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close this bookJournal of the Network of African Countries on Local Building Materials and Technologies - Volume 4, Number 1 (HABITAT, 1996, 42 p.)
View the document(introduction...)
View the documentThe aim of the Network and its Journal
View the documentSecond United Nations Conference on Human Settlements (Habitat II) -''The City Summit'', Istanbul, Turkey. 3-14 June 1996
View the documentHabitat II and the Construction Sector
View the documentConstruction Sector For Housing And Infrastructure Delivery - An Issue Paper Prepared For The Habitat II Conference**
View the documentHabitat II - A Breakthrough for Non-governmental Organizations in Committee II of the Conference
View the documentHabitat II - Shelter-Afrique Launches a Continental Housing Investment Programme and Seeks to Expand Membership
View the documentCost - effective Building Technologies - Technology Transfer, Dissemination and Extension: The Indian experience***
View the documentHabitat II - Conference closes as Habitat Agenda is Adopted, UNCHS to be Strengthened as Implementing Agency
View the documentEvents
View the documentPublications Review
View the documentBack cover

Construction Sector For Housing And Infrastructure Delivery - An Issue Paper Prepared For The Habitat II Conference**

** By Bans Der-Petrossian, Research and Development Division, UNCHS (Habitat). This paper was prepared and presented in a symposium on the same subject which was organized by the Settlement Infrastructure and Environment Programme (SIEP) of UNCHS (Habitat) and held as part of the Habitat II parallel events. The symposium was held in Istanbul on 5 June 1996.

I. Introduction

The construction sector plays a leading role in the improvement of socio-economic conditions and the built environment in every country. The sector is an important contributor to capital formation and the rate of activities in the sector is a major indicator of the health of the economy. The level of that contribution has been measured in several ways - notably in terms of gross domestic product (GDP) of the national economy and of capital assets or gross fixed capital formation (GFCF). In developing countries, major construction activities account for about 80 per cent of total capital assets and a single investment in construction sector yields continuous benefits over a long period.

Apart from economic benefits derived in the process of producing housing and infrastructure for the low-income population, the day-to-day functioning of low-income settlements, in itself, is of significance to national development. Unfortunately, there are insufficient data establishing a correlation between the economic performance of low-income settlements and levels of investment in shelter delivery. However, the little evidence available suggests that low-income settlements do not just provide basic shelter for people but, in addition, are economic domains with links to the national economic structure. For example, a single investment in the provision of an access road, linking the settlement to the market structure, in a rural area, leads to a significant increase in commodity output and, hence, improvements in national economic performance.

The Global Strategy for Shelter to the year 2000 adopted by the General Assembly of the United Nations in December 1988 calls for a shift in government's role from the provider of housing to an enabling one. The strategy also recognizes construction sector activities as one of the key inputs to the production and improvement of shelter and identifies several priority action areas in support of the indigenous construction sector including local production of building materials.

This issue paper is designed to provide a brief overview on the major constraints the sector faces and on challenges and opportunities which exist that could help low-income house builders to build their houses using low-cost/locally-produced materials. For the convenience of participants and for effective and fruitful deliberations, some key areas for consideration have been included in the last chapter of this paper.

II. The limitations of the construction sector

Despite the fact that many developing countries attach a great interest to the development of their construction industry, the sector is, generally not considered as a clearly identified industry. It is an industrial sector that is often ignored by major actors, e.g. economists, planners, administrators and others concerned with development issues. Consequently the sector is not planned in a holistic manner, but rather, operates with fragmented and often conflicting components resulting in wastage, inefficiency and inability to plan for total development. In fact, one of the main reasons for these inefficiencies is related to the multi-sectoral nature of the construction industry which requires sound planning and decision - making.

Apart from not planning the construction sector in an integrated manner, the major problems facing the sector are related to deficiencies in the specific inputs required. A review of the various ways and means of constructing low-income housing and infrastructure suggests that the unsatisfactory performance of the industry is due to several inter-related factors such as:

(a) An inadequate supply of durable and cost-effective building materials;

(b) Lack of technological know-how for the production of local building materials and for the construction of low-cost housing;

(c) Lack of adequate and favourable financing mechanisms for pre-financing low-income housing and infrastructure;

(d) Unfavourable regulatory mechanisms; and

(e) Lack of maintenance and upgrading strategies.

Furthermore, the construction industry in most developing countries has several deficiencies as far as its demand characteristics is concerned. Governments are usually the main clients of the construction industry, with a large demand for several categories of output by very limited financial resources to meet that demand. In the private sector, however, the bulk of the population is in the low-income or no-income category, and is not an effective market for the construction of shelter. In most developing countries, there are two basic approaches to construction of urban low-income shelter: public-sector construction programmes, and private-enterprise delivery of shelter. Almost invariably, the capacity of the public-sector option is very limited: it provides only marginal quantities of shelter, and the little that is produced is hardly ever accessible to the target group. On the contrary, the bulk of shelter construction for the low-income population results from the private formal and informal sectors which, in spite of facing various limitations, have made significant impact in shelter delivery over the past decades.

III. Basic resource inputs required by the construction sector

(a) Building materials

Building materials constitute the single largest input in the construction of housing and they sometimes account for about 70 to 80 per cent of the total value of a simple house. It is therefore important that building materials be made available in sufficient quantities and at affordable costs. However, building materials available on the market, in most developing countries are either prohibitively expensive and in scarce supply or of low quality. In some low-income settlements, the traditional building materials which have been popularly adopted over the decades are gradually declining in popularity. The fading popularity is probably due to the low quality of the traditional materials or to the relative attractiveness of "contemporary" building materials. Whatever the reason, this growing trend has had negative consequences on the low-income shelter-construction market.

In an attempt to overcome the problems of the shortage and high cost of building materials, many governments opted to establish large-scale factories to produce basic building materials. However, within a short period, many of these factories have been faced with numerous difficulties, arising primarily from the choice of imported technologies.

The absence of stable markets, exorbitant transportation costs and production interruptions resulting from the lack of spare parts and energy supply have often made production planning difficult, resulting in low-capacity utilization and scarcity of materials in the market.

The small-scale sector of the building-materials industry, however, has shown considerable potential in meeting the local demand, despite the fact that it often relies on traditional and outdated technologies. Lack of knowledge of innovative, energy-efficient and appropriate technologies based on local resources has been the biggest stumbling block in improving the productivity of this sector.

Even when low-cost building materials are attractive in terms of market price, there is still the problem of consumer biases against the products. For example, a preference for Portland cement, concrete blocks and corrugated steel roof-sheets, as against lime-pozzolana, stabilized soil blocks and natural fibre roofing tiles respectively, may not be based on cost considerations. Instead they stem from the lack of information on the technical properties of these innovative materials and the lack of awareness of the fact that costly materials can easily be replaced by innovative materials in building a simple house. The failure to use low-cost materials in government-sponsored housing construction projects is another serious constraint which limits the wide-scale adoption of these materials. Governments in developing countries are often the single largest clients of the construction industry; their efforts can easily popularize the use of these materials by private low-income house builders.

The above mentioned constraints in the building materials sector have the same negative effect on the provision of basic infrastructure as they have on housing supply. For instance, in rural areas and in urban squatter settlements, where public-sponsored programmes have provided water supply and sanitation systems, items such as sewers, septic tanks, latrine slabs and pavement tiles have mainly been procured from conventional supplyers, so that they have been also affected by the usual limitations of high cost and inadequate supply.

(b) Appropriate technologies

An important prerequisite for wide-scale application of appropriate building technologies is that the technologies involved are tested and widely known at local level. For example, appropriate technologies for the production of low-cost building materials have multiple advantages, including a reduction in the dependence on imported inputs, opportunities for developing substitute inputs from abundant indigenous resources and potentials for generating new and improved skills among local workforce. Appropriate technologies can also be useful for reducing the cost of construction output, which is particularly significant for the construction requirements of the poor.

In many countries, the main factor limiting the diffusion of a new technology is not so much related to setbacks in the transfer of technology at the international level but, rather, related to the inability of local institutions to translate successful research findings into commercial production. There are cases where technologies for production of low-cost materials have been developed by a local agency based on indigenous factor inputs, yet these findings have not been demonstrated on an extensive scale or replicated by any other agency.

The lack of requisite knowledge or techniques in the appropriate use of certain low-cost building materials in construction could also be an important factor limiting the wide-scale adoption of such materials. An indigenous building material, for example, can be sold at a low-cost on the market, however, where skills for appropriate use of it are deficient, the overall objective of low-cost construction will be defeated because of the excessive use of such materials. Where, skills are deficient, good-quality products could be wrongly applied in construction, thereby leading to unsafe and non-durable construction and, consequently, making a particular set of building materials, wrongly, unpopular.

(c) Financing construction

The construction industry is dependent on financing to purchase required inputs and to pay for labour costs. Shelter and infrastructure construction for the low-income population, even though termed "low-cost", is still dependent on financing, especially if conventional approaches are adopted. Any constraint in cash flow, therefore, could jeopardize a construction programme and, worse still, lead to cost escalations.

In most developing countries, existing public financial institutions do not fulfil the requirements for financial resources which are required for critical inputs in construction. The few available financing institutions have had little impact and the normal practice in private-sector low-income shelter construction is to depend on the builder's own finances which often are limited.

Financial resources are often more readily available in the private sector than in the public sector. Yet, in most developing countries, financing of public construction projects, which usually require large investments, are borne by public sources of finance. However, private-sector investment can be attracted with suitable conditions and interest rates. An example of this is the collection of tolls on highway projects as a means of paying back the investment.

(d) Regulatory measures, standards and specifications

Building acts, regulations and codes are the means by which authorities control construction activities for the purpose of ensuring safety and health in the built environment. Similarly, standards and specifications for building materials production and use, ensure stipulated quality of products used in construction. To a large extent, these regulatory procedures can determine the types of building materials, skills and construction techniques to be used in a given construction process. In this way, an opportunity is created to promote the use of appropriate building materials, so that the capacity of the shelter delivery can be enhanced. On the other hand. regulatory instruments can be formulated in a manner so as to prohibit the use of certain materials which are normally accessible to the low-income population and, thereby, limit the delivery of low-income shelter. For example, the use of soil in construction, probably, offers the best opportunity for most low-income settlements however, to build a safe and durable house in soil, requires some basic technical guidelines which can be provided through standards and specifications and permitted by building regulations.

The inadequacies of existing regulatory instruments have had negative effects on the provision of basic infrastructure to the low-income population in the same way as on shelter supply. Typically, existing public health acts and regulations, covering water supply, sanitation and solid-waste disposal, ignore actual practices in low-income settlements and do not offer any corrective devices to the unhealthy state of affairs and faulty trends in the minimal available infrastructure in low-income settlements. Rather, the regulations stipulate infrastructure standards which are far too costly for the target group and which, even if they were provided, could not be maintained with local resources and know-how.

(e) Maintenance and upgrading

The expected life-span of a building or infrastructure element presupposes that some basic regular maintenance will he provided during the service period of the facility. In normal practice, buildings and infrastructure also tend to be exposed to unexpected deterioration, thus requiring repair in addition to routine maintenance. Because of the low quality of construction in most low-income settlements, the concept of maintenance is even more relevant than in "high-cost construction". Maintenance is also crucial for low-income construction, because most low-income families cannot afford the replacement cost, should a building deteriorate to the point of failure.

A panel displayed in an exhibition during Habitat II Conference in Istanbul

Finally, given the low rate at which new dwellings and infrastructure are provided for the low-income population, a logical option is to ensure that the little that is already available is sustained in use to the utmost point of its service life. One reason why low-income settlements lack upgrading is that there is a disparity between the importance attached to new construction programmes vis-a-vis upgrading of existing settlements. Almost invariably, any governmental programme of investment in low-income shelter and infrastructure is linked to construction of entirely new facilities. Another reason for the lack of response to upgrading of existing low-income settlements is that it is a more challenging task than the straight forward delivery of new construction.

(f) Small contractors

Contractors are one of the key components of the construction sector, as they are directly responsible for the physical realization of the designs prepared in response to the client's needs and objectives. Small contractors in developing countries, even though can make great impact in the provision of housing and infrastructure, are often affected by several constraints which include:

(i) lack of technical and managerial expertise;

(ii) lack of adequate finance;

(iii) difficulty in obtaining essential resources, materials, equipment and skilled personnel; and

(iv) inadequate supervisory capabilities.

But these constraints could be easily removed, if adequate policies are in place and necessary support could be provided to them by governments, local and international communities. The ultimate goal which is to indigenize construction activities progressively and attain sustainable development and maintenance of built environment calls for strengthened small-scale contractors involvement in the sector, thus, improving quality of outputs and reducing costs.

IV. The role of communities, informal sector and women

Experience, over the past several years, has shown that involvement of communities, the informal sector and women in construction activities can considerably help in improving the human settlements conditions in most developing countries. Positive experiences in encouraging local initiatives by community-based groups and informal sector have demonstrated the many advantages and social opportunities such an approach can provide to marginalized groups. By mobilizing the skills and financial resources of the community, generating income and employment opportunities, and by giving the opportunity of participating in wider decision-making, this approach has proved to be a useful and effective measure to improve the housing delivery systems in many developing countries.

There are many successful examples of women's cooperatives in the manufacture of building materials. For example, block making operations in Ghana are largely managed by women, and in Zimbabwe the rural brick making industry is dominated by women. Similary in Kenya, the roofing tiles of a large public housing project were produced by women groups. Awareness-raising programmes and training opportunities set up to increase the number of women entering the construction industry have been found to be successful in a number of countries.

V. Health hazards of building materials

A variety of building materials contribute to different aspects of health hazards. Such materials include asbestos, solvents (e.g. toluene, xylene and dichloromethane), insecticides and fungicides (e.g. arsenic, dieldrin, lindane, pentachlorophenol), toxic metals (cadmium chromium and lead), and radon exhaled from building materials containing radium. Risks to health usually result from exposure to harmful environmental conditions in the extraction, production and use of certain building materials, and the disposal of related wastes. The harmful interaction of these factors and the human organisms occurs either by absorption through the skin, by intake into the digestive track via the mouth, or by inhalation into lungs. The results of the interactions can be harmful to human health in a variety of ways, including: respiratory diseases such as asthma, heart diseases, cancer, brain damage or poisoning. The effects of the hazards may be slow, cumulative, irreversible, and complicated by non occupational factors such as smoking.

Some of the health hazards associated with building materials and the built-environment are well documented and programmes to reduce them are in place. Others are the subject of current and future research, consequently remedial measures are not yet in place. There is also low public awareness of the health hazards, and additionally many decision-makers are not fully informed or aware of the health implications of building materials. Inadequate information greatly inhibits the ability of the construction industry and other stakeholders in effectively responding to the challenge of controlling the health hazards associated with building materials. Therefore, there is an urgent need to design programmes at industry, national and international levels to raise the understanding of the health implications of building materials on a continuing basis.

Given the fact that environmental sustainability and risks to human health rank among the most important areas of social concern today, and given the variety of hazards which need to be addressed, and the different groups exposed to hazards, a range of control strategies need to be established and implemented.

VI. Environmentally-sound construction

The construction industry, as a major consumer of worlds' natural resources and a potential polluter of the environment, is being closely scrutinized by the international community and many governments. With rapid urbanization and population growth, developing countries, are bound to use more energy intensive materials such as cement, steel, glass etc. than they were using 2 to 3 decades ago. Similarly, due to expansion of the construction sector in many countries, tropical hardwood, metallic and non-metallic minerals and non-renewable energy resources are used extensively, all of which are indications of certain threats to the capacity of natural resources, depletion of which will jeopardize the survival of future generation. The need, therefore, to introduce more sustainable construction practice is taking new urgency in the overall development context of human settlements.

Energy is one of the main inputs to the construction and, particularly, in the building materials production processes. Of the energy used in the production of building materials, a high proportion is in the production of a small number of key materials such as steel, cement, bricks, concrete elements, aluminium and glass. Similarly, different types of construction systems (designs) can result in considerable differences in the total embodied energy requirements in a complete house as indicated in the table below.

Comparative energy requirements for three single-storey houses in Argentina

House type

Embodied energy requirement (MJ/m2)

House made primarily with manufactured materials (hollow-brick walls, concrete frame and roof)


House made partly with manufactured materials (clay-brick walls, concrete frame, steel-sheet roof)


House built primarily with local materials (adobe walls, timber frame, steel-sheet roof)


Source: UNCHS (Habitat), 1991

The process of socio-economic development through increased construction activities and protection of the environment are not separate challenges. The sustainability of development cannot be ensured in a climate where growth plans consistently fail to safeguard the environment and arrest the degradation of the natural-resource base and the ecosystem as a whole. It is for this reason that Agenda 21. adopted by the United Nations Conference on Environment and Development (UNCED), underscores the importance of the sustainable construction industry activities as a major contributor to the sustainable human settlements development.

While increased awareness and knowledge of the implications of resource depletion and environmental degradation caused by the construction industry activities have resulted in taking some action in the industrialized countries, the developing countries, particularly in sub-Saharan Africa, have made very little progress in arresting this situation. Their position is even more desperate given that many of them are faced with fragile environments involving aridity, decertification, flood occurrences and other types of natural hazards.

VII. Proposed points for discussion

In the light of the above mentioned issues, participants may wish to consider the following points for discussion:

(i) Which are the important public policy areas that affect the performance of the construction and building materials industries?

(ii) To what extent policies in other sectors can affect the construction industries?

(iii) How can appropriate and new technologies be harnessed, transferred and adopted so as to improve the productivity of the construction sector?

(iv) What measures should governments, private sector and communities take to improve financing of construction sector?

(v) What measures should governments and local authorities take to revise the existing building regulations to encourage the use of low-cost/appropriate building materials in low-cost construction?

(vi) What strategies should be adopted to create a culture for maintenance of buildings and infrastructures?

(vii) How can international cooperation support the communities, informal groups and women to be more involved in shelter and infrastructure delivery?

(viii) In what ways governments and international community can support local initiatives to promote energy-efficient and low polluting building materials production technologies?

The Secretary-General of the Habitat II Conference, Dr. Wally N'Dow visited a model brick production site during the Conference. Photo: Amrik Kalsi, UNCHS (Habitat)