the ecology of building materials

The Ecology of Building Materials


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The Ecology
of Building
Materials
Bjørn Berge
Translated from Norwegian by Filip Henley
With Howard Liddell

To my two girls,
Sofia Leiresol and Anna Fara

Architectural Press
OXFORD AUCKLAND BOSTON JOHANNESBURG MELBOURNE NEW DELHI


Architectural Press
An imprint of Butterworth-Heinemann
Linacre House, Jordan Hill, Oxford OX2 8DP
225 Wildwood Avenue, Woburn, MA 01801-2041
A division of Reed Educational and Professional Publishing Ltd
A member of the Reed Elsevier plc group
First published as Bygnings materialenes økologi © Universitetsforlaget AS 1992
First published in Great Britain 2000
Paperback edition 2001
English edition © Reed Educational and Professional Publishing Ltd 2000, 2001

All rights reserved. No part of this publication may be reproduced in
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England W1P 0LP. Applications for the copyright holder’s written
permission to reproduce any part of this publication should be addressed
to the publishers

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Printed and bound in Great Britain by The Bath Press, Bath


contents
Author’s foreword

vii

Foreword by Howard Liddell

ix

Preface

xi

Introduction

xiii

Important factors in the physics of
building materials

58

Section 2
The flower, iron and ocean
Raw materials and basic materials

5 Water and air
Water
Air

Section 1
Eddies and water-level markers
Environmental profiles and criteria for
assessment

65
65

66
69
69
74
81
92

1 Resources
Material resources
Energy resources

3
5
15

6 Minerals
Metallic minerals
Metals in building
Non-metallic minerals
Non-metallic minerals in building

2 Pollution
Types of pollution
Reduction of pollution in the
production stage
Reduction of pollution during
building use

25
28

7 Stone
Production of building stone

107
111

8 Loose materials
Loose materials in building
Sand and gravel as aggregate in
cement products
Earth as a building material
Brick and other fired clay products

117
119
121
121
128

9 Fossil oils
The basic materials
Plastics in building

141
144
147

10 Plants
Living plants

Timber
Grasses and other small plants
Building chemicals from plants
Cellulose

157
161
163
174
176
178

3 Local production and the
human ecological aspect
The production process, product
quality and the quality of work
Technology
Economy and efficiency

34
35
43
45
48
49

4 The chemical and physical
properties of building
materials
53

A small introduction to the chemistry
of building materials
54


vi

Contents

11 Materials of animal origin

179

12 Industrial by-products

183

Section 3
The construction of a sea-iron
flower
Building materials

13 Structural materials
Metal structures
Concrete structures
Stone structures
Structural brickwork
Earth structures
Plastic structures
Timber structures

Peat walls
The energy and material used by
different structural systems

189
191
192
200
203
209
221
222
237

14 Climatic materials
Thermal insulation materials
Warmth-reflecting materials
Moisture-regulating materials
Air-regulating materials
Snow as a climatic material
Metal-based materials
Materials based on non-metallic
minerals
Fired clay materials
Earth and sand as climatic materials
Bitumen-based materials
Plastic materials
Timber materials
Peat and grass materials
Materials based on animal products

Materials based on recycled textiles

243
244
247
248
253
255
258
259
270
272
275
276
278
287
297
305

15 Surface materials
Metal surface materials

307
310

238

Non-metallic surface materials
(pre-formed or applied)
Stone surface materials

Fired clay sheet materials
Earth surface materials
Plastic-based sheet materials
Living plant surfaces
Wall cladding with plants
Timber sheet materials
Straw and grass sheet materials
Soft floor coverings
Wallpapers

311
318
323
327
327
328
337
338
355
361
366

16 Building components
Windows and doors
Stairs

375
375
382

17 Fixings and connections
Mechanical fixings
Chemical binders

385
385
389

18 Paint, varnish, stain and
wax
The main ingredients of paint
Paints with mineral binders
Paints with organic binders

401
404
411
415

19 Impregnating agents, and
how to avoid them
Choosing quality material
Structural protection of exposed
components
Methods of impregnation
Oxidizing and exposure to the sun
Non-poisonous surface coats
Poisonous surface-coats or
impregnation
The least dangerous impregnating

substances

431
433
434
434

Index

443

429
430

435
438


author’s foreword
The Ecology of Building Materials came out originally in 1992 in Scandinavia. It has
now been revised and adapted for the English-speaking world.
The book is far-reaching in its subject matter: too far, maybe, for some readers.
There may well be the inevitable mistake or certain inaccuracies, if one dissects
the information. On discovery of any such mistakes, I would greatly appreciate
the corrected information being sent to me via the publishers, so any new editions will not repeat the same mistake. Any other comments, additions or ideas
are also very welcome. Many have helped me in preparing this new edition, first
and foremost my colleagues in our two Norwegian offices, Gaia Lista and Gaia
Oslo. Howard Liddell in Gaia Scotland has given a great deal of worthwhile and
necessary help in the preparation of the English edition.
I would also like to thank those who have read through the whole or part of

the manuscript and given me useful comments and corrections, among them:
Dag Roalkvam, Varis Bokalders, Jørn Siljeholm, Hans Granum, Arne Næss, Karl
Georg Høyer, Geir Flatabø, Peer Richard Neeb, Odd Øvereng and Tom Heldal.
And I would like to give an extra special thank you to the Translator, Filip
Henley. He has achieved a use of language that surpasses the Norwegian original.
Bjørn Berge
Lista, 1999


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foreword
The Ecology of Building Materials is a seminal contribution to the built environment survival kit. This important reference source has been confined to the
Nordic countries for too long and I am delighted to be involved in its introduction to the English-speaking readership. It is one of a select but growing group of
“Tools for Action” towards a sustainable construction industry.
There is a long tradition of books that have been influential catalysts towards
a change in attitudes to our human habitat. I believe, for example, that the 20th
century environmental movement was catapulted into centre stage by Rachel
Carson’s Silent Spring in 1966. It was, however, side-tracked into an obsession
with energy issues during the 70’s and 80’s. It is only since the Rio Summit in ’92
that the epidemic scale losses of natural bio-diversity, and the realisation of the
criticality of toxicity, in all its forms (including inappropriate and polluting forms
or fuel), have led to the re-discovery of our inappropriate relationship with our
planet.
I would like to think that this book will have an impact on the building industry as effective as that which Carson had on agriculture. We have all become
aware of the benefits of healthy eating even if we do not practice it as well as we
should, but how far has even the awareness of toxicity in buildings penetrated
the public’s conscious perception of the places in which they spend 90% of their
lives? Sick Building Syndrome is, however, a generalised catch-all in the mind of

the public at large – but it is already the case that they are expecting their environment to be free of risk and they are asking for the industry to sign on the dotted line to that effect. In such circumstances the precautionary principle appears
to be inevitable and specifying benign a pre-requisite. Therefore we need the
tools to do the job.
Understanding the life cycle of the materials we use every day has never been
more complicated, and therefore its ready interpretation was never more essential. As a major consumer of both primary and secondary resources and a major
producer of waste, the construction industry has been made well aware of its
responsibilities with regard to its enormous potential contribution to sustainable
development, and its part in the threat to all human existence if it fails to meet
the challenge. It is important therefore that it acquires the expertise now and not
at some unidentified time in the future to lessen its impact. This book is a significant source in the wide range needed for immediate and effective action.


x

Foreword

The clear fusion of well-researched fact with experienced opinion in this book
is certainly timely and indeed probably overdue, since it scores in much more
than the strictly numerical sense. A practising architect as well as a researcher
and author, Bjørn Berge presents a carefully considered view of a whole range of
key building materials – from the basis of his own underpinning, technical expertise. The Life Cycle Analysis research industry is replete with academic and
impenetrable LCA scoring systems, which run the gauntlet of seeking to establish mechanisms that will give equal valency to the infinitely measurable and the
essentially subjective and almost unmeasurable – usually ending in a three point
scale (good/neutral/bad or plus/zero/minus) that leaves specifiers as confused
as if they had not been given the information in the first place; this is especially
so when they see products scoring well, which instinctively they consider to be
very questionable. Selective or, worse, misinformation is now a significant problem as companies realise the sales pitch benefits of having an environmental profile – whilst the more cynical amongst them regard green issues merely as a marketing opportunity rather than what is becoming more and more clearly, at the
very least, a health and safety issue.
The great strength of this book is that it is written in a style which is neither
stodgy nor pulling its punches. Bjørn Berge simply states his view on building

materials and processes in a way which leaves the reader in no doubt as to what
their environment impact is.
I am reminded of the quotation by Richard Feynman: In technology it is not
enough to have good Public Relations because Nature will not be fooled.
It is particularly refreshing to have a reference source which sifts and evaluates
key components and is not then afraid to seek to influence our thinking and give
both opinion and guidance.
It has taken a while to convert this book into the English-speaking public
domain. Its Norwegian language precursor was published in 1992 and translation has been much more than a straightforward language exercise. Firstly Bjørn
Berge himself has updated and amended much of the original text, then Filip
Henley has done a tremendous piece of work in the primary translation from the
original Norwegian and I have then sought to contribute a bit of cultural translation, albeit Norway’s building industry – with its long timber tradition – is subject to all the same influences and trends as the rest of Europe, and hence the
need for the book in that context in the first instance.
Howard Liddell
Edinburgh 1999


preface
The building industry has not only become a major consumer of materials and
energy; it has also become a source of pollution, through the production of building materials and the use of pollutant substances. This book demonstrates that
alternatives to modern building materials are available and that today it is possible to produce building materials and select raw materials from an ecological
perspective.
At a time when environmental labelling is becoming increasingly popular and
the producers of building materials are urged to be more environmentally aware,
it is obviously important to be acquainted with these alternatives.
Important issues discussed in this book include:
• Can raw materials from non-renewable sources be replaced with raw materials from widely available or non-depletable sources?
• Can environmentally-friendly chemicals replace environmentally-damaging
ones?
• Can the make-up of building materials be altered so that their individual components can be re-used?

The following aspects will be illuminated in this book:
• Work: production methods of today and tomorrow
• Raw materials: deposits and their potential for reuse
• Energy: energy consumption in production and transportation
• Pollution: pollution in production, use and demolition.
With the aid of tables, each of the most important building materials in use in
Scandinavia will be given a characteristic environmental profile.
This book will be of special interest to environmentally-minded producers and
suppliers of building materials and to engineers, architects and building workers, but it may also be of use to readers who are interested in housing but who
lack specialist technical knowledge.


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introduction
‘We cannot cure illnesses, but we can help Nature cure herself’

Hippocrates

‘I object! I do not agree that the Earth and everything that exists on her shall be
defined by the law as man’s living environment. The Earth and all that is hers, is
a special being which is older, larger and stronger than us. Let us therefore give
her equal rights and write that down in the constitution and in all other laws that
will come . . .A new legal and moral status is needed where Nature herself can
veto us through her own delegates . . .One must constitute the right of all things
to be themselves; to be an equal with Nature, that is totally unarmed; do well out
of it in a human way and only in accordance with their own nature. This means
that one must never use a tree as a gallows, even if both its form and material fit
the purpose excellently. . .What practical consequences should a law like this

have? Before all economic considerations, this law would decide that nothing will
be destroyed or severely damaged, all outstanding natural forms, landscape characteristics and naturally linked areas shall remain untouched. No economic or
leisure concern shall be developed at the cost of nature, or worsen the living conditions of man and other beings. Everything that man wants to do in the future,
he must do at his own cost and with his own strength. As a result of this law we
may return to old methods of production or discover new ones which do not violate the law. The manufacturing society will crumble and multiply, the meaningless superfluity of similar products on the world market will give way to the local
market, independent of transcontinental connections.’
Ludvìk Vaculìk, Czech author, in his essay An alternative constitution

The Greek terms economy, ecology and ecosophy belong together:
Oikos House
Nomos Management
Logos Understanding
Sofos Wisdom
If we consider the world to be our common house, we can say that we have managed too much and understood too little. In Nature – the existential base of
humanity – the consequences of this are becoming clearer: forest death, desertification, marine pollution. These are things of which we are all aware. The growing incidence of mental problems among the populations of industrialized


xiv

Introduction

nations would indicate that we have not even understood the nature of ourselves
– that we, too, have become the victim of too much management.
Ecosophy expands the Kantian imperative ‘to see every person as a goal,
rather than a means’ to include other living beings. In this way, it defends the
value of Nature in itself, but is fully aware that it is impossible to escape the third
law of ecology: ‘All things are connected’ (Commoner, 1972).
The problem consists of establishing a perspective on Nature that has a genuine influence or, alternatively, establishing a general morality which is acceptable to all. The ecologist Aldo Leopold maintains: ‘A thing is right when it tends
to preserve the integrity, stability and beauty of the biotic community. It is wrong
when it tends otherwise.’

This represents an ethic for which, in ancient times, there was no need. Trond
Berg Eriksen (1990) describes the situation in antiquity:
‘In antiquity, commanding the forces of Nature and bringing discipline to
human nature were two sides of the same coin. In neither area did the
interveners need to fear that they would succeed completely. The power
of Nature was overwhelming. It took care of itself. Humans had to battle
to acquire the bare necessities. Nature’s order and equilibrium was
unshakeable. Man was, and considered himself, a parasite on an eternal
life system. The metropolis was a hard won corner, a fortified camp under
threat from earthquakes, storms, drought and wild animals. The metropolis did not pose a threat to Nature, but was itself an exposed form of
life. . . In such a perspective, technology was ethically neutral. Morality
comes into play only when one can cause damage, in relation to someone
or something that is weaker or equally strong. Therefore, the consequences of human actions for non-human objects lie beyond the horizon
of moral issues.’
Our ancestors’ morality was based on the axiom that man himself was the only
living being that could be harmed by human actions. Ethics focused on this;
ethics dealt with interpersonal relationships. At the same time this morality was
limited to the moment – only the immediate consequences of an action were of
significance. Long-term effects were of no interest and beyond all regulation.
Today, man’s position and influence is drastically changed. The way in which we
manage natural resources may have irremediable consequences for future generations of all life forms. Paradoxically, we still cling to antiquity’s anthropocentric moral philosophy, often mingled with some of the Enlightenment’s mottos of
man’s sovereign supremacy.
‘Four conditions to achieve a sustainable society’, according to L.P. Hedeberg
from the movement ‘The Natural Step’, are:


Introduction

xv

1.

Do not take more out of the crust of the Earth than can be replaced. This means that
we must almost totally stop all mining and use of fossil fuels. Materials that
we have extracted from beneath the Earth’s surface, for example metals, coal
and oil, are difficult for Nature to renew, except in a very small part. And that
takes time. On the surface the rubbish pile gets higher because we have not
followed this condition. And matter does not disappear – even if we reduce
it to very fine particles, by burning for example, it is only transformed into
molecular waste. Every single atom of a completely rusted car continues to
exist, and has to find a new home somewhere else. Everything just spreads,
nothing disappears.

2.

Do not use man-made materials which take a long time to decompose. Materials
that Nature can break down and change into nutrients belong to the natural
lifecycle. Man-made materials, which have never been a part of Nature, are
very difficult for Nature to break down. Certain synthetic materials such as
PCB, dioxines, DDT, freones and chloroparaffins will never be broken down
by Nature.

3.

Maintain the conditions for Nature to keep its production and its diversity. We
must stop impoverishing Nature through forest clearing, intensive fishing
and the expansion of cities and road systems. A great diversity of animals
and plants are a necessity for all life cycles and ecosystems, and even for our
own lives.

4.

Use resources efficiently and correctly – stop being wasteful. The resources that are
available must be divided efficiently and fairly.

The ecology of building materials
Is it realistic to imagine a technology that functions in line with holistic thoughts
while also providing humanity with an acceptable material standard of living?
This book is an attempt to suggest the possible role and potential of building
materials in such a perspective. And, in the same context, to illuminate the following aspects:
• Work. The methods used to produce each building component. How production takes place and can take place.
• Raw materials. Occurrence of material resources, their nature, distribution and
potential for re-use.
• Energy. The energy consumed when producing and transporting the materials, and their durability.


xvi

Introduction

• Pollution. Pollution during production, use and demolition, the chemical fingerprint of each different material.

How to use the book
This book is an attempt to present the possibilities for existing materials as well
as evaluating new materials. A number of partly abandoned material alternatives
have also been evaluated. In particular, we will look at vegetable products, with
traditional methods of preparation marked by former technological development. In their present state, these methods are often of little relevance, and the
reviews must therefore be regarded as experimental platforms on which to build.
Many factors relating to the materials discussed depend upon local conditions,
so the book is mainly based on the climatic and topographical conditions in

northern and central Europe. When considering the Earth as a whole, it will,
however, become quite clear how little the use of materials varies.
The materials dealt with are those that are generally used by bricklayers,
masons, carpenters and locksmiths. Under this category, all fixed components and
elements that form a building are included, with the exception of heating, ventilation and sanitary installations. Materials proving high environmental standards
are supplied with thorough presentations in the book while less attractive and
often conventional alternatives are given less attention.
It is my hope that The Ecology of Building Materials can function as a supplement
to other works on building. For this reason, only brief mention has been made of
some factors of a more professional nature. These include such matters as fire
protection and sound insulation, and other aspects which have no direct link
with ecological criteria.
The book is divided into three sections:
Section 1: Eddies and water-level markers. Environmental profiles and criteria for
assessment covers the tools which we will use to evaluate and select material on
the basis of production methods, the raw material situation and energy and pollution aspects. Tables show the different material alternatives available and information relating to their environmental profile. The information contained in
them derives from many different reliable European sources. They show quantifiable environmental effects and should be read in conjunction with the environment profiles in Sections 2 and 3. The final chapter gives an introduction to
the chemical and physical properties of building materials.
Section 2: The flower, the iron and the sea. Raw materials and basic materials presents the materials at our disposition. The term ‘raw materials’ denotes the materials as they are found in Nature, as one chemical compound or as a combination


Introduction

xvii

of several such compounds. They form the basis for the production of ‘basic
materials’ such as iron, cement, linseed oil and timber. These materials will form
building blocks in complete products. The section is divided into chapters which
present the different organic and mineral materials and discuss the ecological
consequences of the various ways of utilizing them.

Section 3: The construction of a sea-iron-flower. Building materials discusses
usage, such as roofing and insulation, and assesses the usability of the various
alternatives from an ecological perspective. Descriptions are given of the practical uses of the best alternatives. This section is divided into seven chapters:
• Structural materials which support and brace
• Climatic materials which regulate warmth, humidity and air movement
• Surface materials which protect and shield structures and climatic materials
from external and internal environments
• Other building elements: windows, doors and stairways
• Fixing and connections which join the different components
• Surface treatment which improves appearances and provides protection
• Impregnating agents and how to avoid them: the different impregnating substances and the alternatives.
The structural, climatic and surface materials covered in the first three chapters
represent 97–99 per cent of the materials used in building, and environmental
evaluations are given for each. The tables are based on available life span analyses and evaluations of building materials carried out in European research institutes (Fossdal, 1995; Kohler, 1994; Suter, 1993; Hansen, 1996; Weibel, 1995). In
addition to many conventional environmental evaluations, this book also discusses the human ecological aspects through questions such as the feasibility of
local production of building materials.
The evaluation tables are ordered so that each function group has a best and a
worst alternative for each particular aspect of the environment, then a summary.
The summarized evaluation means that priority is given to specific environmental aspects, which in turn relate to each particular situation. In such processes,
political, cultural and ethical aspects come into play in a strong way. In Africa,
the raw material question is usually given a high priority; in New Zealand and
Argentina, all of the factors that affect the ozone layer are strongly considered; in
Western Europe, the highest priority is likely to be acid rain. This book contains
the author’s own subjective views and the summarizing column should be taken
as a suggestion. The main aim of the book is to give the reader the opportunity
to quite objectively come to his or her own conclusions.


xviii

Introduction

It is also necessary to realize that all information is of the present moment. The
sciences that consider the different relationships in the natural environment are
relatively young, and in many cases just beginning. There are new aspects coming into the picture continuously, all of which affect the whole situation. One
example is chlorofluorocarbons (CFCs), which were not considered to be a problem in the 1970s before their effect on the ozone layer became known. The evaluations in the book are based on the before–after principle, the consequences of
using a material should be understood before it is used. Any uncertainty over
what a material actually is should not be to the material’s advantage.
It must be emphasized that the evaluation tables account for isolated materials and not constructions consisting of several elements as they occur in the
building. This may give a slightly distorted picture in certain cases, for example,
in the case of ceramic tiles and mortar or joint mastic which cannot be considered independently, or of plasterboard and fillers. In most cases, however, the
tables represent a thorough basis for comparisons between products at a fundamental level. It is also recommended to do further research into the sources of
this book. A comprehensive list of further reading is to be found at the end of
each of the three sections.

Life span evaluations of building materials
Many attempts have been made to establish evaluating methods to objectivise the environmental profile of building materials. These are based on a numbering and evaluating
system for the different environmental effects of a material during its life span. These evaluations take into account national and international limits for polluting substances in air,
earth and water, which are then added together. Methods include the EPS-EnviroAccounting Method (IVL, 1992), the Environmental Preference Method (Anink, 1996) and
the Ecoscarcity Method (Abbe, 1990).
In 1994 all three methods were tried in Swedish investigations on the floor materials
linoleum, vinyl and pine flooring (Tillman, 1994). One concentrated on the materials impact
on the external environment on the materials, and the different methods gave very different results. In all three methods the pine floor achieved the best result, while the linoleum
floor proved better than the vinyl in the EPS method but worse in the Ecoscarcity method.
In the Environmental Preference Method, the results for both floors were about the same.

Other guidelines for reading this book
Due to the arrangement of the groups of materials in this book, compound materials with components belonging to different substance groups will often be
encountered, such as woodwool-cement boards, made up of wood shavings and
cement. In such cases, the volume of each component will determine where that

material will be listed.


Introduction

xix

There will also be instances where a material has, for example, both structural
and climatic characteristics. The material will be included in both the main summaries and in the tables, but the main presentation will be found where it is felt
that this material best belongs.
A number of approaches and recipes for alternative solutions are described. If
no other sources are mentioned, these are the author’s own statements, and have
no judicial or economic bearing. In some cases, recipes with less well-documented characteristics are presented in order to give historical and factual depth.
Terms such as ‘artificial/synthetic’ and ‘natural’ materials are used. These are
in no way an assessment of quality. In both cases, the raw materials used were
originally natural. In artificial/synthetic materials, however, the whole material
or part of it has undergone a controlled chemical treatment, usually involving
high levels of heat. The extraction of iron from the ore is a chemical process,
while the oxidization or corrosion of iron by air is a natural process.
References
ABBE S et al, Methodik für Oekobilanzen auf de Basis
Ökologishen Optimirung, BUWAL Schriftenreihe
Umwelt Nr 133, Bern 1990
ANINK D et al, Handbook of sustainable building,
James & James, London 1996
COMMONER B, The Closing Circle, Jonathan Cape,
London 1972
ERIKSEN T B Briste eller bare, Universitetsforlaget,
Oslo 1990
FOSSDAL S Energi-og miljøregnskap for bygg, NBI,

Oslo 1995
HANSEN K et al, Miljøriktig prosjektering,
Miljøstyrelsen, Københaun 1996

IVL, The EPS Enviro-accounting method, IVL
Report B 1980:92
KOHLER N et al, Energi- und Stoffflussbilanzen von
Gebäuden während ihrer Lebensdauer, EPFLLESO/ifib Universität Karlsruhe, Bern 1994
LINDFORS et al, Nordic Manual on Product Life Cycle
Assessment – PLCA, Nordic Ministry,
Copenhagen 1994
SUTER P et al, Ökoinventare für Energisysteme, ETH,
Zürich 1993
TILLMAN A et al, Livscycelanalys av golvmaterial,
Byggforskningsrådet R:30, Stockholm 1994
WEOBEL T et al, Okoinventare und Wirkungsbilanzen
von Baumaterialen, ETH, Zührich 1995


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section

1

Eddies and water-level markers

Environmental profiles and criteria for assessment

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1 Resources

The earth’s resources are usually defined as being ‘renewable’ or ‘non-renewable’. The renewable resources are those that can be renewed or harvested regularly, such as timber for construction or linseed for linseed oil. These resources
are renewable as long as the right conditions for production are maintained.
Thinning out of the ozone layer is an example of how conditions for the majority of renewable resources can be drastically changed. All renewable resources
have photosynthesis in common. It has been estimated that man uses 40 per cent
of the earth’s photosynthetic activity (Brown, 1990).
Non-renewable resources are those that cannot be renewed through harvesting,
e.g. iron ore, or that renew themselves very slowly, e.g. crude oil. Many of these
are seriously limited – metals and oil are the most exploited, but in certain regions
materials such as sand and aggregates are also becoming rare. The approximate
sizes of different reserves of raw materials are given in Table 1.1, though there are
many different estimates. Everyone, however, is quite clear about the fact that
many of the most important resources will be exhausted in the near future.
Fresh water is a resource that cannot be described either as a renewable or nonrenewable resource. The total amount of water is constant if we see the globe as
a whole, but that does not present a drastic lack of water in many regions. This
is especially the case for pure water, which is not only necessary in food production but also essential in most industries. Water is often used in industry in secondary processes, e.g. as a cooling liquid, and thereafter is returned to nature,
polluted and with a lower oxygen content.

Usable and less usable resources
It is also normal to divide resources into ‘usable’ and ‘less-usable’. The crust of the earth
contains an infinite amount of ore. The problem of extracting ore is a question of economy, available technology, consequential effects on the landscape and environment and
energy consumption. Around 1900 it was estimated that to make extraction of copper a
viable process, there should be at least 3 per cent copper in the ore; by 1970 the level had

4

The Ecology of Building Materials

Table 1.1 Existing reserves of raw materials
Raw material

Statistical reserve (years)

Mineral
1.
Aggregate (sand, gravel)
2.
Arsenic
3.
Bauxite
4.
Boric salts
5.
Cadmium
6.
Chrome
7.
Clay, for fired products
8.
Copper
9.
Earth, stamped
10.
Gold

11.
Gypsum
12.
Iron
13.
Lead
14.
Lime
15.
Mineral salts
16.
Nickel
17.
Perlite
18.
Quartz
19.
Silica
20.
Stone
21.
Sulphur
22.
Tin
23.
Titanium
24.
Zinc

Very large

21
220
295
27
105
Very large
36
Very large
22
Very large
119
20
Very large
Very large
55
Very large
Very large
Very large
Very large
24
28
70
21

Fossil
25.
Carbon
26.
Natural gas
27.

Oil

390
60
40

(Source: Crawson 1992; World Resource Institute, 1992)

fallen to 0.6 per cent. Resources that have been uneconomical to extract in the past can
become a viable proposition; e.g. a more highly developed technology of stone extraction
would give this material a fresh start for use in construction. The sum of usable and less
usable resources are also called ‘raw material resources’, while the usable resources are
called ‘reserves of raw material’.
There are also cases where developed technology has a negative impact on the extraction of raw materials; e.g. technological development in the timber industry has made hilly
forests inaccessible. It is only by using a horse that one can get timber out of such a forest, but it is rarely the way of the modern timber industry, despite the fact that it causes
the least damage to the forest. In the same way, modern technology cannot cope with