. The site had a natural slope and the aimwas to minimise the amount of excavation necessaryto establish the foundations. The flooring is made from

certified plantation Eucalyptus and the building frameis a combination of plantation pine and steel (steel wasused because of the large spans in an open plan setting).

The interior is Gib board with large feature walls ofoiled plywood panels. The external cladding is mainlyplywood (stained with negative detail) and largeexpanses of glass. The rear “lean to” box is in cementsheeting panel which plays against the natural timberpanels on the exterior. The large north-facing glazed

• Timber features as inside walling to enhancethe solar chimneys.

• Vanity tops and bathroom seats are made ofplywood. Suitcase racks use plywood withstainless steel strips.

• Composite timber products are used for thejoinery and cabinetry.

49

wall provides high levels of daylight, and heat gain iscontrolled through louvres and, naturally, by matureoaks on the property.

The architects commented, “You have to work hard atsourcing F.S.C. timber, especially higher quality

finishes for joinery and flooring. There is littleinformation about the sustainability aspects of non-pine plywood — meranti, cedar, etc. — as to whetherthey are F.S.C. or not”.

The end result has enhanced company profile, reducedenergy bills, and above all created an attractive workingenvironment for staff.

Building in brief

Designers: Common Ground Urban Design & Architecture

Principals: Hamish Kilford-Brown, James Lunday

Landscape: Common Ground Urban Design & Architecture

Town Planning: Common Ground Urban Design & Architecture

Engineers: Harris Consulting

Client: Eastwood Orthopaedic Group

Builder: Macharr Developments

Budget: $750,000.00

Basement area 495.2 m2

Ground floor: 283.9 m2

Mezzanine: 75.6 m2

Common Ground Urban

Design and Architecture —

Auckland.

General perspective on

sustainability and timber.

“Timber is an ideal construction material

to create low impact, lightweight

buildings suitable for the Australasian

climate. Whilst difficulties can occur in

relationship to sound proofing and fire

proofing, we have demonstrated that

these can be overcome (economically)

with appropriate detailing. We have

designed commercial, tourist, and

apartment buildings using timber framing

without problems. The art of architecture

is the balance of form, function,

aesthetics, and sustainability.”

An attractive environment for both staff and patients.


50 Building Green

Green on the Grand (Office

Building), Ontario, Canada

Completed in 1996 by Ian Cook, this building isregarded as one of the leading examples of sustainabledesign in Canada. As a sustainable low-rise officebuilding, it meets the requirements of Canada’s C-2000programme, consisting of four major criteria forbuilding design: energy efficiency, minimalenvironmental impact, occupant health and comfort,and functional performance. Located above the GrandRiver, the building maximises passive solar gainthrough careful siting, with water and electricityconsumption almost 50% less than would be expectedfrom an equivalent conventional building. The buildingconcept embraced the use of low embodied energy andrenewable or recycled materials.

The building support structure is composed of small-dimensional timber and engineered wood products. Toavoid problems of shrinking and twisting from anydimensional instability, engineered wood productswere used as the main structural members of thebuilding. These glued wood products are extremelystrong, dimensionally stable, and cost-effective, andhave minimal effect on indoor air quality (phenolformaldehyde glue was used, as opposed to ureaformaldehyde glues, and most members are locatedoutside the vapour barrier). They are also widelycommercially available. The main columns are 125 ×175-mm laminated strand lumber members spaced upto 6.7 m apart. The exterior first floor walls use 38 ×89-mm laminated veneer lumber as the supportmembers. Laminated veneer lumber beams runhorizontally to connect the columns together to providea rigid support structure.

Wood was chosen as the framing material as it is arenewable resource with low embodied energy. It alsowas relatively cheap, stores carbon, and minimisesthermal bridging.

The subfloor between the first and second levels isconstructed of 400-mm-deep wood l-joists spaced at600-mm centres. The joists are covered on theunderside with 16-mm drywall for a 3/4 hour fire rating.The tops of the joists are covered with 19-mm orientedstrand board and a 19-mm topping of gypcrete forsound dampening.

The roof is constructed of 450-mm wood l-joists forthe steep pitch, insulated with 350-mm mineral woolbatts spun from 50% slag waste. Wood trusses madefrom small-dimensional timber were used for theshallow pitch, with flat ceilings insulated with 450-mmblown cellulose.

The basement walls and slab-on-grade floor are pouredconcrete and insulated. The floor between the basementand first floor is a hollow-core concrete slab for soundand fire protection.

Finishes and Furnishings

Choices made in office interior design, and theselection of furniture and equipment, have significantenvironmental and indoor air quality impacts. Woodtrim was made from fingerjointed woods, thus makingthe best use of timber. Some of the internal doors wererecycled from an older renovated office building.Formaldehyde-free particleboard was used for muchof the cabinet work in the building. Most of thefurniture was reused, refinished, or made from steelfinished with powder-coated solvent-free paint.

Green on the Grand usedlow embodied-energymaterials, and emphasisedrenewability andrecyclability in materialschoice.

51

Omicron Consulting, Office

Development, Canada

This innovative office project is being built under theLEED™ (Leadership in Energy and EnvironmentalDesign) certification programme. LEED, launched in1995, has become a mechanism to reward green andenvironmentally sensitive design and construction inthe United States. It is managed and administered bythe US Green Building Council (www.usbgc.org).Credits are awarded for using materials that arerecycled, with local or regional importance, fromrenewable sources, or salvaged from elsewhere.

Materials to be used in the Omicron office developmentare being selected largely on the basis of LEED criteriaand for their sustainability and aesthetic merits. Theproject, which is still in the development phase, willuse local engineered wood products — either paralamor glu-lam for rafters and purlins. Paralam is anengineered wood product made from wood wastecollected from the mill and combined with a bindingagent. Glu-lam, made from second-growth Douglasfir, is laminated to form larger structural members.Other wood products to be used include locally grownmaple, with a formaldehyde-free MDF or MDFwithout any veneer. Most of the timber to be used inthe project is accessible from local plantations. Theability to obtain FSC certified timber in Canada hasbeen a problem for designers and architects. To dateonly one LEED project has managed to successfullyreceive a credit for using certified timber (KevinHanvey pers. comm.). British Columbia is currentlypreparing its own local version of LEED, which willeventually be combined with a national LEED Canada.

Large Commercial

Buildings

Large commercial buildings have been identified by arecent UNECE market review on forest products asbeing an under-utilised opportunity for timber use(UNECE 2001). The statement is echoed by GregoryNolan from the Timber Research Unit at TasmaniaUniversity, who considers that this is hindered bytimber being maligned as an unreliable structuralmaterial by a significant proportion of Australiandesign professionals (Nolan undated). In New Zealand,too, it is acknowledged that using timber structurallyin commercial buildings suffers from being regardedas non-traditional.

Olympic Exhibition Centre,

Sydney, NSW, Australia

For Sydney’s “Green” Games of 2000, the OlympicCo-ordination Authority actively pursued ecologicallysustainable development principles, in line with theFederal policies. In particular, they sought theconservation of species and natural resources, and thecontrol of pollution. The Olympic Exhibition Centre,designed as part of the new Sydney Showgroundredevelopment within the Homebush site, is one ofthe buildings in which, at concept design stage, it wasdecided that timber would be used as a structuralelement and finish, because it was a sustainablebuilding material. F11 radiata pine was specifiedbecause it was a plantation material and, in thisinstance, was sourced from Australia, eliminating thepossibility that native forests would be depleted.

Located adjacent to the Olympic Park railway, at thesouthern edge of the Showground precinct, theOlympic Exhibition Centre has two main sections —a 97-m-span dome, and a hall. The design for thebuilding has a simple partition; the dome provides thearena, and the hall the venue for exhibitions, concerts,banquets, displays, conventions, or staged events.

Structural Description

The dome is a conventional geodesic structure, withglue-laminated radiata pine used in the compressionmembers and steel used in the struts. As an architecturalexpression, the timber elements are detailed to establishpattern, and provide colour and a layering of thestructure. All of the other elements are then scaled tocomplement the use of timber. The elements meet atcomplex fabricated steel connection nodes. To fix tothese nodes, each end of the timber beams has eightcouplers and a threaded anchor rod is set into thelaminated timber with epoxy resin. To resist theincreased loads towards the base, the timber sectionprogressively increases from 800 × 130 mm in the topcircle of the dome to 800 × 230 mm at its base.

The Exhibition Hall was designed and constructedusing glulam, specified by the architects Anchor,Mortlock and Wooley for its unique aesthetics, costeffectiveness, and environmental credentials.

It has been designed so that it can be divided into sixseparate pavilions by operable walls. The hall’s roofform derives from the need to give each of thesepavilions some distinction, while supporting themoving walls and retaining a roof structure in sympathyto that of the dome. Again, glue-laminated timber


52 Building Green

beams are combined with steel struts to arch down fromthe peak of the roof to the steel support columns. Hereat the perimeter, the steel and timber elements form atruss in the plane of the roof. This takes the horizontalthrust from the arched form and resolves it throughthe major transverse tension ties of the operable wallsupport lines.

To ensure quality and consistency for such a large andpublic project, a rigorous quality assurance programmewas put in place. Each laminate and each fingerjointin the beams was individually proof-tested before thebeams were assembled, and a length was cut from eachbeam and subjected to a cleavage test. Further, a sampleof every batch of epoxy used in setting the boltingcouplers was retained and tested.

Residential Housing

Co-operative Housing Association

of Aotearoa/New Zealand

(CHAANZ)

CHAANZ is a not-for-profit umbrella organisationbuilding affordable, good quality, and re-locatablehousing for those most in need. All its operations areunderpinned with the concern for sustainability, whichis viewed as having three interlocking threads ofenvironmental protection, economic development, andsocial development.

The association uses, as far as is practical, low-energymaterials which are in surplus in New Zealand, andwhich are part of New Zealand’s renewable resources,i.e., wood! At the same time, attention is given to designto reduce financial as well as resource costs, e.g., using:

Olympic Exhibition Building, Sydney, built 1997–98

Architect: Ancher, Mortlock and Wooley

Engineer: Ove Arup

Builder: Theiss Construction

Owner/Trustee: Royal Agricultural Society

Detailing of the roof structure of the dome at theOlympic Centre.

Constructing a prefabricated wall panel at CHAANZ.

53

• Driven wooden piles

• Radiata pine framing using, where practical,designs incorporating only one size, 100 × 50 mm,thus reducing or eliminating waste

• Plywood — Shadowclad or similar high-qualitylong-life material

• Onduline roofing.

The framing is dimensioned using specificallydesigned cutting and panel jigs, with the panelisedcomponents being assembled on-site. The system isbeing extended to factory-finished modules which canbe assembled on prepared sites.

This approach to sustainability incorporates the aimof self-financing housing delivery systems. Thephilosophy of the association is to take housing out ofthe market and conventional debt cycle, to reducehousing costs, and recycle monies back into the localeconomy. Where possible CHAANZ aims to contributeto the development of stronger local economies throughsupporting local forestry products, e.g., PanguruEcological Village, Hokianga. This is a partnershipproject as laid out in the UN Habitat 11 (SustainableHuman Settlements in an Urbanizing World)declaration.

Its aims are to:

• Alleviate poor housing conditions (e.g., in theHokianga area)

• Contribute toward regional development by:

* Developing the local economy

* Beginning a process of re-population

• Make net contributions to the regional and nationaleconomy by building local infrastructure support

systems, so lessening the need for both futureinfrastructure investment and welfare expenditure

• Create an energy-neutral way of life which doesnot contribute to global ecological degradation.

The housing would use sustainable building principlesand design, including renewable resource buildingmaterials, efficient wood-burning stoves, and thecreation of woodlots for coppiced firewood. On-goingresearch includes the development of a woodenwindow and door system using sawn timber.

Van Midden House – An

“Affordable” House, Scotland

Gõkay Devici Architects

Designed and constructed as a result of a researchprogramme on “Affordable Housing Projects” at TheRobert Gordon University, the Van Midden houseprioritises affordability and ecological sustainabilityand demonstrates that truly “affordable” housing neednot be inconsistent with good, responsible, sustainabledesign. The basic design concept rests on the costsavings which arise from the utilisation of a simplegeometric plan form to maximise the space/enveloperatio. Further savings were achieved by centralisingthe living space, thereby minimising the circulation,and by using a simple modular structure.

The structure and cladding materials are predominantlyof timber, and the resultant savings in weight alsoconsiderably reduced the cost and work involved inthe substructure. Lightweight timber ‘I’ beams wereused for the wall and roof members, a strategy whichpermitted the inclusion of 220- and 300-mm recycled

A completed CHAANZ house design.


54 Building Green

newspaper insulation in the walls and roof respectivelyand helped reduce the house’s energy requirements toa minimum. The wall cladding is homegrown Norwayspruce and this lightweight and very cost-effectivecladding material — used in combination withlightweight corrugated steel roofing — further reducedthe construction costs. The house has deeper thannormal eaves in order to shelter the external cladding.

Materials throughout the six-bedroom house wereselected for their low embodied energy and, whereverpossible, recycled materials were used. The majorityof the materials were sourced locally, with theembodied energy estimated at 1.4 GJ/m2 compared to6.5 GJ/m2 for a traditionally-constructed dwelling. Byusing a breathing wall construction, the need for vapourbarriers was eliminated. The wall and roof panels were

designed to be prefabricated and, with a trussless roofstructure, the resulting space was freed up to provideadditional storage and play space.

In the context of external timber cladding, this houseis notable both because it uses lightweight timbercladding and structure as part of an integrated designapproach, and because the cladding is made fromNorway spruce. In common with standard practice onthe west coast of Norway there has been no attempt toremove the sapwood and the timber has not beenpreservative-treated. The cladding, however, iscarefully detailed to promote drainage and ventilationand has been given a water-repellent surface coating.This approach appears to offer considerable potentialfor the use of homegrown Sitka spruce and, althoughthere are many uncertainties requiring further research,this cladding market could be attractive to Scottishsawmills in the future.

Affordable Low-energy Houses in

Lindas, Goteborg, Sweden

Lindas lies approximately 20 km south of the city ofGoteborg in Sweden. Egnahemsbolaget, a city-ownedcompany, has constructed 20 affordable terrace houseswhich make use of high levels of insulation and heatexchangers. This innovative combination has replacedtraditional heating systems with a more sustainablealternative. The construction costs were in line withwhat conventional buildings would normally cost toassemble in Sweden. Additional expenditure on super-insulation and heat recovery is paid for by lowerheating and energy costs.

The houses are timber construction with traditionalwhite-washed timber facades. They provide theiroccupants with a high-quality living environment andmake few demands on their lifestyle. As there is no

A trussless structureallows greaterinterior space, andwall and roof panelswere prefabricated.The wall constructionis breathable with alightweight timbercladding.

Detailing of the eaves, showing timber use.

55

conventional heating, occupants must observe some“commonsense rules” to maximise the full benefit ofthe building. If it is cold then it is best not to open awindow and create a through draft; similarly, on hotdays, closing blinds and awnings on south-facingwindows is a way of controlling internal temperatures.

The layout of each home maximises the benefits ofpassive solar gain (heat and light obtained directly fromthe sun). Balconies and projecting eaves offer shadeand this helps to offset overheating in the summer. Asthe homes are terraced in blocks of six or four, the

area of external wall requiring super-insulation andtreatment for airtightness is much reduced. A windowplaced strategically in the middle of the house providesnatural light and a mechanism for effective ventilationduring warm sunny days.

Heating in the house is supplied by exhaust air via aheat exchanger. The remainder of the heating issupplied by heat generated by the occupants, electricalappliances, and lighting. Solar collectors provideenergy for half of the hot-water requirements.

Efficient insulation with passive solarheating is the key to energy savings inthese timber terraced houses in Lindas.

Estimated energy use in a normal year

Household electricity: 2900 kWh

Hot water: 1500 kWh (50% of 3000 kWh, the rest from solar collectors)

Electricity for services, fans, pumps: 1000 kWh

Total: 5400 kWh

Source: The Swedish Council for Environment, Agricultural Sciences

and Spatial Planning (FORMAS)


56 Building Green

The world is changing towards a greater understandingand acceptance of the need to incorporate sustainabledevelopment principles in all we do. With its impacton resource use, contamination of the environment,and production and disposal of waste, the buildingindustry is a prime candidate for adopting sustainabledevelopment practices. Governments are becomingaware of the need to address urban sustainability as awhole. The potential contribution of sustainablebuilding practices to that process and outcome willundoubtedly be recognised.

Businesses have increasingly recognised that there isnot just an ecological and moral imperative, but thatthere are also significant cost savings to be made. Therange and extent of policies relating to sustainablebuilding, set within a context of sustainabledevelopment strategies as a whole, and an increasingfocus on urban sustainability, are rapidly evolving.Experience in their application and tools for theirassessment are also growing, although still in theirinfancy.

We have looked at the sustainable characteristics oftimber and wood products and in this Bulletin we putforward the reasons why they are such ideal materialsto use in implementing a sustainable approach tobuilding and the built environment. There is potentialfor timber to be viewed as the preferred material forthe future. Organisations working in materials researchcite timber as generally having the properties andqualities which best match the sustainability criteriawhich are increasingly being used. This includes therole of timber production and wood manufacture inthe strengthening of local and regional economies. Forthese reasons, timber is a first choice for those wishingto incorporate sustainable solutions into their everydayplanning and design for the built environment.

More needs to be done to promote to New Zealandarchitects as well as builders, timber’s positiveenvironmental benefits and the role that timber canplay in a sustainable approach to building. Wood’s highsustainability rating, compared with other materials,when using embodied energy and life cycle analysis,is not well known or expressed. Examples ofchallenging design in timber seem to be lacking.Innovative architecture in New Zealand is more likelyto use materials such as steel and concrete. There is,therefore, a need to promote to designers and architectsthe wide variety of applications for wood in building.That is not to say that the sustainability of timber and

wood products cannot be improved. Much work is stillneeded. As the building industry becomes morefamiliar with the concepts of sustainable building andmore directed through international, national, and localregulation to implement them, timber has the potentialto become a favoured material. Some quarters arguethat timber will be THE material of the future.

The interest is there, and it is widely acknowledgedthat the market is changing, driven primarily byoverseas markets and conditions, and the New ZealandGovernment response to alignment with theseinternational strategies. World trends in sustainablebuilding policies and practices, as well as NewZealand’s own commitments to sustainabledevelopment and international agreements, such as theKyoto protocol and the national sustainabledevelopment strategy, are beginning to increase thepace. There is recognition that these trends areprofound and inevitable. From the architectural,building, and timber industry sectors, there appears tobe an agreement that this focus will sharpen withinthe next 2 to 4 years. A lead by the public sector,particularly central Government, is viewed as a keygoal.

Much work needs to be done to increase the builtenvironment sector’s understanding of the desirablequalities of and the range of uses that can be found fortimber and wood products. Changes in Governmentpolicy and current legislation will also be needed torealise timber’s full potential within a wider sustainabledevelopment framework. Architectural practices andbuilders operating in the sustainable development areawill find themselves more in demand and grow, andothers will recognise the need to follow, backed up bychanges in legislation.

Conclusions

Medium-density timber housing in a neighbourhood nearHolmenkollen, Oslo.

57

Appendices

Appendix 1: Enhancing the

Profile of Wood

Promotion of Wood

Both European and United States timber organisationsacknowledge that the industry generally has suffered fromnegative public perceptions and lack of understanding whichneeds to be addressed through positive marketing andgeneral education. The main issues for the public concernthe felling of older trees to produce timber and theenvironmental impacts of wood-processing industries. Stepsare being taken within the timber trade to improve this image,and to present the use of timber and timber products asmaking a valuable contribution to sustainable developmentin environmental and economic terms.

The Canadian Wood Council actively promotes the benefitsof using wood in sustainable construction. This organisationhas put out many brochures and publications, including factsheets and case studies, which show convincingly that woodis not only a renewable and sustainable material, but that itcan also be used to good effect in a multitude of differenttypes of building projects, from residential to schools, officeblocks, and four-storey condominiums. The Canadian WoodCouncil also provides technical bulletins, span tables, anddesign manuals for aiding practitioners in designing andworking with wood.

New Zealand

Although there is no single wood promotion entity in NewZealand, both the Timber Industries Federation and the PineManufacturers Association actively promote the use ofplantation pine in construction and non-structuralapplications. Additionally, the New Zealand ForestIndustries Council is instrumental in overcoming tradebarriers to allow the abundant sustainable plantation timbersfrom this country to be available in other markets,particularly markets such as China which, due to a ban ondomestic unsustainable timber production, now relies onsustainable wood imports for its construction needs.

Wood for Good

In the United Kingdom, the industry-based Wood for Goodpromotional campaign, launched in 2000, targets trade andconsumer audiences as well as senior politicians andexecutives and policy makers. Its 3-year campaign isworking to promote the characteristics of timber and woodproducts as leading the sustainable qualities amongst

building materials, including lobbying for governmentalsupport in this drive.

In particular, the campaign has been actively supportingresearch into life-cycle analysis/assessment of timbers fortheir subsequent promotion, and to provide a scientificargument for the environmental benefit of timber. The Woodfor Good campaign has done a lot to raise the image of woodin the public eye; however, there are still three areas whichare recognised as needing improvements in perception:

• Consumer recognition that use of wood could raise thevalue of their properties

• That wood is sustainable and a material for the future

• That modern wood (incorporating both design andimproved modifying technologies) does not rotprematurely.

Be Constructive!

The North American Wood Promotion Network (WPN) hasa promotional campaign called “Be Constructive” to educatethe public about the positive benefits of using wood forconstruction. The WPN successfully brought about acoalition of wood producers to combat the negativeperceptions amongst the public concerning the use of woodin building projects. Particular messages that have beenpromoted include:

• North American forests have grown in area by 20% in30 years, despite being used extensively forconstruction

• Timber is easy to work with, is natural, and is quick toerect.

Appendices

58 Building Green

Appendix 2: Obstacles to

the Sustainable Use of

Wood In Construction

Timber is an established part of Australasian building cultureand there is a general acceptance of wood as a buildingmaterial, especially in private building. However, Nolan(undated) proposed that:

“The technical rationalist training of many designprofessionals; the physical characteristics of timber;the traditional acceptance of timber; the structure ofthe timber industry; and the technical concentrationof the industry’s research effort; combine to form aframe of view that timber is an unreliable materialand that this restricts the use of timber in non-domesticapplications”.

Promoting timber as a key element in sustainabledevelopment needs to be balanced by its limitations. Timberhas a role in reducing energy use and emissions (seeBuchanan & Levine 1999 for the New Zealand situation),but other materials play an important part, particularly inreducing energy use in a dwelling, as distinct from the energyused in its construction.

Environmental Impacts of Wood as

a Building Material

Environmental impacts result from wood-drying processes,wood adhesives, and surface protection systems. Impactsassociated with timber treatment include leaching of creosotefrom treated poles, (creosote is no longer used in NewZealand), leachate from wood waste dumps and storageareas, and emissions from incineration of wood waste. Gluesused in wood composites have raised concerns around thelong-term slow emission of formaldehyde fumes and theirpotential health hazards. However, these emissions arereduced by covering or sealing particleboard flooring andpainting MDF surfaces (Todd & Higham 1996). Manytraditional interior decorating materials pose health andcomfort hazards to building occupants because they “off-gas” toxic or annoying fumes. The most common of theseare volatile organic compounds and formaldehyde. Thebuild-up of these fumes, along with carbon dioxide, mould,bacteria, fibres, and dust can lead to the “sick buildingsyndrome” common in modern office buildings.

Popular Misconceptions

Misconceptions or misunderstandings about the role whichwood can play in achieving a sustainable desirable dwellinginclude:

• Timber is an out-of-date material

• Timber-framed houses are non-durable (exacerbatedby architectural fashion and poor building practices).

To some degree these misconceptions have been aided bythe development of integrated, multi-storey, design and buildsystems that do not include timber.

Availability of Sustainably

Produced Timber

There have been many reports and campaigns surroundingthe world shortage of timber, and calls to limit the use ofwood in buildings and reuse wooden components, in orderto reduce the destruction of the world’s old-growth forests.Although there are examples of tropical and old-growthhardwood species being clearfelled, many of the world’sforests are sustainably managed, and avoidance of the useof wood per se does not solve the problem. Some areas ofthe world, particularly in the Southern Hemisphere, havean oversupply of timber for their needs, especially fromsustainably managed plantation species. Instead, a moreprudent approach to the use of wood is required, to ensurethat wood used comes from salvage or an area of sustainablymanaged timber.

Fire

The knowledge that wood burns can be a factor in timbernot being specified for industrial buildings. However,wooden structures are known to survive a fire very well,and in some cases perform better than steel structures. Solidwood chars at a rate of around 0.6 mm/minute, meaningthat, provided a fire is extinguished within a reasonableperiod, most of the larger beams will still be able to bear theload, and the structure will not collapse on top of theoccupants. Steel beams, however, may distort in high heat,and in severe cases soften to the extent of compromisingthe building’s structural integrity.

Decay

Although untreated radiata pine used in dry interiorapplications such as stairs, joinery, and wall panelling hasan indefinite life, radiata pine products used in externalapplications such as weatherboards or framing exposed toground atmosphere require preservative treatment to avoidbiodegradation. Recent examples of fungal attack in wallframing in leaking walls have heightened the perception oftimber’s vulnerability to moisture. Despite these recentexamples, timber has been used for centuries as a buildingproduct, and there are many Northern Hemisphere timber

59

buildings still in use after 400 years or more. The problemis not in the timber itself, but rather in the design choice ofspecies, preservative treatment, and grade appropriate forthe intended use. Through proper use of design, detailing,and preservation, timber can be used very successfully formany built environment applications.

Wood Quality

In recent years, there have been a number of reports ofbuilders’ dissatisfaction with the declining quality ofsoftwood structural timber. The main concerns appear to bedimensional instability, and lack of uniformity of the timber— in particular, stiffness uniformity between pieces ofsimilar grade. Adoption of quality-assured mechanical-grading systems will assist in maintaining a market for solidstructural radiata pine products. In the meantime there is anincreasing use of engineered structural products such aslaminated veneer lumber and fingerjointed products.

Building Industry

There are issues with what is seen as New Zealand’s smallmarket, and difficulties in breaking through the limitationsof supply caused by exclusive contracts operating with afew large building supply companies. This is viewed ashindering the development of new products and diversityof supply. There are also concerns about the “unmodernised”state of the building industry as a whole. “Deskilling” aswell as lack of innovation in building designs are hinderinggrowth in the application of sustainable building principles.The current state of industry expertise is insufficient toprovide the construction details needed to ensureweathertightness in all of today’s monolithic, clad, eavelessbuildings. With so many tasks on site contracted out tovarious companies, problems arise from the lack of overallco-ordination. Nobody is looking at “the gaps in-between.”

Timber Industry

Despite New Zealand’s abundant timber supply, it is limitedby its lack of variety, particularly in hardwoods and, from asustainability point of view, the existing plantation practicesand timber treatments are not without their critics. There isalso concern about the quality of structural timber sold inNew Zealand. Several factors are involved, includingharvesting age and grading systems.

The forestry industry in New Zealand is acutely aware ofthe environmental issues, and will be looking to assess andaudit the environmental performance of both the processingand supply chains once there is agreement on a New Zealandcertification standard for forestry management. Ideally, NewZealand’s forestry industry has the potential to exploit this

situation and offer fully audited, sustainably produced, rawand manufactured timber products to a world whichincreasingly accepts the role of trees and timber forsustainable development.

Investigation into naturally durable timber species is alsoneeded to counter the difficulties surrounding timbertreatments. Taking advantage of the different characteristicsof a range of alternative plantation species allows greaterdiversity of uses as well as diversity in land management.

Whilst alternative plantation species are being advocated,existing and potential users face a range of problems. It iswell known that stocks of macrocarpa, Lawson cypress, andeven various eucalypts are in short supply, and often are notthe best of quality due to poor forest management. This limitsdevelopments which specify these alternative timbers. Lotsof farm grade macrocarpa is available, but it is often notsuitable for framing. Good quality can be found but, as onebuilder put it, those who are alternative have to be “moreorganised and knowledgeable” in order to get what theywant. They also have to contend with a lack of informationin timber yards about where the timber comes from, andwith the unreliability of information given by timbermerchants, who have been compared with car salesmen inthat “they’ll tell you what you want to hear”. If there wasmore demand at the moment, suppliers would not be able tocope. Fifteen years down the track the market could bedifferent, with good prices being paid for such crops.

Generally there is not enough experience in producing,processing, and working with some of these alternativeplantation timbers, and not enough research has been doneor disseminated to help those who want to learn. The FarmForestry Association is researching the best management ofvarious species and their workability, which includesinvestigating the characteristics of various species ofEuropean trees grown in New Zealand conditions. Once thisis done, it is suggested that the Government could help fundthe planting and promotion of the best varieties, as it didwhen radiata pine first came on the scene.

Appendices

60 Building Green

Appendix 3: Life-cycle

Assessment Systems

BREEAM

The United Kingdom’s Building Research Establishment’sEnvironmental Assessment Method (BREEAM), used since1990, is regarded as the most established assessment methodto guide the minimisation of environmental effects ofbuildings. BRE have continued to set the pace with new“environmental profiles” along with a computer softwarepackage “Envest” which allows designers to consider thelife-cycle impact of building materials at the buildinginception stage (BRE 2000). Launched in 1990, BREEAMhas been accepted in the UK construction and propertysectors as offering best practice in environmental design andmanagement.

BREEAM is a tool that allows the owners, users, anddesigners of buildings to review and improve environmentalperformance throughout the life of a building. It sets abenchmark for environmental performance and provides awide range of benefits. Some 400 major office buildingshave been assessed and there are schemes for industrial units,supermarkets, and homes. The homes version of BREEAMis called EcoHomes. It provides a rating for new andconverted or renovated homes, and covers houses,apartments, and sheltered accommodation.

LEED

The US Green Building Council has developed its ownmarket-driven building rating system, looking atenvironmental performance over a building’s life-cycle.Leadership in Energy and Environmental Design (LEED)gives credits for adherence to qualities and processes usingsustainable building principles. The City of Portland,Washington, has developed its own version to rate buildingsconforming to its own sustainable building policies. Toolsfor assessing environmental performance have beendeveloped by the National Institute of Standards andTechnology, supported by the Environmental ProtectionAgency (EPA), based on the ISO 14000 standards. Their“Building for Environmental and Economic Sustainability”(BEES) software measures all stages in the life of a buildingproduct.

Ecospecifier

In Australia, the Australian EcoSpecifier project developedby the Royal Melbourne Institute of Technology University’sCentre for Design has produced life-cycle information andspecifications of ecomaterials, including some informationabout trends amongst major suppliers in this area (RMITCD2000). Reconstituted timber, some plantation timber(macrocarpa), radially sawn timber, and FSC-sourced timber

are cited as qualifying as an Environmentally PreferableMaterial (or EcoMaterial). Further work is being carriedout with Government sponsorship to assess the status oflife-cycle assessment (LCA) tools in the building andconstruction sector and to develop strategies to improve theuptake and use of these tools within Australia (RMITCD2000).

Ecoscan

Another software product, Ecoscan 3.0, is a Windows-basedprogram originating in Holland but available in English andother European languages. It uses material databases toevaluate the environmental impact, LCA, and LCC (life-cycle costings) of any products, not just buildings. A numberof other such tools may be found by searching the Web.

ATHENA

The Athena Sustainable Materials Institute has developed acomprehensive LCA decision-support tool which provideshigh-quality environmental data, and the evaluations assistdecision making for informed environmental choices.Common building materials from cradle to grave areassessed for the environmental effects at each stage in theproduct’s life-cycle. ATHENA v2.0 collates these data in abuilding systems context and evaluates conceptual designsfor the full environmental story

Assessment Systems

American Society for Testing and Materials (ASTM) http://www.astm.org — sustainability standards of buildingmaterials

International Organisation for Standardisation http://www.iso.ch / ISO 14000 series

Building Research Establishment (BRE) http://www.bre.co.uk/sustainable/index.html for standards andassessment systems BREEAM, Environmental Profiles andmore

Centre for Design at RMIT, http://www.cfd.rmit.edu.auecospecier project

National Institute of Standards and Technology http://www.bfrl.nist.gov/oae/oae.html

US Green Building Council http://www.usgbc.org forLEED system

61

Appendix 4: Sustainable

Forestry and the

Environment

Trees use sunlight, air, water, and soil nutrients to producematerial for fibre and fuel. Wood is 100% renewable andtrees form an important part of our ecosystem. In this section,we summarise the roles that New Zealand forestry plays inproviding wood, economic and regional development,recreational use, and biofuels, and in sustaining forest andwildlife ecosystems.

New Zealand’s Plantation Forests

Plantation forestry in New Zealand began at the turn of thelast century in response to a foreseen depletion of our slow-growing native forests which were being consumedunsustainably. Radiata pine was introduced to New Zealandin the late 1800s and extensive plantings commenced in theearly 1920s. Since that time, research into breeding andsilviculture has enabled radiata pine forests to be managedfor timber over short rotations of 25 to 30 years. Other exoticspecies planted for wood production include Douglas fir,cypresses, eucalypts, and Australian blackwood.

Plantation forests in New Zealand now cover about 1.8million hectares, or about 7% of the total land area, andsupply far more than the domestic market requires.

Regional Development

Today, forestry contributes over NZ$2.5 billion in exportearnings to the New Zealand economy and employsapproximately 24 000 people directly and in first-stageprocessing (MAF 2002). However, New Zealand’splantations have a much wider role to play in ourcommunities than employment and wealth creation. Theinternational response to Kyoto, in using trees as a carbonsink, will enhance the value of our already plentiful forestplantations. Many plantations are well located to meet therecreational needs of local communities for a wide range ofactivities including tramping and cycling, or just as a placefor relaxation. The Whakarewarewa Forest in Rotoruareceives over 100 000 visits per annum, and similar figuresapply elsewhere — for example, at Bottle Lake Forest Parknear Christchurch.

Plantation forests have an important role to play inconserving soils. The East Coast Forestry Project is seekingto protect the worst 60 000 ha of severely eroding land inthe Gisborne District.

The wildlife value of many plantation forests is gainingrecognition. Many species of indigenous plants, fungi,insects, and birds have successfully colonised exotic forests.Plantation forests generally provide a habitat for more native

species than an equivalent area of pastoral grassland. Someplantation forests have potential to meet specificconservation objectives (Brockerhoff et al. 2002).

Supply

New Zealand is a net exporter of wood products from itsplantation softwood forests. The harvest is expected to reach30 million m3 by 2006, providing opportunities for newemployment and processing, as well as value-added exportopportunities. While radiata pine continues to be the majorplantation species, other species are also planted for theirpotential on specific sites and for particular end-uses.Douglas fir, Australian blackwood, cypresses, and eucalyptsare already planted extensively, and Douglas fir andeucalypts are harvested in significant quantities.

Though there is a reasonable demand for timbers for high-value end-uses in New Zealand, supply of both special-purpose exotic species (non radiata pine and Douglas fir)and native home-grown timbers is limited. Exotic timbershave therefore been imported, both in solid and veneeredform, for these specialist product needs. However, withgreater emphasis on sustainable forest management practicesand forest certification, issues regarding the use of illegallogging practices and the unsustainable long-term harvestingof old-growth timber have seen many imported timbers,especially tropical species, come under close scrutiny.

However, timber from these new plantations will not beready for harvest in the short-term. In 2001, New Zealandproduced 28 000 m3 of native sawn timber, one-third of theamount produced a decade ago, and just 24 000 m3 of exoticminor species (non radiata pine and Douglas fir).Consequently, furniture and joinery manufacturers are nowsupplementing their timber needs through imports and byusing recycled and demolition timbers. The value of sawntimber products imported into New Zealand over the past5 years has increased by 28% as domestic demand for non-radiata pine timbers cannot currently be met, sustainably,from our native timber resources or other exotic plantations.

Forest Certification

The way wood is produced in New Zealand is critical to ourability to deliver long-term sustainability objectives. NewZealand is an active participant in the Montreal Process —an agreement between primarily Pacific Rim states with astake in ensuring that their forest resources are managed ina sustainable way. As a guarantee of environmentalperformance, many companies have also sought some formof forest certification which demonstrates that their forestmanagement operations do not cause irrevocable harm toour land, air, water, and wildlife, and respect communityinterests and cultural heritage.

The most frequently adopted certification scheme in NewZealand is operated under the auspices of the Forest

Appendices

62 Building Green

landscaping applications. Unlike many competing products,it produces safe reliable products that can be recycled ordisposed of with low environmental impacts.

Renewable Energy from Biofuels

Bioenergy is a form of clean, green, renewable energyharnessed from conversion of biomass into energy. Biomassis widely available in New Zealand in the form of woodresidues, agricultural wastes, or energy crops. Bioenergy,as practised in New Zealand, does not result in deforestationor global warming. Energy derived from wood-processingresidues provides around 6% of New Zealand’s consumerenergy (29 PJ out of a total of 453 PJ).

Currently, the biggest user of bioenergy in New Zealand isthe forest industry, mainly for timber drying and processingheat at pulp and paper mills or panel manufacturing plants.The forestry sector uses biomass for 50% of its processingrequirements through waste-to-energy schemes, burningblack liquor from paper manufacture and other residues inboilers for process heat and electricity for internalconsumption and for export to the grid.

Domestic households, use firewood for space- and water-heating, where it often has a competitive advantage overfossil fuels in providing low temperature heat.

Stewardship Council. Under this scheme, forest managersmust demonstrate that processes are in place to ensure thatpotential ecological, environmental, economic, social, andcultural impacts are addressed. Approximately a third (500000 ha) of New Zealand’s plantation resource is managedunder an approved Forest Stewardship Council regime and,to ensure that timber produced from certified forests isclearly identified in the market place, some companies havesought Forest Stewardship Council Chain of Custodyaccreditation. This ensures that timber produced under anaccredited Forest Stewardship Council regime is clearlyidentified through all stages of processing.

Future Forests

Currently there is a limited range of New Zealand-grownspecies for designers and architects to exploit for innovativeand sustainable building. Although radiata pine has manyqualities as a construction timber, there is interest indeveloping alternative species timber for structural andhigher value end-use application. The profitability of short-rotation radiata pine forestry has in the past made this speciesparticularly attractive to forest investors. Alternative species,with longer rotations, are less attractive as commercial forestinvestments. However, short-rotation eucalypt forests arebeing planted. New wood-processing techniques such aslaminated veneer plants and efficient fingerjointing systemscan influence the profitability and management strategiesof radiata pine and other species.

The future face of forestry in New Zealand will increasinglyinvolve small forest growers and Maori landowners andorganisations. Forestry faces an exciting and dynamic future,capitalising on the energy of regions and their communities.

Wood has many advantages over competing materials whenused for constructing and fitting out buildings, and for

Annual new planting estimates by major species 1995–99*Sources: MAF National Exotic Forest Description 2000; National Nursery Survey 1998* The 1999 figures are based on the national nursery survey and have not been adjusted for the NEFD results.

63

Appendix 5: Weblinks

New Zealand

Architectus www.architectus.co.nz

Building Research of Aotearoa New Zealand (BRANZ)www.branz.org.nz

Christchurch City Council www.ccc.govt.nz

Cooperative Housing Assocation of Aotearoa NZ(CHAANZ) www.converge.org.nz/chaanz/index.html

Energy Efficiency and Conservation Authoritywww.eeca.govt.nz

Hamilton City Council www.hcc.govt.nz

Housing New Zealand Corporation www.hnzc.co.nz

New Zealand Building Industry Authoritywww.bia.govt.nz

New Zealand Business Council for SustainableDevelopment www.nzbcsd.org.nz

New Zealand Institute of Architects www.nzia.co.nz

Pine Manufacturers Association www.nzpra.org.nz

Waitakere City Council,NZ

Better Building Code and Sustainable DesignGuidelines www.waitakere.govt.nz/AbtCit/ec/bldsus/index.asp

New Lynn Community Centre, Waitakere City Councilwww.waitakere.govt.nz/AbtCit/ec/ecoinit/nwlyncc.asp

Australia

Centre for Design at RMIT http://www.cfd.rmit.edu.au

Commonwealth Scientific and Industrial ResearchOrganization — Division of Building, Construction &Engineering (CSIRO) http://www.dbce.csiro.au

Forest and Wood Products Research and DevelopmentCorporation http://www.fwprdc.org.au

Housing Industry Association’s Green Smart housingprogramme http://www.greensmart.com.au

New South Wales Department of Public WorksEnvironmental Performance Guide for Buildingshttp://asset.gov.com.au/environmentguide

Olympic Exhibition Building, Sydney, Australiahttp://oak.arch.utas.edu.au/projects/aus/329/Default.html

Timber Research Unit, School of Architecture, Universityof Tasmania http://oak.arch.utas.edu.au/tru

UK

ARCA the Journal of Scottish [email protected]

Association for Environment Conscious Buildinghttp://www.aecb.net

Bristol City Council Timber policyhttp://www.bristol-city.gov.uk

Building Research Establishment (BRE)http://www.bre.co.uk/sustainable/index.html

Department of Trade and Industry, SustainableConstruction http://www.dti.gov.uk/construction/sustain

South Somerset District Council, UK

South Somerset District council’s sustainableconstruction website http://www.southsomerset.gov.uk/general/sustain/index.htm

Somerset Sustainable Housing websitehttp://www.sustainablehousing.org.uk

Sustainable Homes (Housing Association good practicesite) UK http://www.sustainablehomes.co.uk

Timber Trade Federation http://www.ttf.co.uk

Well Built — Local Authority Sustainable Constructionnetwork (UK) http://www.wellbuilt.org.uk

wood for good campaignhttp://www.woodforgood.com/utility/about/index.htm

USA

American Institute of Architects — Committee of theEnvironment — (Mainstreaming Green: SustainableDesign for Buildings and Communities)http://www.e-architect.com/pia/cote/home.asp

Building Environmental Science and Technology (BEST)Green Building Primerhttp://www. energybuilder.com/greenbld.htm

City of Portland, Oregon, Office of SustainableDevelopment http://www.sustainableportland.org/

City of Seattle’s sustainable building web pagehttp:// www.ci.seattle.wa.us/light/conserve/sustainability

DoE Centre of Excellence for Sustainable Developmenthttp://www.sustainable.doe.gov/buildings/gbintro.shtml

Environmental Building Newshttp://www.buildinggreen.com / web links to sustainablebuilding sites

Appendices

64 Building Green

Partnership for Advancing Technology on Housing(PATH) www.pathnet.org

State of California Green Building Design andConstruction web pageshttp://www.ciwmb.ca.gov/GreenBuilding

Sustainable Building Industry Councilhttp://www.sbicouncil.org

US Green Building Council http://www.usgbc.org

Wood Promotion Networkwww.woodpromotion.net and www.beconstructive.com

Canada

Athena Sustainable Materials Institutehttp://www.athenasmi.ca/

Canadian Wood Council WoodWorkshttp://www.wood-works.org/general_info

Green Building Information Councilhttp://greenbuilding.ca

Green on the Grand, Canada http://www.advancedbuildings. org/_frames/fr_cs_gog.htm

Sustainable Building Canadahttp://www.sustainable buildingcanada.org(under construction)

Other International

CIB – International Council for Research and Innovationin Building and Construction http://www.cibworld.nl

European Green Building Forum www.egbf.org

European Sustainable Cities and Towns Campaignhttp://www.sustainable-cities.org

Forest Stewardship Council http://www.fscoax.org

Ministerial Conference on the Protection of Forests inEurope http://www.minconf-forests.net/

OECD sustainable construction web sitehttp://www.oecd.org/env/efficiency/construct.htm

The International Council for Local EnvironmentalInitiatives World Secretariat (works with localauthorities) http://www.iclei.org

The International Initiative for a Sustainable BuiltEnvironment http://www.iisbe.org/

UN/ECE Timber Sectionhttp://www.unece.org/trade/timber

Union of International Architectshttp://www.uia-architectes.org/count-uia.shtml

United Nations Centre for Human Settlementshttp://www.unchs.org

United Nations Commission on Sustainable Developmenthttp://www.un.org/esa/sustdev/index. html

World Business Council for Sustainable Developmentforest industry project http://www.wbcsd.ch/projects/sectoral/forestry/overview.htm

65

References

Aitoaho, Heikki; ViKaarlo 1998: Wood in architecture. PUU- Finnish Wooden Architecture and Construction 3.

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67

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References

68 Building Green

Glossary

ACQ a copper plus quaternary ammonium compound system that provides the same level ofprotection to wood as CCA preservatives.

Aotearoa “The land of the long white cloud” — a Maori name for New Zealand

Australian blackwood Acacia melanoxylon

BRANZ Building Research Association of New Zealand

CCA copper chrome arsenate

CIB International council for Research and Innovation in Building and Construction

Cladding exterior lining on the walls of buildings

CO2 carbon dioxide

Cypress in New Zealand, the three main species are Cupressus macrocapa (Macrocarpa), Cupressuslusitanica (Lusitanica/ Mexican cypress), and Chamaecyparis lawsoniana (Lawson’s cypress)

EECA Energy Efficiency and Conservation Authority

GHG greenhouse gases

Global warming the temperature rise attributed to emissions of GHG

Glue-laminated/glulam wooden structural members formed by laminating wooden pieces together using structuraladhesive

GWP global warming potential

HVAC heating, ventilation, and air conditioning.

Kyoto Protocol agreement to implement national measures to limit greenhouse gas emissions

LOSP light organic solvent preservative

MAF Ministry of Agriculture and Forestry

Mm 3 million cubic metres

MDF medium density fibreboard

NOx nitrous oxide

NZS 3604: 1999 New Zealand Standard 3604: 1999

OECD Organisation for Economic Co-operation and Development

PCE Parliamentary Commissioner for the Environment

PJ petajoules

RMIT Royal Melbourne Institute of Technology

SmartGrowth a principle of planned urban development for more liveable communities, which arose in theUnited States in the 1990s.

SOx sulphur oxides

stud vertical wall framing member

taonga treasure

TBTN tributyltin napthenate

TBTO tributyltin oxide

UN United Nations

UK United Kingdom

whares houses

MfE Ministry for the Environment

WBCSD World Business Council for Sustainable Development