contents...2012/12/02 · steel with the compressive strength of concrete, resulting in a product...

P0048459 Learning Resource S1, CPCCBC5004A, Ed 1 1 of 51

© State of New South Wales, Department of Education and Communities 2011 Version 2 December 2012

Contents

Contents 1

Introduction 3

Factors affecting the selection of building materials 4

Economic factors 4

Physical properties 5

Factors affecting the performance of materials 10

Movement caused by applied loads 10

Movement caused by temperature 10

Movement caused by moisture 11

Durability 12

Fire resistance 14

Compatibility of materials 18

Testing of materials 20

Handling and storage 22

Bricks and concrete blocks 24

Timber 24

Concrete 25

Glass 26

Tolerances 26

Activity 1 28

Quality standards and requirements 29

Materials and standards 30

Compliance and safety 31

Selecting building materials that consider the environment 32

Use durable products and materials 32

Choose low-maintenance building materials 33

Minimise packaging waste 33

Environmentally friendly materials 33

2 of 51 P0048459, Learning Resource S1, CPCCBC5004A, Ed 1


Use local materials 38

Products that reduce the quantity of material used 38

Recycled or salvaged products 38

Products with recycled content 38

Certified wood products 39

Natural or minimally processed products 39

Alternatives to products made with environmentally hazardous components 40

Products that reduce environmental impacts of building 40

Identifying suitable products 43

Life-cycle assessment analysis 43

Onsite application 43

Material Defects 45

Timber 45

Stone 45

Defects after installation 46

Defect indicators 46

Deterioration 47

Preserving timber 48

Protecting metal - steel 49



Introduction

Welcome to Supervise and apply quality standards to the selection of

building and construction materials CPCCBC5004A.

In this module you will learn about the characteristics and quality standards

of building materials commonly used in buildings—knowledge that will

help you select the most appropriate materials for your work.

We will examine a wide range of building materials: timber and timber

products, concrete and concrete products, clay and stone, mortars, plaster

and plasterboard, metals and glass, paint and coatings, plastics and

adhesives and alternative materials. Before we examine each of these

materials you will need to know what affects the performance of building

materials in general. This is what you will study in this first unit.

There is a wide range of possible building materials available for our use

and the performance of these materials has an impact on the cost, aesthetics

and function of the building.

A well designed, economical building takes the following factors into

account:

the properties and behaviour of building materials

the initial and long-term costs

the effects on the environment

how the materials interact with each other.



Factors affecting the selection of building materials

The selection of materials is affected by a range of factors including:

economic

physical.

Let’s examine these factors in detail.

Economic factors

Energy content

Building materials are sometimes described as having a certain ’energy

content’. This refers to the cost of their production. Stone (for concrete

aggregate), timber or sand are materials having a ’low energy content’; that

is, they do not require a primary manufacturing process. Some materials

which are by-products of other industrial processes (e.g. wood particles,

blast furnace slag and pulverised ash) also have a low energy content.

Materials with a low energy content are cheaper because energy has not

been used in their production.

Other materials require energy in their production, and therefore have a

’high energy content’. These include, for example, glass, bricks, plastics,

metals and cement. This adds to their cost, and if local supplies of the raw

materials are exhausted or unavailable, then purchase and transport costs are

also added to the overall cost.

Labour and material costs

The initial cost of building will depend almost entirely on the costs of

materials and on the labour costs.

The cost breakdown for housing construction is roughly:

55 per cent materials

45 per cent labour.

The choice of materials should not depend only on the purchase and

installation cost, but also on the cost of repair, maintenance and replacement

of short life-span products. Less durable materials may be cheap to buy but

repair or replacement costs are usually high.



Cheap materials usually lower the value of a building, whereas more durable

materials, such as stone and brick, mellow with age and give the structure a

more aesthetic appearance.

Conservation of resources

Most world resources of metals, rainforest timber, fossil fuel and limestone

are non-renewable and limited. It is important for us as consumers not only

to be aware of those resources which are threatened or have bad effects on

the environment, but also to use those which are, with management, safe

both to our health and to the environment as a whole. Where possible we

should use renewable resources, such as timber from re-planting programs.

It is also important that world fuel energy is not wasted by unnecessary

processing and transportation. As well as being environmentally desirable,

these savings mean cheaper materials.

Physical properties Materials have different characteristics, or properties. These properties are

affected by physical, chemical and biological factors.

Here we will be looking at the following properties:

density and specific gravity

strength

electrical conductivity

thermal conductivity and capacity

moisture absorption

acoustics

Properties that relate specifically to certain building materials will be looked

at in later units where the particular building material is dealt with at length

(e.g. optical properties will be dealt with in the unit on glass).

Density and specific gravity

Different substances have different densities. Iron is much denser than

aluminium which is why a piece of aluminium is much lighter than a piece

of iron of the same size. Ice floats in water because the ice is less dense than

the water. Density is measured as mass (kg or tonnes) per unit volume e.g.

kg/m3.

Specific gravity is the ratio of the mass of a given volume of a liquid or

solid to that of the same volume of water. The density of pure water is taken

as 1 t/m3 at 4°C.



Strength

A structure (e.g. a beam or a bridge) must be able to safely support its own

weight plus the load it carries without distortion. Distortion will reduce the

efficiency of the structure or make it break or look unattractive.

A structure can be made much stronger for a particular role without

increasing its weight, by being made in a different shape. For example, in

Figure 1, where the steel beam A is much stronger than the steel beams B or

C for a given bending moment, even though they all contain the same

amount of steel.

Figure 1 - Different types of steel beams

Some materials strongly resist being squashed. They are said to have high

compressive strength. Concrete, stone and brick are such materials. Other

materials, such as steel, are strong under tension and will resist being

stretched.

The behaviour of concrete in bending is illustrated in Figure 2. Concrete

cracks easily when stretched. It has low tensile strength.

Figure 2 - The concrete slab is strong under compression

By using steel reinforcing in concrete, we combine the tensile strength of

steel with the compressive strength of concrete, resulting in a product that is

strong in tension as well as strong in compression (see Figure 3).



Figure 3 - The tensile (under tension) strength of steel is combined with the

compressive strength of concrete when reinforcing mesh or bars are used in

concrete

A piece of 25 mm wide galvanised steel strap, which is often used in

bracing timber frames, is very difficult to stretch, but crumples easily when

compressed lengthways. It has high tensile strength and low compressive

strength.

Materials that are subject to force are said to be stressed, and change in

length or cross sectional area is called strain. An elastic material is one

which will recover its original shape when the stress is removed. A steel

spring is elastic. A piece of chewing gum is not very elastic.

The response of materials to stress will depend on:

how stress is applied to them (suddenly or gradually)

whether the stress is continuous (e.g. a load-bearing arch)

whether the material is compressed, stretched or twisted

whether it is affected by moisture or temperature.

Structural requirements

Of central importance to building designers is the relative performance of

building materials in terms or both strength and cost. Of similar importance

is the architectural appearance if exposed to view. Designers select

structural materials from a range of options, including client parameters

relating to budget.

Commonly available building materials are mass produced and as a result

cheaper than less common materials. For example the cost per meter for F5

or MGP10 pine which is commonly available is substantially less that the

cost of F14 hardwood. However more economical buildings are possible

using steel due to steel superior structural performance even though steel is

more expensive than timber per meter. D range of structural solutions are

now available, including structural flooring systems and wall systems, for

those builders able to choose and select between structural design options.

Building structures resist a range of applied forces. These may be static such

as due to the weight of the structure or dynamic due to the weight of people

or the wind. It has been found that by using structural materials in

combination more economic outcomes are possible. As a result you will

often see a thin surface material supported by rows of structural framing that

is further sported by additional rows of larger framing spaced further apart.

For example consider battens, rafters and underperlins in a conventionally

framed roof or sheet flooring over rows of joists over rows of bearers.

The structural performance of materials will be determined by either the

relevant building code or standard or the contract specification. Sometimes

builders will be given a choice of structural materials however more

typically this will be already determined by the designers. Substitution due



to non-availability is more common but usually with most contacts will

require the client's prior agreement.

Choices will always exist and the cost impact on the design determine. For

example 20N and 32N concrete. Or F5 or MGP10 timber framing.

Electrical conductivity

Materials that easily carry electricity through them are said to be conductors.

Materials that do not are non-conductors. For example, most metals are

good conductors and most plastics are not. This is why electrical wiring is

copper and the protective sheathing is plastic.

Thermal conductivity and capacity

The thermal properties of a material are concerned with how a material

reacts to changes in temperature. The thermal properties include heat

expansion or contraction, insulation, heat storing ability, cooling, and

reaction to frost, snow and ice.

Thermal conductivity is a measure of how fast heat travels through

materials. This rate may be affected by density, temperature, porosity and

moisture content.

For example, a building material that has a moisture content of 20 per cent

will lose two to three times more heat than when it is dry.

Thermal capacity is the ability of a substance to store heat. A brick or a

stone wall, for example, will heat up slowly, hold the heat and lose it slowly

as the outside temperature drops. A thin, light wall, on the other hand, heats

and cools quickly and does not provide a buffer to the climate. Underground

houses provide an ideal thermal situation because the surrounding soil

slowly heats up during summer and is warmest in winter; it then gradually

loses heat again so that, by summer, the soil temperature is cooler than the

outside air.

The choice of materials of various thermal capacities will depend on the

type of climate and the use to which the building is put.

Moisture absorption

Some very porous materials will absorb moisture more readily than others.

However, most materials may take up moisture from the air, from the

ground (e.g. through poor dampcourses), from damaged roofs or gutters, or

by condensation.

Condensation of moisture in the air will form tiny droplets on surfaces

colder than the air. In the past, traditional building methods allowed water

vapour to travel out of the building. Nowadays, however, condensation

often becomes trapped on the inner surface of water-tight materials (e.g.

flat-roof coverings, metal and glass wall-cladding, foil insulation). This can

be prevented by the correct use of vapour barriers (materials which are



designed to prevent surface condensation by being placed on the warm side

of walls or ceilings in such a way that there is no gap in them).

Acoustics

Insulation from noise can be achieved by the use of dense materials, by

avoiding openings directly onto noisy areas and by avoiding direct paths

(e.g. a hall with a bend leading from a noisy machine shop to the workers’

tea room or a hall with lobbies or double doors would reduce noise).

Some porous materials are used for modifying the acoustics in a room but

sound can only be prevented from travelling from one space to another by

the use of dense materials or a vacuum.

On the inside of a building, double-glazed windows, heavy curtains, wall-

hangings and carpet all help absorb noise. On the outside, walls, fences,

hedges, trees and bushes may be used to reduce traffic or industrial noise.



Factors affecting the performance of materials

Building materials undergo changes over time and the following factors

affect their performance:

movement caused by applied loads

movement caused by temperature

movement caused by moisture

durability of the materials

fire resistance

compatibility of different materials

Movements may be substantial and result in considerable stresses. If these

stresses are greater than the strength of the material then, obviously, cracks

or failure will result.

Movement caused by applied loads These movements are normally allowed for in design but excessive

movements may be caused by poor structural design or from accidental

overloading.

Movement caused by temperature Most substances are affected by temperature changes, expanding when

heated and contracting when cooled, but some are affected more than others.

This is called thermal movement. Figure 4 shows a comparison of the

relative changes due to temperature in a number of materials.

Dark coloured materials set into light coloured ones

Dark coloured materials, when exposed to the sun, can heat up and expand

greatly, causing cracks in the material in which they are set. Or else the dark

materials may themselves crack or buckle. For this reason, roof surfaces

(such as sheet metal) are best finished with a solar heat-reflecting surface or

paint. Coloured glass in a sunny wall must be able to move freely, as it will

expand and contract with temperature changes. If the glass is set between

metal screws or beading that prevents this movement, it will crack. Putty or

silicone caulk allows such movement.



Long walls

Long walls must be allowed to expand in every direction. Movement joints

are placed at recommended intervals. A long wall butted up to buildings at

each end may distort, causing cracks. The wall could also fail at weak

points, such as over archways or doorways. If the wall itself does not give

under the pressure, then it could cause cracks or bulges in the walls that it is

butted up against at each end.

Figure 4 - Relative changes in the sizes of various materials due to thermal

movement

Movement caused by moisture A change in the moisture content of most materials will result in

deformation: they will swell when wet and shrink when dry. These changes,

called moisture movements, can result in warped, twisted, shrunk or cracked

items.



Durability Since all materials deteriorate over time to some extent, we should be able

to anticipate these changes and take them into account when designing a

structure, whether it is a house, a shed or a cupboard. We should foresee

normal wear and tear, as well as the occasional very heavy stress caused by

storms, fire, flood or burglary for example.

Durability will be different for different exposures. A coat of paint will last

for many years inside a cupboard or less than a year in a sunny exposed

position in a heavily polluted industrial area. We are all aware of the effect

of salt spray on a car. Buildings are similarly affected, though it is not

always so obvious.

Direct and indirect causes of deterioration include:

corrosion of metals

sunlight

biological agencies

water and frost

salt crystallisation

chemical action and the loss of volatiles

abrasion and impact (wear)

vibration

fire

Corrosion of metals

Deterioration of specific metals will be examined later, in the unit on metals.

The effects of metal deterioration on surrounding materials can be

significant, and will be looked at in the context of these materials when they

are dealt with in later units.

Sunlight

Sunlight causes drying and cracking of timbers. It also fades colours and

pigments and its heating of dark coloured materials can greatly speed up

their breakdown.

Ultraviolet radiation causes breakdown of clear finishes, stains, paints,

rubber, some plastics and polyethylene, tars and bitumen, fabrics and

canvas.

Metals, bricks and stones are largely unaffected by sunlight.

Biological agencies

The destruction of timber by termites, borers and fungi will be discussed in

the unit on timber.

Certain bacteria in the soil break down sulphur chemicals which cause

corrosion of metals such as iron, steel and lead.



Burrowing animals or birds making nests can tunnel foundations,

undermining footings; they can also excavate loose unsound material

allowing rain in or weakening supports.

Tree roots and vines growing in cracks exert a very strong and destructive

force, expanding and extending cracks in masonry, pipes, concrete or

timber. They also hold moisture, encouraging the growth of moulds and

fungi, and the uneven drying of brickwork (which causes uneven

movements within the wall).

Water and frost

Care should be taken in the selection of materials for use in damp areas

since some building materials react less well in such situations than others.

For instance, limestone and marble slowly dissolve in water. Timber,

chipboards, hardboards and other similar wood products lose some of their

strength, and many flooring materials are less hard-wearing when wet.

Water can encourage fungal attack and certain destructive chemical

reactions. Repeated wetting and drying causes surface crazing and cracking

of timbers. Water also often carries destructive acids, salts and other soluble

chemicals.

Salt crystallisation

Salts that are dissolved in water can come from the sea, the ground and from

some building materials. As moisture evaporates from a surface, the salts

are left behind in the form of powder or crystals, called efflorescence.

Sometimes this is just an unattractive coating, usually white, but sometimes

yellow, green or brown. However, it can be destructive if allowed to persist

for a long time.

Salts crystallising on the surface of a porous material can cause gradual

erosion or flaking. This surface deterioration, called fretting or spalling,

often occurs in soft sandstones, bricks (such as sandstocks) or in mortar

layers in masonry. When moisture rises in the walls of a building these salts

cause paint to bubble and peel. Fixing this problem can involve costly

installation of dampcourses and removal of all affected plaster or render

from the walls.

Chemical action

Chemical reactions in materials can cause swelling, shrinking, weakness or

damaged appearance. This can be due to chemical changes within the

material itself, or changes brought on by attack from outside chemicals.

Heat and moisture aid most reactions.

The presence of aggressive gases, in the air or in factories or dissolved in

rainwater, can mean that some materials may need special protection, or that

other more suitable materials should be used instead.



Groundwater, industrial wastes, soil, ash and wet clays are some of the

substances that can produce soluble sulphates which attack cement products

and metals.

Loss of volatiles

Volatiles are liquids and gases. Plastics, paints, varnishes, finishes, mastic,

rubber, tar and bitumen shrink and become brittle when their volatiles are

lost.

Abrasion and impact

In situations of abnormal impact or abrasion, suitable materials and finishes

need to be chosen. For example, a concrete path or floor that will take heavy

traffic requires correct concreting techniques to be followed so as to produce

a hard, durable surface.

Vibration

Vibration caused by proximity to machinery or heavy vehicular traffic can

cause problems in light constructions and with brittle materials.

Fire resistance Fire is usually the fastest, most destructive and dangerous way in which a

building can be damaged or destroyed. It is a very important consideration

for both city and country dwellers.

Government bodies test materials and publish regulations and codes which

are implemented by local councils concerned about fire hazards in public or

private buildings.

Fire resistance ratings are also determined by laboratory tests. The ratings

indicate the time for a material to fail in a burning building. They are

usually expressed as hours or minutes.

Fire is a chemical reaction which needs fuel, heat and oxygen. Moist solids

and liquids give off vapour when they are heated and it is this which burns

as a flame. Solids can only burn at or near the surface. Open-textured

materials burn more quickly because they have more surface area, while fine

dusts (e.g. from coal, wood, flour, aluminium and many plastics) become

explosive when suspended in air.

In a fire, materials may melt, burn, weaken, expand, shrink or crack. Flame

and building collapse cause injury and death. However, smoke and gases are

equally dangerous (even when flames are not present), causing confusion,

unconsciousness, panic, loss of vision and asphyxiation. Solids can

smoulder in a confined space for a long time on only one-third of their

normal oxygen supply and then, on the sudden entry of air (a door being

opened, for example), burst explosively into flame. This is called flash-over.



Combustibility

Materials that ignite, that give off flammable gases or that show

considerable self-heating when exposed to a set heat in a furnace, are called

combustible.

Non-combustible materials, on the other hand, do not feed the fire, and

flame does not spread over them. Non-combustibility does not mean fire

resistance. Table 1 lists some combustible and non-combustible materials.

Non-combustible materials (such as steel) may expand and disturb attached

structures, or lose strength and collapse. Other non-combustible materials

may spall (flake) and shrink or crack. On the other hand, some combustible

materials (such as timber) can often provide a useful degree of fire

resistance.



Table 1 Some combustible and non-combustible materials

Combustible Non-combustible

timber fibrous cement products

cork compressed cement sheets

hardboard bricks

chipboard stones

wood laminates concretes

gypsum plaster board metals

bitumen felts glass fibre/mineral wool containing less

than 4–5% bonding agent

all plastics and rubbers

glass fibre/mineral wool with

combustible bonding agents

Fire resistance is expressed as the amount of time in hours and minutes a

component survives a fire test of set temperature before it can no longer

perform its function. It is considered to fail the test when any of the

following occur:

It collapses - (structural adequacy)

It forms holes or cracks through which flame can pass - (integrity).

It gets hot enough to ignite other combustible materials it is in contact with and which the fire hasn’t yet reached -

(insulation).

How certain materials behave in fire

Timber

Timber easily ignites at about 221–298°C. However, some timber

(particularly large pieces, at least 100 by 75 mm in section or larger) are

resistant to the fire once the surface has been charred. Many Australian

hardwoods have this characteristic and, in fact, have proved to be more fire

resistant in buildings than steel. However, all timbers do burn readily if

temperatures stay high enough and there is sufficient oxygen. Therefore,

timber buildings are not classified as fire resistant.

Timber has good thermal insulation, preventing materials not in contact with

the fire from heating up to extreme temperatures. When hot, timber does not

expand in length (unlike steel) and neither does it markedly lose strength.

Laminated timber structures glued with synthetic resins have similar fire

resistance to solid timber, although resistance will vary according to the type

of timbers and glues.



Stone

Stone blocks and slabs are usually satisfactory in fires, but overhanging

features and lintels are liable to fail. Free quartz (e.g. in granites) explodes

suddenly at 575°C and should not be present in any stone that is required to

be fire resistant. Sandstones behave better than granite, but in drying they

may shrink and crack, with 30–50% loss of strength.

Plastics

Although many plastics are made in fire-retardant grades, all are

combustible and some give off large quantities of toxic smoke. PVC

(polyvinyl chloride) melts at fairly low temperatures, and most

thermoplastics (plastics that can be heated and shaped) char above 400°C

and burn at 700–900°C.

Clay products

Most clay products perform well in fires, having been made at kiln

temperatures higher than most fires reach.

Brickwork failure is often caused by expansion of enclosed or adjoining

steel work.

Concrete

Ordinary Portland cement concrete disintegrates at 400–500°C. However,

how the concrete performs depends very much on the presence of

reinforcement and the type of aggregate it contains.

Metals

Metals used in building are non-combustible, but they lose strength when

heated. Aluminium, lead and zinc melt in building fire temperatures. As

previously mentioned, the expansion of the hot metal can cause problems.

Also, the high thermal conductivity of metals means that the temperature of

surfaces remote from a source of heat will approach the temperatures near

the fire, causing fires to spread.

Steel

Mild steel behaves in an interesting way when heated. Up to 250°C, it gains

strength, then gradually returns to normal strength by 400°C. After that, it

rapidly weakens so that, at 550°C (referred to as the critical temperature), it

begins to fail.

Generally, structural steelwork must be protected with fire-resistant

encasements, such as concrete or brickwork.

Glass

Although glass is non-combustible, it readily transmits heat and often

shatters unpredictably at an early stage in a fire. Toughened glass is not fire-

resistant.



Glass fibre and rockwool

Resin-bonded glass fibres are combustible. Glass fibres themselves melt at

about 600°C.

Fibrous cement

This material tends to shatter when heated, sometimes explosively. It does

not contribute to making a fire-resistant structure.

Paints

Generally, paint films are combustible and may help spread flame over

surfaces. However, as they are thin, they only contribute a small amount to

the fire load. When applied to combustible materials, certain paints can

reduce the spread of flames. They delay but never prevent the spread of

flame.

Compatibility of materials The large range of new materials on the market today, many of which are

chemically based, plus widespread pollution, has led to new chemical and

physical problems with materials. A material may break down many times

faster than normal in the presence of another particular substance. Problems

do not always show up until a product has been on the market for a number

of years. Incompatibility of building materials can be grouped roughly under

the following headings:

corrosion of metals

stains and discolouring effects

problems with surface finishes

chemical reaction between materials

shrinkage and expansion effects

structural differences

Corrosion of metals

Galvanic reactions: These occur between metals that have different levels

of electronegativity. This is often seen as corrosion of one metal or a

deposition of metal scale on the other metal. Offcuts or filings of metals left

around in moisture can cause rapid destruction of nearby metal building

components. Some common galvanic reactions are listed below.

Lead used with zinc or aluminium promotes corrosion. Therefore, metal roof-flashings need to be carefully chosen.

Steel screws or nails should not be used with aluminium or zinc roofing, unless they are zinc or cadmium coated.

Copper should not touch or drain onto zinc, aluminium, zincalume or galvanised materials.



Lead-based or graphite paints should not be used on aluminium.

Water–metal corrosion: Most iron or steel rusts on contact with air and

moisture. Protection is provided by galvanising or coating with zinc,

aluminium or PVC plastic.

Galvanised pipes: For water supplies these are reasonably durable where

water is hard or not acidic. But if water is low to moderately hard, corrosion

occurs quite rapidly at joints with brass or other copper alloys.

As heat speeds up corrosion, different metals should not be mixed in hot

water systems.

Copper and brass are permanently resistant to water.

Aluminium: This becomes encrusted in coastal atmospheres. Mortar, cement

or concrete pit the surface of aluminium if splashed on it.

Industrial atmospheres: These are usually acidic and corrode all metals.

Stains and discolouring effects

Copper: Water dripping off copper causes green stains.

Rust: Water running off exposed iron or steel will stain surrounding

surfaces.

Eucalypt timbers: When wet, many eucalypt timbers produce brown stains

on masonry.

Efflorescent salts: When these move through porous brick, stone, mortar or

concrete, they cause surface crusts called efflorescence.

Problems with surface finishes

When finishes won’t stick to the surface they are applied to, it is usually due

to the two being unsuitable for each other. The surface may either be too

smooth or it may be powdery or flaky; or there might be a chemical

incompatibility between the surface and the finish. This will be dealt with in

more detail in the unit on paints but a few special points are:

Many silicone sealants will not accept paint.

Acid-resisting grouts (for floor-tiles) cannot be satisfactorily cleaned from the tile surface.

Primers, undercoats, finish paints, lacquers, varnishes and stains should all be used according to manufacturers’

instructions as many are incompatible with certain materials.

Chemical reactions between materials

Salt: This is highly corrosive to iron and steel. Porous masonry and

ceramics (such as some stone, brick, terracotta and concrete) can be severely

affected by salt penetration.



Milk: Milk contains lactic acid, which is very destructive to concrete in

dairies and special surface treatment is needed.

Ammonia: Ammonia, present in some adhesives, can damage copper and

brass.

Lead and galvanised steel: These metals will corrode in wet conditions

when in contact with cement mortar or concrete.

Expansion and contraction

Differential rates of expansion and contraction can become problematic

when long lengths or large areas of a material occur, especially when

adjacent materials have different rates of expansion and contraction.

Expansion and contraction can result from temperature changes or from

chemical reactions in the material itself over time. For example chemical

changes in concrete over time results in shrinkage, whereas chemical

changes in clay brick work results in expansion with time. Building

designers must consider these impacts. Typically control is affected by the

incorporation of expansion joints at regular intervals and the structure.

Structural differences

Structural differences particularly strength and brittleness may determine

which materials can be used in close proximity and how they are joined.

Again building designers must consider and overcome these differences.

Testing of materials The testing of materials is carried out by the manufacturer or supplier before

delivery (e.g. stress testing of timber). Upon delivery, an inspection should

be carried out with respect to the quality and suitability for the construction

situation it is intended.

Concrete is one material which is tested on site (the slump test), and later

laboratory tested for compressive strength at 28 days. Materials such as

paints, adhesives, glass and the like have been developed and trialled under

strict laboratory controls and conform to Australian Standards.

You as the builder or supervisor of a building project, need to be

informed of all the information relating to products being used. Details

such as handling, storage, application, installation and warranties

should be kept in a product file and updated to provide ready access to

this information to avoid warranty problems associated with incorrect

handling and installation.

The most common test of building materials is the strength test to

destruction. Strength is a very important property of a building material,

even one which is in a nonloadbearing part of the building. Strength tests on



materials, apart from being relatively simple to carry out, also offer a guide

to other properties such as durability.

The strength of a ductile material such as steel, aluminium or plastic is

usually determined by applying a tensile load. A compression test is used

for brittle materials such as concrete, stone and brick because their tensile

strength is low and therefore harder to measure.

The method of testing and the dimensions of test pieces are laid down in the

appropriate standards produced by the Standards Association of Australia.

The size and shape of the test specimen are particularly important for brittle

materials because they influence the number of flaws that are likely to occur

in the test specimen.

For tests on concrete and timber it is necessary to specify moisture content

as this directly affects strength.

Concrete

Tests of factory made materials carried out by the manufacturer are usually

accepted by the user of the building material unless there is doubt about the

accuracy of the results. Since concrete is made on the building site or

brought from a ready-mix concrete plant, its testing becomes the

responsibility of the building contractor. This is therefore more frequently

tested than other materials. Concrete cylinders or cubes are normally tested

in a hydraulic press. A universal machine for tension, compression and

bending is also used.

Timber

Timber is far more variable in its properties. Cut timber may consist of a

variety of different species or there may appear appreciable variation

between pieces of timber due to knots, bark pockets, gum pockets or other

flaws.

When timber is used in domestic construction where it is not highly

stressed, a visual grading may be a sufficient means of testing the material.

Because of imperfections in individual pieces, stress grading is usually more

reliable than accurate testing of selected pieces. A stress grading machine

tests every individual piece of timber using a very fast and economical

method. The test is based on the relationship between the strength and the

deflection of timber. Each piece of timber is deflected at several points

along its length, and the deflection category marked by means of a spot of

dye. The timber is then classified visually by its colour markings.

Metals

The strength of metals is reduced if they are repeatedly loaded alternately in

tension and compression. This test is called repeated loading if the load is

applied several hundred or thousands of times, and fatigue loading if the

load is applied millions of times.



Other special tests for metals are for ductility and hardness. Ductility is

tested by bending a bar around a pin over a wide angle. Hardness is tested

by indentation with a diamond or a hardened steel ball. If the tensile strength

has been tested, then the hardness of the metal can be deduced.

The toughness of a metal can also be deduced from the tension test.

Toughness is defined as the energy required to break a material. The greater

the area contained under a stress-strain curve up to failure, the greater the

toughness of the material.

Handling and storage Planning for storage and handling of materials on site is an important job for

building staff. Many materials are easily damaged if due care is not taken in

handling, and some can deteriorate if exposed to moisture and direct

sunlight.

Materials should be stored in accordance with manufacturers’ instructions;

for example, stacked flat, off the ground, in a dry area or in a secure area for

flammable or toxic materials.

Transportation to the site and unloading arrangements need to be given

careful consideration and appropriate equipment must be organised.

When handling materials on site, safe working practices must be followed

and all OHS regulations implemented.

Generally, most materials are delivered to the building site and

responsibility begins with taking delivery, handling and storage of the goods

until they are required to be fixed. Many residential building sites have poor

facilities for the proper protection of some materials and this can result in

quality issues should they not be required to be built in soon after delivery

or if delays occur to the building program.

Individual materials must be stored and handled correctly to avoid

potentially hazardous, dangerous or even fatal situations from occurring on-

site. To achieve this, the individual builder must have a good general

knowledge of the properties of the materials being used, the correct methods

of handling and storage and be able to identify potentially hazardous

situations either on-site or in the transportation of materials to the site.

Some examples of storage and protection issues on building sites are:

bricks cannot be laid after heavy rain if they have become saturated

concrete block must be completely dry before they can be laid

windows (and reveals) will quickly deteriorate if left exposed to the elements for any period of time

cement will be rendered useless if allowed to get wet; sand will become saturated and will need to dry out before

useable.



reinforcement can develop surface corrosion if stored outside for too long before placement

timber engineered products can quickly deteriorate if left exposed.

particleboard and MDF products will break down under prolonged sun and rain exposure

most timbers particularly pine are not dimensionally stable if left exposed for any extended period. Wall frames and trusses

must be fixed in position as soon as possible after delivery

and the building enclosed to avoid any weathering of the

structure.

Most of these issues can be avoided with careful planning of deliveries to fit

the construction program and care in the providing of protection to goods

once delivered to the site and particularly when adverse weather conditions

are forecast. Wall frames could be scheduled to be delivered so they could

be craned straight onto the building platform and similarly trusses craned

directly onto the wall frames thus avoiding double handling and the

subsequent OHS issues of manhandling heavy materials.

Many building sites have poor access and require detailed planning of

materials handling. Today more than ever employers have a responsibility to

ensure they are employing safe practices on their site and the range of plant

available to move materials around a site has never been greater. The use of

small tower cranes on residential building sites was unheard of only a few

years ago but now is common on multi unit construction and even some

single residential projects especially those with limited access.

Considerations when ordering materials

Careful planning and scheduling of deliveries can very much influence the

success of your building project. Some considerations to be observed when

ordering materials are:

What is the lead time between ordering and delivery of the goods? (structural steel may take 6 to 8 weeks of more to be

ready for delivery)

Can the site accommodate the delivery of the full order? When ordering bricks for residential projects in particular, it

is best to receive the full order from one manufacturing batch

to avoid colour differences.

Is the site access adequate for the delivery method? Rugged sites may need a crane deployed to assist.

Are there set delivery days to the area of your project?

Are there delivery costs involved? Sometimes the delivery cost can exceed the cost of the goods.

Will there be workers on site to take delivery of the goods?

Are the goods required on the site now? Will workers be available to fix them in position?

Has the quantity been checked to avoid over and under supply?



What is being supplied in the order? Does the order for wall frames include temporary bracing?

Do we need to consult the Material Safety Data Sheet for the product? Should staff be trained in the handling of the

materials?

Is traffic control required to co-ordinate the delivery onto the site?

Obviously this work will be co-ordinated by the Construction Supervisor

and fits in with his/her role of providing supervision and co-ordination of

construction and safety on the building site. Wherever possible materials

should be handled and stored in accordance with the manufacturers

recommendations and always observing OHS practices including ‘duty of

care’ as set out in the legislation.

Security of materials should also be considered in the storage arrangements.

Pilfering is a constant threat on building sites and procedures must be

adopted to ensure protection is maintained.

One of the most important aspects of handling materials on-site is to ensure

that the materials are not damaged nor deteriorate in any way. Each type of

material has its own set of requirements with regard to safe handling, safe

storage and short term preservation. Any variance from such procedures can

ultimately result in an inferior product that reduces the overall quality and

can lead to operational failure in extreme cases.

Efficient work site practices depend on correct site placement of materials

once they are delivered to minimise them as a potential hazard and yet

maximise their efficient use when they are required for a particular job.

Bricks and concrete blocks Bricks are usually delivered on pallets to a site by truck. They are lifted off

by an attached crane and deposited at convenient locations around the site to

provide easy access by bricklayers. A popular alternative is to unload and

distribute pallets around the site using a truck mounted forklift. When

ordering bricks builders need to specify the required unloading option.

Where required, a labourer stacks the bricks safely, close to the working

area.

The moisture content of bricks can affect the strength of the construction in

the short term as normally the brick absorbs moisture from the mortar and

helps it to dry and harden. It may be necessary to cover bricks to minimise

the impact of rain prior to the laying of bricks.

Timber Generally, timber is delivered by truck and stacked by hand on-site. The

type of timber and its moisture content (how dry it is and whether it is kiln



dried or air dried) will determine where it will be stacked, what it is stacked

on and how it is covered.

Dried timber is usually wrapped in heavy duty polythene wrap by the timber

seller and left wrapped on site until ready for use. Timber may be stacked on

a pallet, or it may be placed on spaced wooden bearers that are laid on the

ground to prevent contact with the soil and the uptake of moisture from the

soil.

Timber is also susceptible to both wet and dry rot. Both conditions arise as a

result of fungus attack. Wet rot occurs when timber has been stored in

excessive or continuous damp conditions. Dry rot occurs when timber has

been stored in conditions where ventilation is inadequate.

Any localised softening of timber indicates that some form of decay has

developed.

Timber should always be protected from the elements. When exposed to

weather, timber will swell or shrink with moisture variations which will

cause cracks in the surface of the timber and further deep penetration of

moisture and decay.

Timber should not be stored on top of other materials. Eucalypt timbers in

particular, create a strong brown stain when wet by rain and will disfigure

any materials stored below.

Special precautions should be taken in termite prone areas to prevent insects

from entering the timber from the ground. All roots, stumps and timber off-

cuts should be removed from the site. The Australian cypress pine actually

possesses natural chemicals which make it particularly resistant to termite

attack.

Alternatively, fine steel mesh collar barriers can be placed in pipe holes in

floor slabs to prevent termite intrusion.

Fire is the greatest hazard to timber. All potential sources of ignition should

be removed from the site. Potential problems arising from smoking or faulty

electrical cabling should be minimised as part of the general management of

the site itself.

Concrete Storage and transportation of concrete is generally the concern of the

company that mixes and supplies the product. The responsibility of the

builder is to ensure that the site is ready to receive the concrete mix at the

time that it is ordered to arrive at the site. Any holdups on the site once the

concrete has arrived is the responsibility of the builder and this extends to

failure of the concrete to achieve its stated loading capacity as a result of

being held too long in the truck. The distance to the site and the concrete

requirements are usually taken into account by the company when they are

mixing the batch initially.



When concrete was mixed on the building site and then transported to its

final location by wheelbarrow, segregation of the concrete mix was not a

serious problem. With modern transportation methods however, which may

involve pumping the concrete or sending it by gravity down a chute over

long distances, it does become a problem.

Segregation is a separation of the constituents of concrete so that their

distribution ceases to be sufficiently uniform. It may be caused by a

differential settlement of the aggregates in which the larger particles, or the

heavier particles, travel faster down a pipe or slope, or settle faster in the

concrete when they reach their final destination. Another type of segregation

occurs particularly in wet mixes, results in the separation of the concrete

grout (i.e. the cement and the water) from the aggregate and its formation in

a layer on top of the concrete.

Cement should be stored in a well-aired, clean, dry place off the ground.

Wrapping the cement bags in plastic sheets will give extra protection.

Glass Whilst glass is extremely hard and resistant to many forms of chemical

attack, it does require careful treatment, especially on building sites. It is

usually delivered by trucks that have specially designed racks for carrying

glass. Often the windows are glazed by the window frame manufacturers

and transported as a whole unit.

The surface can be etched by cement wash, mortar or slurry if left and

allowed to dry, even after completion of the building. Removal of such

material must be by washing as soon as possible in order to avoid

scratching.

Torn protective covers on pre-glazed units often conceal such droppings

until stripped off. Replacement of the glass is the only way to overcome this

type of damage.

Similar damage can be caused by alkaline adhesives which are used to

attach suppliers’ names on warning signs to the glass.

Tolerances When ordering building materials for on-site fabrication the permitted

tolerance will often be determined by the ease and skill needed to cut and

join the material on-site. For example timber boards and planks are typically

trimmed on on-site. Steel framing is usually fabricated to precise

requirements using shop drawings offsite. Similarly frames and trusses are

fabricated to precise requirements using shop drawings offsite. Windows are

usually fabricated to standard sizes.



Of help is the Guide to Standards and Tolerances 20071 produced by the

Victorian Building Commission in collaboration with NSW Fair Trading,

the Tasmanian Government and the ACT Government.

The Guide is not a legal document and is not intended to replace the relevant

provisions of the Building Code of Australia or Australian Standards. The

Guide is intended to provide the reader with an understanding of the

tolerances that a building professional will consider in determining whether

a building element has been installed/constructed to an acceptable standard.

The Guide should be regarded as an advisory resource rather than a series of

prescriptive definitions.

The Guide helps home owners if building work is in dispute. It deals with

such topics as shrinkage around timber window frames, door frames, nail

popping in timber floors, paving through to footings and foundations.

All building work in Australia is covered by the Building Code of Australia

and many Australian Standards. These standards have been developed for

most building materials and detail tolerances, application, testing (if

applicable) and method of installation. These tolerances should be followed

and best industry practice adhered to.

When materials are manufactured, the specifications for the materials

indicate dimensional tolerance and/or loading tolerance for each product

type.

These tolerances are specified in the Australian Standards that cover those

types of materials and are usually stated in brochures or pamphlets

distributed by the manufacturer or supplier. The dimensional tolerances are

simply measurements which indicate the range distribution of the size of the

materials. For example a concrete block may be supplied as a 300 mm block

and yet the actual measurement may be 302 mm or 299 mm. The range

around which it can vary is the dimension tolerance indicated by the

supplier.

Similarly the dimensional tolerance must be allowed for when ordering

materials and when planning for their installation. This can be very

important for laying tiles for example, or allowing for the thickness of

particular wall cladding.

Similarly load or stress tolerance indicates the range in which the stated load

capacity of the material might operate. This must be taken into account

when using the material, so that a safety factor exists, which ensures that the

load can never be exceeded. This safety factor must be well outside the

tolerance values.

1 www.buildingcommission.com.au/resources/documents/S+T_GUIDE_07.pdf

http://www.buildingcommission.com.au/resources/documents/S+T_GUIDE_07.pdf



Activity 1 Get a copy of the Guide to Standards and Tolerances 2007 referred

to above and review required tolerances generally.



Quality standards and requirements

Materials permitted to be used in the construction of buildings are defined in

the BCA. This document applies throughout Australia and is available

through your local council or library.

In relation to this module, you will need access to Volumes 1 and 2 of

the BCA.

Before structures are erected, consent must first be gained by the

determining authority. Structures for which consent does not have to be

gained are prescribed in legislation. Essentially, if you can demonstrate to

the determining authority such as the local council that your proposed

structure will comply with the BCA, consent, in the form of a permit, should

be granted.

Remember that it is not the local council which establishes all criteria for

compliance. Officers employed by the local council, e.g. building surveyors,

merely enforce the relevant building legislation, of which the BCA is a

component. Therefore if designers and builders can satisfy the requirements

of the BCA, both in documentation and in practice, compliance with the

local council or other approving body should only be a formality.

Often, delays experienced by builders after lodging plans and associated

documentation for the purpose of being assessed for compliance and to gain

a building permit result from insufficient and/or inaccurate information

being submitted to demonstrate compliance with the BCA.

Read

Obtain a copy of the Building Code of Australia from your local Tafe

library. Read BCA volume 2 Section 1.

Volume 2 Section 1 of the BCA provides you with a good introduction into

who administers the document and the relevant legislative arrangements.

The interpretation section is similar to a glossary in that it provides a brief

explanation of terms used throughout the document.

Read

BCA - volume 2 Part 1.2 (Acceptance of Design and Construction).

This section demonstrates that the BCA is not purely prescriptive but is

performance based.

Part 1.3 indicates that structures are assessed only after first being classified

as a particular ‘class’ residential scale structure. The ‘class’ of a building



determines how it is assessed. As you will see most residential dwellings are

classified as being ‘class 1a’ buildings. For reference purposes Part 1.4

should also prove useful.

Materials and standards Suppliers of materials also have to comply with the relevant Codes and

Standards that apply to them. This is usually stated on the brochures or

wrapping material that accompanies the product. Timber is usually likewise

classified according to the relevant Australian Standards and the particular

classification is stated at the point of sale and on the invoice. It is also

labelled on all timber that has been graded. It is important that you are

familiar with the standards that relate to the material that is being used and

that you check at the point of sale to ensure that the material is appropriate

for the desired use.



Compliance and safety

Selecting materials according to specification and aesthetics is only one part

of the equation. The other most important factor to consider is whether the

material complies with all safety requirements and codes and regulations

that govern building in Australia.

The first and most important thing to consider is whether the material

complies with the Building Code of Australia (BCA), which is the overall

code that sets out compliance rules and calls up Australian Standards that

must be complied with when any material is produced or the circumstances

that govern its use.

These days, most materials that are sold have an attendant data safety sheet

or a sheet setting out the tests that have been performed on the materials to

ensure that the safe working design parameters have been clearly spelled out

to ensure that the material is only used within its tolerance limits.

If you are selecting materials for use in buildings then it is your job to

ensure that you have a good working knowledge of the tolerances associated

with those materials and have accessed the information sheets that detail the

safety requirements and the testing regime that has been undertaken.

In some cases the BCA details the way in which the material is able to be

used for example through the Australian Standard AS1684 for timber

framing. In other cases you are expected to go to the websites of particular

manufacturers and access the fixing and safety details for yourself.

For example details of steel roofing battens and the compliance

requirements may be accessed at:

www.roofingcentretas.com.au/cms/roofframing/steelroofbatten.php

http://www.roofingcentretas.com.au/cms/roofframing/steelroofbatten.php



Selecting building materials that consider the environment

When selecting building materials consider the relative environmental

impacts of various material choices.

Factors to consider include:

sources of raw materials;

the energy, greenhouse gases (CO2-e) emitted and the

environmental costs of processing, producing and

transporting the materials to site (embodied energy);

recycled content of materials and recyclability of materials;

life-cycle cost (total costs of production – needs consideration of durability and maintenance requirements);

ease of demolition, disassembly reuse and disposal;

selection of building materials that are low in VOCs

e.g. Dulux/Berger ‘Breathe Easy’ (light colours); refer www.rainforestinfo.org.au/good_wood/low_toxp.htm and

www.ea.gov.au/atmosphere/airtoxics/ solvent-based finishes,

adhesives, carpeting, particleboard and many other building

products; and

selection of building materials that are easily cleaned, durable and require minimal maintenance.

Consult also the following websites:

www.nphp.gov.au/enhealth/council/pubs/pdf/healthyhomes.pdf

www.health.gov.au/pubhlth/publicat/document/metadata/env_indoorair.htm

www.health.gov.au/pubhlth/publicat/document/env_indoorair.pdf

www.epa.gov/iaq/

www.epa.gov/iaq/pubs/insidest.html.

Use durable products and materials Manufacturing is very energy-intensive; therefore, a product that lasts

longer or requires less maintenance usually saves energy. Durable products

also contribute less to our solid waste problems.

Select more durable alternatives when evaluating materials, provided that

the materials are sourced from sustainable resources.

http://www.nphp.gov.au/enhealth/council/pubs/pdf/healthyhomes.pdfhttp://www.health.gov.au/pubhlth/publicat/document/metadata/env_indoorair.htmhttp://www.health.gov.au/pubhlth/publicat/document/env_indoorair.pdf



Choose low-maintenance building materials Consider life of materials and associated maintenance requirements before

selecting.

Where possible, select building materials that will require little maintenance

(painting, re-treatment, waterproofing) or whose maintenance will have

minimal environmental impact.

Minimise packaging waste Avoid excessive packaging such as plastic-wrapped fixtures or fasteners.

Advise your supplier that you are avoiding over-packaged products. Keep in

mind, however, that some products must be carefully packaged to prevent

damage.

Environmentally friendly materials Environmentally friendly buildings are resource efficient buildings which

are very energy efficient. They utilize construction materials wisely—

including recycled, renewable, and reused resources to the maximum extent

practical—are designed, constructed and commissioned to ensure they are

healthy for their occupants, are typically more comfortable and easier to live

with due to lower operating and owning costs, and are good for the planet.

How should the environmental impacts of different materials be measured?

A number of terms are used when measuring environmental aspects of

buildings and building materials. Some are:

GHG - greenhouse gas emissions. GHGs include carbon dioxide (CO2), methane (CH4), nitrous oxide (NO) and various fluorinated

gas emissions. The production of high levels of GHG during the

manufacturing and production of materials used in the building

industry use undesirable. There is an increasing trend to these

emissions to be measured and costed in the life-cycle cost of the

building. Divided into Scope 1 and Scope 2 emissions. If you want

to calculate your GHG usage use the online calculator at

www.carbonneutral.com.au

CO2e - CO2equivalent tonnes emitted into the atmosphere

Carbon footprint - total GHD emissions produced during manufacture construction and use. Buildings are responsible to 38%

of all human GHD emissions. Carbon neutral buildings are buildings

that are engineered to release no GHG gene

http://www.carbonneutral.com.au/



Embodied energy - the amount of energy required to manufacture a product including energy used in the extraction of raw materials,

transporting those materials, and processing them in to the final

product. The embodied energy of an item depends on its weight, the

materials from which it is made and the extent of manufacturing

required. As a guide the embodied energy per tonne of aluminium

and non-ferrous metals > plastics > iron and mild steel > glass >

paper > brick and concrete. However, a steel framed house has less

embodied energy than a concrete and brick house because it is much

lighter in weight.

Embodied water - the amount of water required to manufacture a product including water used in the extraction of raw materials,

transporting those materials, and processing them in to the final

product.

A number of rating systems are used to measure environmental aspects of

buildings. Some are:

WELS - Water Efficiency Labelling and Standards

2 - labels a range of products award

efficiency, allowing consumers to compare the

different products. The rating system has six

stars - the more the better. The labels also show

a water consumption flow figure. Toilets

appliances and taps are typically rated.

Energy stars - it is now mandatory in Australia that certain electrical appliances such as fridges, dryers, and washing

machines come with an energy rating. The energy ratings work on a

star system. The more stars, the more energy/gas/water efficient the

appliance is.

NABERS - the National Australian Built Environment Rating System

3 - is a national initiative managed by the NSW Office of

Environment and Heritage.

ABGR - Australian Building Greenhouse Rating is a rating system developed some years ago by NABERS

GBCA - the Green Building Council of Australia4 - provide a design only measure not a performance measure

The advantages of environmentally friendly materials

A number of government programs are aimed at certifying the

environmental credentials of buildings at either the design stage i.e. BASIX

in NSW or whenever sold.

2 www.waterrating.gov.au

3 www.nabers.com.au

4 www.gbca.org.au

http://www.waterrating.gov.au/http://www.nabers.com.au/http://www.gbca.org.au/



Also landlords now recognise that improved environmental performance

increases a buildings rental return particularly with commercial property.

Commercial tenants are able to gain kudos from the occupancy of an

environmentally sustainable building, and also cost savings in its operation

through more efficient design and plant.

GHD emissions associated with building construction come from

manufacturing transport and demolition activities. Strategies to reduce GH

chair emissions during construction include:

reduction in material quantity used

reduction in transportation costs by selecting materials from nearby manufacturers

recycle demolition waste rather than incinerate or use as landfill

Example - Concrete

Concrete is the most widely used material on earth apart from water, with

nearly three tons used annually for each man, woman, and child.

Worldwide. Cement manufacturing accounts for approximately 7% of CO2

emissions worldwide.5 Combustion accounts for approximately 40% and

calcination 60% of the total CO2 emissions from a cement manufacturing.

During the life of a concrete structure, the concrete carbonates and absorbs

the CO2 released by calcination during the cement manufacturing process.

Once concrete has returned to fine particles, full carbonation occurs, and all

the CO2 released by calcination is reabsorbed. A recent study indicates that

in countries with the most favourable recycling practices, it is realistic to

assume that approximately 86% of the concrete is carbonated after 100

years. During this time, the concrete will absorb approximately 57% of the

CO2 emitted during the original calcination. About 50% of the CO2 is

absorbed within a short time after concrete is crushed during recycling

operations.6

Example - Steel

Steelmaking generates greenhouse gas emissions, mainly carbon dioxide,

both directly when making iron and steel, and indirectly through the use of

electricity and gas. In Australia Bluescope steel produce 24 tonnes of CO2e

per tonne raw steel produced.7

5 www.wbcsd.org

6 Nordic Innovation Centre 2005 "03018 Carbon dioxide uptake in demolished and crushed

concrete" www.nordicinnovation.net

7 csereport2010.bluescopesteel.com/energy_greenhouse/our_greenhouse_performance.html accessed on

11/11/11

http://www.wbcsd.org/http://www.nordicinnovation.net/http://csereport2010.bluescopesteel.com/energy_greenhouse/our_greenhouse_performance.html



Embodied energy and emission tables

There are a number of sources for information on the environmental

performance of building materials. Part J of BCA volume 1 provides

excellent information on the energy efficiency of building elements and sets

up performance requirements for new buildings.

Embodied energy and emissions data also enables quick comparison

between building materials and systems. Refer to Fig 1 and Fig 2.The tables

indicate that the embodied energy and GHD emission for a timber framed

house superior to steel concrete and double brick housing. In part this is due

to the low emissions the timber over its life cycle.

ENERGY SOURCE OR

CONSUMER ITEM

EMBODIED

ENERGY

MJ/m2

EMISSIONS

FACTOR

(g/MJ)

GHG

EMISSION

(CO2e/

m2/yr)

House - Timber frame, floor &

cladding, concrete tile roof. Lowest

energy construction type

2,350 0.092 3.6

House - Timber or steel frame,

concrete floor, fibro-cement clad, steel

roof

3,400 0.092 5.2

House - Concrete block, steel roof

concrete floor.

4,100 0.092 6.3

House - Steel or timber frame, steel

roof, brick veneer clad, concrete floor

5,880 0.092 9.0

House - Double brick, tiled roof,

concrete floor

5,910 0.092 9.1

Figure 1: Estimated average embodied energy and emission8910

COMPONENT

kWh/ m2

indoor

floor area

Kg

CO2e/

m2

indoor

floor area

FLOOR

110 mm concrete slab on ground with foundations, or, suspended

concrete slab 172 mm 214 76

8 Glover, J., 2001. 'Which is Better? Steel, Concrete or Wood: A Comparison of

Assessments on Three Building Materials in the Housing Sector. '

www.boralgreen.net.au/researchch3/chap6.htm 9 Lawson, WR, 1996. 'Timber in Building Construction: Ecological Implications'

10 Rose, B.J., 2006, 'How to reduce greenhouse gas emissions, save money and maintain

quality of life' www.ghgenergycalc.com.au accessed on 11/11/11.

http://www.boralgreen.net.au/researchch3/chap6.htmhttp://www.ghgenergycalc.com.au/



COMPONENT

kWh/ m2

indoor

floor area

Kg

CO2e/

m2

indoor

floor area

Floor suspended slab 114 - 117 mm 208 68

Floor suspended timber on stumps 76 26

ROOF

Roof steel frame colorbond steel or tile 209 72

Roof timber frame colorbond steel or tile 143 47

WALLS

Walls double brick; s/b interior 312 103

Walls brick veneer timber frame 204 67

Walls timber frame fibro clad 61 20

Walls steel frame fibro clad 90 30

Walls Timber frame timber clad 68 23

Walls pre-cast concrete 264 88

Walls concrete block 160 53

OTHER , APPLICABLE TO ALL HOMES REGARDLESS

OF TYPE

Construction, admin, transport, other materials such as copper

pipes, glass, aluminium 406 144

Floor coverings assume approx. 50% ceramic tile 50%

polypropylene carpet 61 20

Fittings, fixed appliances built in $ bathroom, kitchen, w/robes 96 43

ADDITIONS kWh/ m2

area or m

length

Kg

CO2e/

m2 area

or m

length

Roofed open areas - alfresco / porch / verandah / carport 352 117

Garage single brick or cavity walls, concrete slab, steel or tile roof 675 219

Open Carport 352 117

Fence brick or metal (per metre length, assuming 1.5 m height) 186 61

Paving (brick or concrete) 96 32

Pool (concrete below ground) 534 198

Figure 2: Embodied energy and emissions per square metre of floor area,

residential house components11

The overall environmental impact of new building and community

development and the choices made when we either reuse or demolish

existing structures is very important.

11

Rose, B.J., 2009, GHG Energy Calc Background Paper

www.ghgenergycalc.com.au/freestuff/backgroundPaper.pdf accessed on 11/11/11

http://www.ghgenergycalc.com.au/freestuff/backgroundPaper.pdf



Use local materials Building designers and builders interested in sustainable practices have also

become familiar with local sources of construction materials, such as wood,

insulation, windows, concrete block, brick, gravel, etc. Using local materials

whenever possible reduces excess energy use from transporting materials

long distances and helps local economies by increasing jobs and keeping

cash-flows and tax revenues in your community.

The building products manufacturing industry is working quickly to provide

better means of informing consumers on environmental products through

standards and uniform assessment techniques.

Sustainability relies on making the right decisions with regard to

environment impacts and ecological costs. Decisions on selecting materials

go beyond short term economics and performance issues, although these

still remain part of the overall picture. There are a large number of criteria to

consider when making decisions on materials.

Products that reduce the quantity of material used Products meeting this criteria are included because of their resource

efficiency benefits. For example, plasterboard lining clips allow the

elimination of corner studs, engineered stair stringers reduce lumber waste,

pier foundation systems minimize concrete use, and concrete pigments can

turn concrete slabs into attractive finished floors, eliminating the need for

conventional finish flooring.

Recycled or salvaged products Whenever we can reuse a product instead of producing a new one from raw

materials—even if those raw materials are recycled—we save on resource

use and energy. Many salvaged materials used in buildings (bricks,

millwork, framing timber, plumbing fixtures, and period hardware) are sold

on a local or regional basis by salvage yards. Fewer salvaged materials are

marketed widely, and it is generally only local product directories that really

shine when it comes to finding salvaged materials.

Products with recycled content Many construction materials—such as cellulose and some mineral fibre

insulation, steel 'stud' framing, manufactured and structural wood products,

and sheathing for building exteriors—are now made from of recycled,

renewable, and reused materials in concentrations ranging from 20% to

nearly 100% in their overall content of recycled materials. Where



performance, durability, energy efficiency and cost trade-offs appear

reasonable, using such materials boosts overall energy efficiency, can

greatly benefit the environment, creates jobs and markets for such materials.

Recycled content is an important feature of many modern products. From an

environmental standpoint, post-consumer is preferable to post-industrial

recycled content, because post-consumer recycled materials are more likely

to be diverted from landfills. For most product categories, there is currently

no set standard for the percentage of recycled content required to qualify for

inclusion, but such standards will increasingly be developed in the future.

In some cases, products with recycled content are included with caveats

regarding where they should be used. Rubber flooring made from recycled

automobile tires is a good example—the caveat is that these products should

not be used in most fully enclosed indoor spaces due to off gassing

concerns.

In certain situations, from a life-cycle perspective, recycling has downsides.

For example, energy consumption or pollution may be a concern with some

collection programs or recycling processes. Also, closed-loop recycling is

generally preferable to down cycling, in which a lower-grade material is

produced.

Post-industrial recycling refers to the use of industrial by-products, as

distinguished from material that has been in consumer use. Iron-ore slag

used to make mineral wool insulation, fly ash used to make concrete, and

PVC scrap from pipe manufacture used to make shingles are examples of

post-industrial recycled materials. Usually excluded from this category is

the use of scrap within the manufacturing plant where it was generated—

material that would typically have gone back into the manufacturing process

anyway.

Certified wood products Third-party forest certification, based on standards developed by the

relevant government forestry body, is the best way to ensure that wood

products come from well-managed forests. Wood products must go through

a chain-of-custody certification process to carry such certification.

Increasingly, this is becoming a marketing ploy in Australia and will

become an important part of the building industry in this country.

Natural or minimally processed products Natural materials are less dependent on fossil fuels (though transportation

fuel and processing energy may be an issue). Bio-based natural materials are

biodegradable, often (but not always) low in volatile organic compounds

(VOC) emissions, and generally produced from short-rotation renewable

sources, such as agricultural crops. Examples include cork, linoleum, bio-



based form-release oils, natural paints, geotextile fabrics from coir and jute,

and such textile materials as organic cotton, wool, and sisal. Some mineral-

based natural materials, including tile and stone or reconstituted stone

products (depending on the binders used to reconstitute the material), can

also qualify for this criteria.

Alternatives to products made with environmentally hazardous components Some building products are considered because they are alternatives to

conventional products that are made from chemicals considered

problematic. A few product components can be singled out for avoidance

such as

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