community live build project

WORKSHOP REPORT

A workshop to explore the qualities of rammed earth and bamboo in Scotland.

Building with Rammed Earth and Bamboo in Scotland

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A GUIDE FOR POLICY MAKERSAND DESIGNERS OF THE FUTURE

Building with Rammed Earth and Bamboo in Scotland

by

Nicholas Goward&

Lindsay McDonald

Publication

Presented to the Department of Architecture at theUniversity of Strathclyde

in Partial Fulfillment for the requirements of the

Master of Science in Advanced Architectural Studies

The University of Strathclyde August 2014

Acknowledgements

The authors would like to thank:

Jackie and Raymond from the At Home Centre Airdrie for their support throughout the project and for allowing us to use their site

The staff and students of the Activity Agreement Programme from both the Motherwell and Airdrie Education and Youth Centres for their help with the project

GAP Group Hire Solutions for the supply of machinery free of charge

Positive Land Solutions for supplying the paving slabs free of charge

Tillicoultry quarries for the supply of the quarry fines free of charge

UK Bamboo Supplies Ltd. for the discount given on the purchase of the bamboo poles

Glasgow Wood Recycling for the discount on the purchase of scaffolding boards

Building with Ramed Earth and Bamboo in Scotland

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ABSTRACTBUILDING WITH BAMBOO AND RAMMED EARTH IN SCOTLANDA GUIDE FOR POLICY MAKERS AND DESIGNERS OF THE FUTURE

Our Masters project is heavily influenced by the time spent in Ecuador during our research trip for Post Graduate Diploma. Whilst in Ecuador we visited the three regions of hugely differing land-scapes and cultures: Costa, Sierra and Oriente. Al-though vastly differing in many ways the construc-tion methods of using earth and bamboo was the thread that connected these regions together. A seemless materiality that transcends the social, political, economic and environmental barriers, and in particular the lasting effects of oil contami-nation that mar this beautiful country.

This experience led us exploring the possibility of using these beautiful and versatile materials in Scotland. Having researched the materials exten-sively we discovered that bamboo can be grown in a temperate climate and that many local quarries have the clay rich soil that is required for rammed earth building.

Our experiment was developed through a series of workshops in collaboration with the Airdrie Learning Centre and a group of young adults from their 16+ Activity Agreement Programme. We began the design workshop with an introduc-tion to the materials, letting the students feel and use them in small and medium scale experiments. This led to the introduction of a design competi-

tion in which the students made models of their ideas and presented them to the group. The out-come of which, allowed us to develop a brief and design which would form the basis of the 1:1 build workshop that we built the following week.

The 1.1 build workshop lasted seven days and was a collaborative effort between the students, the staff and ourselves. Despite the challenges faced everyone contributed to the final outcome, with everyone learning a great deal along the way. The young people involved also gained the following qualifications as a result of the project-

• Team work (intermediate 1)• Working with others and problem solving (SQA)• Youth Achievement Award• The Saltire Award for volunteering• The John Muir Award for awareness and responsibility for the natural environment

Overall this workshop report aims to illustrate the benefits and possibilities of building with rammed earth and bamboo as a cheap and sustainable building material for Scotland. With the additional benefit being to the future education of Scotland’s young people creating awareness to environmen-tal building methods and skill development.


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CONTENTS

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01 Introduction1.0 Who 1.1 What 1.1.1 Rammed Earth 1.1.2 Moso Bamboo1.3 Why 1.3.1 Advantages of Rammed Earth 1.3.2 Disadvantages of Rammed Earth 1.3.3 Advantages of Moso Bamboo 1.3.4 Disadvantages of Moso Bamboo1.4 Ecuador - Rammed Earth and Bamboo

02 History2.1 History of Rammed Earth Construction2.2 History of Bamboo Construction2.3 Lifecycle of Bamboo2.4 Timeline

03 Modern Develop3.1 Bamboo3.2 Rammed Earth

04 Structural4.1 Rammed Earth4.2 Bamboo

05 Pre- Workshop5.1 Soil tests5.2 Building Formwork

06 Design Workshop6.1 Description6.2 Photographs6.3 Final Presentations6.4 Scale Drawings

07 Build Workshop7.1 Day 17.2 Day 27.3 Day 37.4 Day 47.5 Day 57.6 Day 67.7 Day 7

08 Conclusion8.1 Opening Ceremony8.2 Learning Outcomes


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ABOUT1.0 WHO WE ARE

We are two students from the University of Strath-clyde, Glasgow studying for a Masters of Science in Advanced Architectural Design. We both com-pleted our Part II qualification and gained our Pg. Diploma in 2014.

Our Pg. Diploma’s was based on ‘Oil Exploitation’ in Ecuador for which we undertook a 3 month re-search period and then a 7 month design period to created interventions to help solve the problem of oil exploitation. During this period we visited Ecua-dor as part of our research to learn about the coun-try, culture, people and the devastating effects of oil in each of the three regions in the country.

During this research trip we came across the use of rammed earth and bamboo in the construction industry which led Nicholas to use both materials exlusively in the final design of his three interven-tions. Whilst in Ecuador visited the bamboo factory set up by the Univeristy of Guayaquil to expolore the structural properties; which only further en-hanced our fascination with this great material.

After returing from Ecuador both we kept up our in-terest in rammed earth and bamboo reading many books and online journals whilst also staying in con-tact with some of the students and professors we met in Ecuador.


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Rammed earth is a form of construction using com-pacted unbaked soil to create load bearing walls (Walker et al, 2009), sometimes with the addition of a binding agent; such as cement, clay, manure or lime. This ancient construction technique can also be used for foundations, floors, furniture and roof structures (Walker et al, 2009). The ideal soil is com-posed of around 70% sand and gravel and 30% clay (Easton, 1996), this is mixed with a little water to create a loose moist soil mixture which is then com-pacted within temporary shuttering[fig 1]. (Walker et al, 2009). Once one layer of soil is compacted more mixture is added into the formwork and the process is repeated, this gives the rammed earth structure its distinctive stratified aesthetic [fig 2].

Soils low in sand and high in clay need to have sand added or the walls can shrink and crack (Easton, 1996). Conversely, a soil mix low in clay and high in sand will have to have a stabiliser added to create a strong durable wall. The use of cement as a sta-biliser is an issue of debate as it increases carbon emissions by 10%; however some of this can be substituted with hydrated lime (Thomson, 2012). It is the aesthetic qualities, environmental prop-erties (such as climate regulation and low carbon footprint) and low cost that mak rammed earth a popular construction choice around the world.

1.1 IS RAMMED EARTH

Figure 1 - Rammed earth formwork Figure 2 - distinctive layers New Southeast Wyoming Welcome Center

WHAT?


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Bamboo is a member of the Poaceae grass fam-ily [fig 3]., of which there are 1400 varieties found worldwide (bamboo botanicals.ca). This wood like grass is the fastest growing plant in the world, with some species growing up to 8cm per day; it is also one of the hardiest plants, with an ability to be cul-tivated in almost every climate (although tropical conditions produce the most durable varie-ties) (moso-bamboo.com).

The bamboos of this group grow in temperate zones and have the characteristic of forming nodes in zigzag or other irregular forms. Moso bamboo is originally from China, nevertheless many species were cultivated in Japan, the America’s and Europe.

Moso Bamboo can also reach its maximum height and be ready for harvesting within 12 weeks[fig 4]. Other timbers used in construction take years to grow to full height; for example beech which takes 40 years and oak which takes 80 years [fig 5].(moso-bamboo.com). Construction bamboo has a higher compressive strength than wood, brick or concrete and a tensile strength that rivals steel making it a formidable building material.

Phyllostachys Pubescens (Moso)Height: 21mDiameter: 17cmOrigin: China, Japan and the United States

1.2 IS BAMBOO

Figure 4 - Moso Bamboo Forest Figure 5 - Moso Bamboo Harvest

WHAT?


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1.3 USE THESE MATERIALS

The purpose of this study is to showcase the qual-ities of rammed earth and bamboo construction in Scotland. We believe these materials could and should be more utilised in Scottish construction and throughout this publication our argument for this will be shown.

Rammed earth and bamboo are fantastic materi-als that are being readily used around the world and even in parts of Europe but Scotland seems oblivious to their obvious qualities. Rammed earth is the oldest building material, not only in Scotland but the world but somehow this mate-rial has been cast aside with other materials with higher CO2 emissions are being used instead.We aim to show the Scottish Government that these materials should be used in Scottish con-struction.

Soils low in sand and high in clay need to have sand added or the walls can shrink and crack (Eas-ton, 1996). Conversely, a soil mix low in clay and high in sand will have to have a stabiliser added to create a strong durable wall.

The use of cement as a stabiliser is an issue of debate as it increases carbon emissions by 10%; however some of this can be substituted with hy-drated lime (Thomson, 2012). It is the aesthetic qualities, environmental properties (such as cli-mate regulation and low carbon footprint) and low cost that mak rammed earth a popular con-struction choice around the world.

WHY?


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Figure 6 - (opposite page) Photograph of rammed earth and bam-boo

Figure 7 - (above) Photo-graph of students build-ing rammed earth and bamboo school by Ana Heringer

Figure 8 - (left) Photo-graph of rammed earth wall with bamboo roof truss


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1.3.1 RAMMED EARTH

ADVANTAGES

One of the main reasons rammed earth is be-coming more popular in recent years due to ris-ing ecological concerns (Easton, 1996). Rammed earth has far lower embodied energy in com-parison to traditional masonry or steel construc-tion (Walker et al, 2009). Additionally, the raw materials used (the soil) is typically taken from the site itself, and so transportation of materials becomes minimal [fig 6]. If a suitable soil is not found on the soil or a large enough quantity is unavailable then a good alternative is to ask for “Quarry fines” from a local quarry, which is far cheaper than trying to mix washed graded sands and clays from a supplier(Easton, 1996).

A major benefit is its ability to regulate temper-ature due the thermal mass and breathability of the walls (rammedearthconstructions.com). Heat is stored within the wall from the sun dur-ing the day when hot and is slowly released into the home as the cold night draws in. The thick-ness of the finished walls also acts as a fantastic noise insulation and act as fire protection (ram-medearthconstructions.com).

The versatility of rammed earth is also a major benefit. Walls can be created in flowing curved shapes or arranged in a linear fashion [fig7] . The finish can be smooth or rustic; the colour can be adjusted for personal taste; and the layers can be distinct to give a stratified effect or uniform for continuous colour (Walker et al, 2009).

Figure 6 - New Mexico desert by Signer Harris

Figure 7 - The Kendle Designs residence


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1.3.2 BAMBOOOne of the main advantages of bamboo is that it is a renewable material capable of rapid growth that can avoid deforestation (Minke, 2012). It is also easy to handle, cut and maintain by relatively unskilled labourers and with minimal equipment. Other advantages include:

• Due to its circular form and hollow sections bamboo is a light building material making it easy to transport and use on site.

• The external layer of the shell offers very high resistance to tension, equalling that of steel.

• Bamboo does not have bark, which, as with trees must be peeled.

• The branches are easy to remove

• Bamboo sequesters CO2

• According to regulations ISO 22156, 78.3 tonnes per hectare of bamboo are produced each year in the Coffee Triangle of Colombia, as compared with only 17.5 tonnes per hectare of wood. As a result, the yield of bamboo is 3.3 times that of wood (Minke, 2012)

Figure 12 - German-Chinese House, EXPO 2010, Shanghai, China


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1.3.3 RAMMED EARTH

DISADVANTAGES

• Susceptible to rot in damp conditions if untreated

• Very labour intensive

• Can be affected by insect infestation

• Foundations must be sized correctly

• May need reinforcement

• Formwork can be expensive

• Takes up to 2 years to dry fully

• Low thermal resistance

Figure 6 - New Mexico desert by Signer Harris

Figure 7 - The Kendle Designs residence

In damp and wet conditions such as the temper-ate climate of the UK- the durability and struc-tural properties of rammed earth can be com-promised if left untreated [fig10] (Walker et al, 2009). This problem can be mitigated by creating foundations with good drainage and by placing wall on a concrete footing to elevate away from the ground (greenhomebuilding.com). Addition-ally, a stabilised rammed earth wall (by using concrete or lime etc) will weather better in damp conditions but can be protected further with a cladding (Easton, 1996). Water resistant sealants are not recommended for rammed earth build-ings (Walker et al, 2009). Other disadvantages include.


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Bamboo does have some drawbacks though, Once dried bamboo like wood becomes flammable and so without a proper resistance coating can be very dangerous. Other disadvantages include:

• Its structural behaviour can vary greatly, de-pending on the species, the growing site, its age, the moisture content and the part of the stalk that is used.

• Bamboo is vulnerable to exposure to ultravio-let rays and rain, accordingly it requires protec-tion during the handling, execution and main-tenance of the project.

• Bamboo is sensitive to attack from insects and fungus. It must be impregnated or treated against them.

1.3.4 BAMBOO• Its round section and its tendency to crack

easily complicates the execution of joints and supports.

• Its conical profile changes the diameter and the thickness of the bamboo stem along its length.

• Rarely does the stem grow totally straight.

• The dulling of work tools is higher than with wood

• The strucutural calculations and construction permits are difficult to obtain since official regulations do not exist.

Figure 13 - Insects eating bamboo cane


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1.4 Rammed earth and bambooECUADOR

In March 2014 we were given the oppertunity to visit Ecuador to gather further information for our thesis.

Our Masters project is heavily influenced by the time spent in Ecuador during our research trip for. Whilst in Ecuador we visited the three regions of hugely differing landscapes and cul-tures: Costa, Sierra and Oriente. Although vastly differing in many ways the construction methods of using earth and bamboo was the thread that connected these regions together. A seemless materiality that transcends the social, political, economic and environmental barriers, and in particular the lasting effects of oil contamination that mar this beautiful country.

The Sierra region had many diffrent variations of earth building, due to its natural characteristics to resist effect from seismic activity. Addition-ally we saw examples in the Costa and Oriente regions where using earth to build was a cost effective alternative to concrete blocks.

The Coast town of Esmeraldas had many bam-boo structure due to its natural abundance. In Guayuquil we had the oppertunity to visit a Bamboo factory where prototype bamboo products (for fireprotection, cladding and roof-ing) were being tested. Here the versatility of the material became clear, with many diffrent characteristics being enhanced, and aesthetic qualities being developed through diffrent treat-ments.


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2.1 RAMMED EARTH

HISTORY

Rammed earth walls are found throughout the world sometimes centuries old, with many examples throughout Asia, Africa, Latin America and Europe. Evidence of the early use of rammed earth has been seen in Neolithic archaeological sites of the Yangshao and Longshan cultures along the Yellow River in China, dating back to 5000 BCE. By 2000 BCE, rammed-earth architectural techniques were commonly used for walls and foundations in China.

Rammed earth was probably introduced to Brit-ain by the Romans and so has been used in the UK for around 2000 years. However the most significant period of its construction followed its reintroduction into the UK in the early nine-teenth century, following a revival of interest in France. Throughout the ninteenth century a number of rammed earth buildings were erect-ed in south England.

After the first world war a small number of exper-imental houses were constructed in Amesbury, Wiltshire, many of which are still in use today. Interest in rammed earth fell after World War II when the costs of modern building materials dropped. Rammed earth was considered sub-standard, and still meets opposition from many contractors, engineers, and tradesmen who are unfamiliar with earth construction techniques.

In recent years a number of rammed earth pro-jects have been completed in the UK. Applica-tions to date include the Eden project visitor centre and Centre for Alternative Technology’s AtEIC Building. The stimulus for this develop-ment has primarily been the desire to reduce the environmental impact of building and to explore more sustainable and natural building methods. The aesthetic qualities of rammed earth has also been a factor.

Figure 15 - Ruins of Chinese watchtower made of rammed earth (202 BC - 220 AD)


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Figure 9 - Part of the Great Wall of China in the Gansu Province built from rammed earth

Figure 8 - Five story rammed earth building which is over 1000 years old

Figure 9 - Example of middle eastern rammed earth housing

Figure 8 - Giza Pyramids built from rammed earth


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26Figure 10 - Oldest bamboo structure in the world dating back to 960 AD the Qian-Xian bridge

Bamboo currently grows throughout the world, but the origin of bamboo is believed to be ancient China. Bamboo was first found and used in China more than 5000 years ago, which is why the woody plant conjures up images of pandas eating shoots and leaves in the Orient. Even though its many uses are only just becoming widely known, the bamboo plant as an alternative material began long before “going green” became a trend.

The species of bamboo that we know today evolved from prehistoric grasses between thirty and forty million years ago, long after the extinction of the di-nosaurs. It then became the major food source for herbivorous animals, eventually becoming a food source for the modern human being as well.

Major bamboo research didn’t begin until 1920, when the history of the plant was studied. It has shown that there are native species of bamboo al-most everywhere, including the United States. It is now used widely in landscaping, but bamboo grows in two styles, clumping and running, which make it a widespread plant that can easily take over a gar-den if not cared for properly.

While bamboo was used frequently in the eastern hemisphere for housing for centuries, it is now only becoming popular in the western part of the world. More and more architects are seeing the beauty and intelligence in using bamboo for structures and other building material, and are becoming famous from the use of it in buildings.

2.2 BAMBOO


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Phyllostachys edulis ‘Jaquith’ Bamboo(Common Name: Moso bamboo)

Maximum Height : 20 metresTypical Height : 12 to 15 metresDiameter : 12 cmHardiness : 0° FClimate : temperate

This is the largest of the hardy bamboos and one of the most beautiful. The very large culms are fes-tooned with masses of the smallest leaves in the Phyllostachysgenus, making it look even larger. The culms of a mature plant are very broad at the base and quite tapered.

week 2 week 4 week 6 week 8 week 10 week 12

5m

10m

15m

20m

shoot

Figure 11 - Diagram of lifecycle of bamboo

2.3 LIFECYCLE

The oldest bamboo house, Peru, South AmericaThe earliest known example of bamboo used in construction. Used as reinforcement within the walls it has also been speculated that it formed the roof frame.

Flute of the Tomb of Marquis Yi of Zeng, ChinaThe earliest extant Chinese transverse flute It is fashioned of lacquered bamboo with closed ends and has five stops that are at the flute’s side instead of the top.


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2.4 Timeline

Rammed Earth

Bamboo

7000 BC

Mud brick and adobe housesdiscovered in Kazakhstan

1000 BC

Temple of Ramses II, Gourna, Egypt The temple was constructed from rammed earth blocks

Bamboo Dragonfly, ChinaThis helicopter-like top originated in Warring States period China around 400 BCE, and was the object of early experiments by George Cayley, the inventor of modern aeronautics.

The Persian Abacus, Persia, IranThe earliest known abaci constructed as a bamboo frame with beads sliding on wires. Un-der Parthian and Sassanian Iranian empires, scholars concentrated on exchanging knowledge and inventions by the countries around them

Bamboo Book, ChinaAs early as 600 BC, Chinese began to write on bamboo strips with brush pens. The strips would be strung together to make a kind of codex.


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700 BC

The Tower of Babel features in the book of Genesis where it is said the tower is made from bricks made from earth.

600 BC

Heuneburg Fort, Lake Constance, Germany The fort is the oldest example of earth building in Northern Europe.

500 BC

The citadel of Arg-e Bam, Iran The ancient citadel dates back to the Parthian Empire but most buildings were built during the Safavid dynasty.


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100 BC

The Bazaar Quarter, Sirdjan, PersiaWith other construction materials being hard to come by the population built an entire city out of earth without the use of any formwork.

200 BC

Hans Watchtower, Dunhuang, Gansu province, ChinaThe fort is the oldest example of earth building in Northern Dunhuang was one of four frontier garrison towns and the watchtower is constructed en-tirely from rammed earth.

The Duijang Dam and irrigation system, ChinaThe levee portion of the structure was constructed using long, sausage-shaped baskets of woven bamboo filled with stones.

300 AD

Sun Pyramid, Teotihuaca, MexicoThe central core is constructed of around 2 million tons of rammed earth.

Bamboo Oil drill, ChinaDrills were constructed us-ing bamboo. Pandas were an incredible nuisance and con-sumed countless rigs.

Bamboo and silk kite, Chinat was recorded that a Chinese Philosopher, Mo Zi, spent 3 years making a hawk from wood which flew.


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1800 AD

Earth House, Weilburg, Germany The house is six storeys high and still inhabited today.

2000 AD

Nk’Mip Desert Cultural Centre , British Columbia, CanadaSuccessive layers of differently colored local soils were placed into the 600mm wide formwork . Architects: Hotson Bakker Boniface Haden architects + urbanistes.

Mosque, Djenne, MaliThe Mosque is the largest mud brick building in the world and is considered by many architects to be the greatest achievement of the Sudano-Sahelian architectural style, albeit with definite Islamic influences.

Qian-Xian Bridge, ChinaThis narrow bridge still standsdue largely to continuous maintenance.

1000 AD

Las Piñas Bamboo Organ, Las Piñas City, PhilippinesThe pipes are made almost entirely of bamboo. It was completed in 1824 by Father Diego Cera

Wind and Water , VietnamArchitects Vo Trong Nghia have constructed a thatched bamboo dome at the centre of a lake in Binh Duong Province.

32Figure 9 - Image showing community school by Anna Heringer

3.1 Rammed Earth

MODERNDEVELOPMENT


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Figure 10 - Image showing rammed earth house by DUST Architects

Rammed earth building is not new, it has been around for thousands of years and some of these buildings are still around today, so we know there-fore that earthwall buildings can be made and main-tainted to last, and to provide safe shelter. On the other hand it is also true that many rammed earth buildings do not last the test of time, and it is this section where we show how to build properly with rammed earth and maintain it correctly.

Experience has shown that rammed earth cures more slowly than concrete with some taking up to 2 years to be fully dry and reach its maximum com-pressive strength. Each earth wall will have differing proportions of soil so the strength of the finished wall can vary by 30% or more depending how the quantities of clay and stabilising element used.

Figure 11 - Image showing rammed earth house by DUST Architects


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Structural Bamboo has been brought into the modern age by Maui-based Bamboo Technol-ogies. In conjunction with the International Bamboo Foundation, the Environmental Bam-boo Foundation, and The International Net-work for Bamboo and Rattan, Bamboo Tech-nologies modernized an ancient process using a pressure and vacuum chamber and a simple borate (salt) solution. The borate permeates the bamboo and is unpalatable to beetles and termites that would otherwise love nothing better than to feast on the sugars and starch in untreated bamboo.

With proper protection from the elements, us-ing a marine grade varnish, the same as wood requires, the borate does not leach out over time and the Structural Bamboo has a useful life expectancy as long as any commercially available building material. By way of example, there’s an entire properly protected bamboo village in Belgaum in southwestern India built in the 12th century that stands intact today.

BAMBOO3.2


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All of this research and testing bore fruit when, in 2004, the Structural Bamboo poles as produced by Bamboo Technologies were certified by The International Code Council (ICC) as complying with International Build-ing Code (IBC), International residential Code (IRC) and Uniform Building Code (UBC) stand-ards. This opened the door for the use of Structural Bamboo by architects and builders in modern building code approved residential homes and many commercial structures any-where in the world.

Bamboo Technologies also pioneered several methods of joining bamboo poles together to deliver complex structural elements and trusses that allow a wide range of elaborate architectural designs for a variety of high stress applications. (More on that in a mo-ment when we talk more about hurricanes.)

Figure 12 - Image showing community school by Anna Heringer

Figure 13 - Image showing unique bamboo church


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3.3.1 USE IN UNITED KINGDOM

Although the combined numbed of UK rammed earth and stabilised rammed earth structures is presently believed to be no more than several hun-dred, the last decade has seen a significant renewal of interest, driven primarily by the demands for more sustainable building. Over the past 25 years a few thousand stabilised rammed earth buildings have been built in Australia.

Recent applications of rammed earth in the UK have been varied, including visitors centres, a sports hall, a business park development, a children’s nursery, a conference centre, as well as a prize winning exhibition wall at the Chelsea Flower Show. New rammed earth projects currently under develop-ment include the Genesis Project at the Somerset College of Arts and Technology in Taunton.

There are considerable opportunities for the devel-opment of rammed earth in the UK in the forseea-ble future. The technique offeres a high quality and sustainable building method suitable for a range of applications. Forms and finishes in rammed earth are wide and varied.

Though the project behind the development of this guide has taken significant steps forward in under-standing material performance, many questions re-garding rammed earth remain unanswered. Ther-mal performance, wider benefits of hygroscopic behaviour and breathing wall construction require

further study in relation to rammed earth. One day a simple and reliable test to evaluate weathering resist-ance performance might even be developed.

RAMMED EARTH

Figure 13 - Photographs of rammed earth at The Eden Project


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3.3 .2 USE IN UNITED KINGDOM

The bamboo currently used in the United King-dom in transported from namely China and Co-lombia but this can still be regarded as a cost and energy factor, it should be noted that unlike wood, the harvesting and processing of bamboo requires very little energy; the material is very lightweight and when transported by boat, caus-es comparatively little environmental pollution. The ecological footprint of imported bamboo is therefore generally thought to be lower that that of wooden profile.

Due to studies conducted at the University of Bath and University of Cambridge it is now wide-ly believed that certain bamboo species could be grown in the United Kingdom. One of these species is Phyllostachys Pubescens (Moso) which is what we are planning to use. This species is normally grown in temperate climates already and can withstand temperatures to -25 degrees celcius making it ideal for Scottish climate as the lowest temperature recorded in Scotland in the last few years was -22.3 degrees celcius in Altna-harra in 2010.

In the United Kingdom there are no building regu-lations for the use of bamboo as a building struc-ture primarily because it is not a certified building material. Tests for structural qualities are done on a project to project basis with nothing recorded. This is perhaps the first area that could be looked

into to start the beginning of building regulations for bamboo.To promote wider use of round culm bamboo in construction, INBAR and Coventry University have also now commenced another international re-search project with partners in Colombia and Ec-uador. The project aims to develop new, quick and relatively cost-effective ways of determining the strength grade of round culms using non-destruc-tive mechanical tests. As David Trujillo, the prin-ciple investigator and senior lecturer at Coventry University explains, “At present, we can only infer the strength of bamboo culms used in construction from destructive batch tests that are conducted on a small sample of bamboo, while visual grading for bamboo is not scientifically-based. Therefore, the current status quo for round pole bamboo con-struction means the material is either used very conservatively in buildings or, alternatively, it is not used conservatively enough.” Therefore, mechani-cal strength grading of bamboo culms can poten-tially improve connection design and make build-ings safer.

BAMBOO


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STRUCTURAL CHARACTERISTICS

4.0 BAMBOO

Figure 15 - Image showing bamboo scaffolding

A bamboo cane has a high resistance to ten-sion, especially in its external layer. This layer bears up to 40kn/cm2. This therefore in a weight to weight ratio reaches the strength of steel.

The compressive strength of one node of a bamboo cane depends on its diameter. Generally speaking the compressive strength is equal to 1,840kN / cm2. This is therefore almost double that of wood and most com-parable to concrete in a weight to weight ratio.

The main element to pay careful attention to when constructing with bamboo are the joints, as the nodes are the strongest points on the plant. Tying with natural rope is by far the most common as it does not perforate the cane and can be done by anyone. More modern methods include using steel shoes or plates and bolts but this means nailing laterally though the cane which reduces the overall compressive strength.


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STRUCTURAL CHARACTERISTICS

4.1 RAMMED EARTH

Figure 14 - Image showing reinforcement bars inside earth wall Figure 15 - Image showing earth tampering

Rammed earth can mainly be treated liked concrete for its construction and mainte-nance and although its structural qualities are similar it needs to be looked at separate-ly.For example the minimum thickness of a load bearing rammed earth wall needs to be at least 300mm thick whilst it must also be suitably restrained at the top and bottom for heights over 2.4m to maintain the compres-sion in the layers.If these guidelines are fol-lowed the compressive strength of load bear-ing rammed earth construction is expected to be no less than 2 N / mm2.

For our project we have decided to combine the two materials as this will produce the highest compressive and tensile strength. Therefore, the rammed earth wall are reinforced with bamboo canes 30mm thick to provide vertical reinforcement. The walls have been built up in horizontal layers and therefore the lateral resistance is high enough without reinforcement. We also used natural twine to tie the bamboo as this con-tracts when wet producing a tighter knot and therefore a stronger structure. For the roof covering we are using bamboo screens which allow wind to pass through, therefore limiting the effect of wind suction caused by strong gales.


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5.1 QUARRY VISIT

PRE - WORKSHOP

Figure 17 - Photograph of machinery used to filter earth

Due to their being a limited amount of soil on site and not wanting to hire a digger we had to source the soil for the rammed earth walls ourselves. We managed to do this with the help of tillicoultry quarry who provided the soil to us free of charge.

We decided to go to the quarry to speak to the op-erators and take a few samples so we could carry out tests and make sure the soil was of suitable building standard. During our visit we saw how the soil was taken from the cliff, how it was processed and how it is then loaded for delivery to its final destination.

Finding the correct soil was a key element in our project. During our research we found that if soil is not available on site then it should be sourced lo-cally to avoid transport costs and emmissions. The quarry was less than one hour away from site and so made transport easy and with low carbon em-missions.

The best soil to use for rammed earth construction is called ‘Quarry Fines’ as it has the perfect concen-tration of clay, silt, sand and gravel. Quarry fines are actually a waste product which means we are help-ing cut the waste from the quarry.

5.0


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Figure 18 - Photographs showing our visit to the quarry


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5.2 SOIL TESTS Jar Test (Instructions)

Place about 2 cups of soil to be tested into a quart jar. Fill the rest of the jar with water,shake it unitl all of the soil is in solution, and then let it stand for a few hours or until the water is clear. The sand parti-cles will settle to the bottom more quickly because they are heavier. The silt and clay will settle out more slowly, resting on top of the sand. The line between the sand and the clay/silt layers should be clearly visible.

By measuring and comparing the thickness of the two layers, you can roughly determine the ratio of

fine to coarse particles.

If the layer of fine particles is roughly one-half to one quarter as thick as the layer of sand, then the material can be considered a contender in the suit-ability contest.

Soil suitability experiment - field test

This simple test can quickly identify whether a soil contains the suitable ratios of gravel, clay and sand to construct a rammed earth wall.

1. fill the jar half full with soil.

2. add water until the jar is full.

3. shake well and allow to settle for 24 hours on a flat surface

Jar of water and soil mixture before allowing to stand for 24 hours.

Jar of water and soil mixture before after standing for 24 hours.

clear layers visible:

gravel

sand 70%

clay 30%

water

Figure 19 - Diagram showing jar test


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Figure 20 - Photograph showing our experiment


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Test Block

The next test is called a ‘test block’ which deter-mines the texture and colour of different samples and can be subjected to accelerated exposure and weathering tests to determine how the walls will hold up over time and how they might lok after a

Instructions

The test blocks are made in a wooden form held together with 75mm bolts. The small wooden form is made of the same components as the full-size wallbuilding form, with the exception that walers are not required if the block is 300mm or less in width. The block should be about 300mm X 400mm X 90mm thick. These would then be left outside, wetting and drying in the rain. If a test block begins to erode when subjected to heavy spray from the hose, then this soil should not be used for building in Scotland.




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5.3 MATERIALS

Figure 17 - Photograph of machinery used to filter earth

This is a selection of photo-graph’s showing the materials we would be using on site.

Left: 50 used scaffolding boards obtained from glasgow wood recycling centre.

Below: 64 Bamboo poles.

Top Right: Cutting of bamboo poles.

Below Right: 2 Cement mixers and behind 15 tonnes of quarry fines.


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Figure 18 - Photographs showing our visit to the quarry


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Tuesday 5th

August

activity

objective

9.00am

Preparation for workshop

10.00-10.30 Introductory

PowerPoint presentation

• Give students some information about ourselves, PgDip, Ecuador trip and talk about rammed earth and bamboo construction.

10.30-11.15 Survey the site • Take students to the site to measure and draw up dimensions. Talk about what the space could be.

• Put students into groups of 4 or 5. Each group split into two one half measuring and 1 half recording measurements.

11.15-11.30 Comparing findings and measurements

• Have a look at the differences between the findings of each group and how they have recorded the measurements.

11.30-12.00 Developing the brief +

introduce design competition

• Post it note brain storming to ask the following questions; Who, Where, What, When, How Why, Strengths, Weaknesses, Opportunities and Threats

12.0-1.00

Lunch

1.00-2.00 Rammed earth

experiment (medium scale)

• To get hands on experience with the process of building with rammed earth before the 1.1 build.

2.00-3.00 Sisal twine and rope tying

(medium scale)

• Using the twine and tope to connect bamboo poles in different ways in preparation for 1.1 build.

3.00

Finish

5.3.1 SCHEDULE design workshop


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Wednesday 6th

August

activity

objective

9.00am

Preparation for workshop

10.00-10.15 Turn out rammed

earth samples • Observe qualities of rammed earth;

strength, aesthetic.

10.15-12.00 Design workshop- (small scale)

• Using small dowels and clay.

12.0-1.00

Lunch

1.00-2.00 Work on

presentations for competition

• A2 posters with drawing of design. • Verbal presentations of why their design

should win.

2.00-3.00 Group presentations &

Select winning team for competition

• Students will present their designs to the group.

• The winning design will be chosen by the group for the 1.1 scale build.

3.00

Finish


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DESIGN WORKSHOP6.1 DAY ONE

52Figure 9 - Photograph of students with bamboo poles

This marked the beginning of our interaction with the young adults. We had arranged with North Lanarkshire council to run a workshop involving their Activity Agreement Programme which aims to provide employability skills for 16-19 year olds.

We started off the workshop with a brief introduc-tion using powerpoint presentation, telling the stu-dents about ourselves and how we had come to undertaking this workshop. The next step was to inform the students of basic design techniques and ask them to think about what they would like to build.

Before we could do this though we had to teach them the construction methods we were going to use. This involved showing them how to mix the soil, construct the formwork, put the soil into the formwork and compact it using a tamper. We also showed them how to connect bamboo using natural rope which is a simple technique but must be learned properly before going on site.

Below are a selection of photograph’s from the workshop.


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DESIGN WORKSHOP


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WHO WHAT

YoungMums

16 + GROUP

Mother and toddler

group

The community

WHY

Relaxation space

Build a place for children to play in

Flexible learning

space

outdoor classroom

gardenallotment

Afort

Bamboo igloo

a Wendy House

treehouse

Concert area

secret gardenIDEAS

PROS CONS HOW

Large footfall

Raised flower beds

Sunny Aspect

Slope on site

Ugly Fence

No Views

Surrounding Buildings

Onlyfire escape or

external access to site

Rammed Earth

Bamboo

SisalTwine and

rope

Willow

IDEAS


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building with rammed earth and bamboo in scotland

DESIGN WORKSHOP6.2 DAY TWOThe topic for day two was design, by the end of the day we wanted to have as many designs as possible from the students from which we could base our final design.

We began by splitting the students into groups and gave them some materials to use to build models of their designs. The materials we gave them were: bamboo skewers to replicate the bamboo posts and clay to replicate the rammed earth. During this process we went around the groups and helped them with their models and also gave them some ideas on their designs.

At the end of the day we asked the students to make posters of the ideas and then we finished with the students presenting their designs to the group. This led to a discussion determining what the best aspects of everyones designs were that we wanted to utilise in our final design. We had an anonymous vote to see which design everyone liked the best. This was a really good experiment as it made the students think outside the box and us-ing their experience from the day before they were able to come up with some really exciting designs.


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DESIGN WORKSHOP


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6.3 FINAL PRESENTATIONS


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6.4 SCALE DRAWINGSFrom the students designs we discussed with the centre staff different options for the design. Our main objective was to incorporate different ele-ments from each design so that everyone could identify with the final proposal. Additionally we tried to create as much or a transformation of the space as possible.

By doing so we created a central rammed earth structure, with pitched bamboo roof to act as the main gathering point in the scheme. The surround-ing bamboo pergolas were suggested as a way of incorporating the existing raised beds and framing the space; in order to break up the monotony of the site.

Before the start of the Build Workshop we present-ed the design proposals to the students and staff as a short animation.

SECTION A - through central hut1.100


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SECTION B - through raised bed1.100

SECTION C - through turf bench and pergola1.100

PLAN -1.100

ELEVATION - 1.100

A

A

B

B

C

C


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LIVE BUILD WORKSHOP7.1 D

A Y O N E

The ‘Live Build Workshop’ began with us giving the students a presentation showing them the final de-sign in a computer generated 3D model and some Cad drawings.

We asked the students for their feedback and then proceeded to explain the design and how we would go about building it.

Day one simply involved preparing the site for building to begin and setting up the formwork for the first wall and then filling the bottom couple of layers to let the students gain an understanding of the process at 1:1 scale.

Another team was set the task of tying all the wil-low into bundles which could then be used on the roof of the pergola.


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A Y T W O

Day two is where the real work started, here we be-gan making the foundations for the pergola struc-ture to sit in. This consisted of one layer of rammed earth which the bamboo columns would then sit in and dry overnight to become solid.

Some foundations were dry enough by the after-noon and so tying could begin on the pergola. An-other team also continued work on the first main wall. This was a much harder task as it involved physical labour, shovelling soil into the mixers and then into the formwork. This was then tampered down to create a solid wall.

By the end of day two we had one pergola set up and 3/4 of the first main wall finished.


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73Building with Ramed Earth and Bamboo in Scotland

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A Y T H R E E

Day three was a hard day in terms of wall construc-tion. It rained non-stop the whole day which made work very difficult and kept morale low through-out. We did manage though to finish off the first main wall and get another pergola constructed on the opposite side.

Meanwhile another team were cutting the willow bundles to size in order to be tied onto the pergola to create a roof covering.


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A Y F O U R

Day four was a very successfull day, we had clear skies throughout and even some sunshine which made the whole build process much quicker.

The majority of this day was spend on the two side walls of the main building. First the formwork was set up on each side using the scaffolding boards and the f-clamps. Next there was a team preparing the earth mixture by putting soil, lime and water into the mixers for approximately 10 minutes.

These mixes were then taken over to the wall and shovelled into the forms in equal measures and tampered down. We alternated each wall we worked on so that it had time to dry before the next layer was applied.


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A Y F IV E

Day five was another good day, here we finished off the two side walls and completed the pergola structure enabling a team to start tying the willow bundles to the roof beams.

There were another two teams working on the wall, one mixing and one setting up the formwork and tampering.

By the end of day five the team could really see the design coming to fruition which helped keep morale up which had started to fade due to all the intensive labour.


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A Y S I X

Day six signalled the removal of the formwork from all the walls and the beginning of the roof construc-tion.

Lindsay and I worked on the roof construction as this was the most technically difficult element of the whole build while some students watched to learn how to do it. The roof was the most complex task but I think it really makes the project.

Whilst we were working on the roof, another team focused on finishing off tying the willow bundles onto the roof of the pergola which really brought them to life.

Under guidance from Lindsay and I the community centre decided to use some of their fund to buy grass to put underneath the pergola’s which I think give a much nicer and friendlier feel to the space.


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A Y S E V E N

This was the final day of our ‘Live Build Workshop’ and by this time the whole team was exhausted mentally and physically of doing hard physical la-bour and in some really horrible coniditions.

The last tasks to complete on day seven were to fin-ish off the roof covering, water down the grass, fill in the gaps between the planters (one with rocks and the other with a grass seath) and move all the left over soil.

It was tough moving all the soil but after the site was cleared up we got our first real glimpse at the whole build project which the community centre were delighted with. It transformed an otherwise dull and useless space into a space that will be used for activies such as, barbques, gardening, festivals, talents contests and even just getting out of the rain.


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OPENING CEREMONY8.1

On Friday 22nd of August the Airdrie at Home Centre held an Opening Ceremony for North La-narkshire council representatives, local press and friends and family of the students. The reaction to the project was fantastic with many amazed by the scale and quality of the build carried out over such a short period of time. The students were proud of their achievement and the response from their families.

“what has been achieved here has taken a unused space and made it into a place”

Raymond

During the day plans for the possibility of similar projects for the North Lanarkshire allotments was discussed. It seems that everyone involved and who came to see the final outcome was fully on board with the project and realized the potential of rammed earth and bamboo as a viable building material in Scotland.


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LEARNING OUTCOMES

8.2

LEARNING OUTCOMES


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REFRENCESBOOKS

Easton, David. 1996. THE RAMMED EARTH HOUSE. Chelsea Green Publishing Company: Vermont.

Minke, Gernot. 2006. BUILDING WITH EARTH, DESIGN AND TECHNOLOGY OF A SUSTAINABLE ARCHITEC-TURE. Birkhauser: Berlin.

Minke, Gernot. 2012. BUILDING WITH BAMBOO, DESIGN AND TECHNOLOGY OF A SUSTAINABLE ARCHITEC-TURE. Birkhauser: Basel.

Walker, Peter. Keable, Rowland. Martin, Joe. Maniatidis, Vasilios. RAMMED EARTH ; DESIGN AND CON-STRUCTION GUIDELINES. BRE bookshop:2005

WEBSITES

GIANT GRASS DESIGN - http://www.giantgrassdesign.com

BAMBOO DESIGN AND CONSTRUCTION - http://www.bambooroo.net/

ECOBAMBOO – www.ecobamboo.net

SCOTLANDS SOILS - http://www.soils-scotland.gov.uk/

GUADUA BAMBOO - http://www.guaduabamboo.com/

RAMMED EARTH - http://www.rammed-earth.org/

THE BAMBOO SOCIETY OF AUSTRALIA – http://bamboo.org.au/community/

MOSO - http://www.moso-bamboo.com/company

BAMBOO BOTANICALS - http://www.bamboobotanicals.ca

RAMMED EARTH CONSTRUCTIONS - http://www.rammedearthconstructions.com.au/

community live build project

Documents

rammed earth building

qualities of rammed

ramed earth

design workshop

workshop reporta workshop

build workshop

airdrie learning centre

design competition