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ClB TG 16, Sustainable Construction, Tampa, Florida, USA, November 6-9 , 1994. THE ENVIRONMENT AL IMPACT OF BUILDING MATERIALS CHOICE FOR LOW INCOME HOUSING IN KENY A G . Chris Macoloo Department of Geography University of Nairobi P. O. Box 30197, Nairobi, KENYA INTRODUCTION The construction industry is an important aspect of economic development, and indeed an indicator of the health status of an economy. The intensification of human economic activities and the high rates of population growth in developing countries have put fhe construction sector under the microscope because of the raw materials required to sustain this sector. The over- exploitation and mismanagement ofthe raw materials threaten the sustainability of the building materials industry all over the world. In Kenya, the issue of sustainability of the construction sector is particularly crucial because Kenya has one of the fastest growing populations in the world (over 3% per annum) and an equally fast urbanisation rate (7% - 10% per annum). This is compounded by the fact that only 17% of the country's land mass is agiiculturally productive where food and cash crops compete with the sources of organic and inorganic construction materials. Kenya's urban housing policy encourages the use of the so-ca lied permanent building materials (portland cement, galvanised corrugated iron sheets, sawn timber and concrete or coral blocks), but discourages the use of others. This paper discusses how a rigid and inappropriate housing policy can predetermine the utilisation of specific construction materials which in turn impacts upon environmental management and conservation. It is argued that unless sound environmental conservation policies are incorporated into the exploitation of building materials (both organic and non-organic), Kenya's construction industry, particularly the residential housing sub-sector, will in the long run be unnecessarily expensive and unsustainable. KENYA'S URBAN HOUSlNG POLICY In many respects, Kenya's current urban housing policy is primarily a product ofthe colonial urbanisation and housing policies. During the period preceding the Second World War, the British colonial govemment aimed at controlling the African urban population to 'manageable' levels. Hence the African urban population was viewed as transitory because, it was argued, it would eventually return to the rural areas after a brief urban sojoum. This view was propped up by the fact that the majority of the urban centres in Kenya were colonial creations. Furthermore, the low wages paid to the African urban labour force were intended to discourage them from living with their whole families in towns. In Nairobi, for example, in 1935 the ratio of men to women was 6: I (Macoloo, 1989). For this reason, employers provided accommodation suitable only for single men. The housing situation was aggrevated by the intolerance of the administration to any buildings not constructed of permanent materials. Demolitions of irregular settlements, therefore, became the order of the day in many urban 847

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ClB TG 16, Sustainable Construction, Tampa, Florida, USA, November 6-9, 1994.

THE ENVIRONMENT AL IMPACT OF BUILDING MATERIALS CHOICE FOR LOW INCOME HOUSING IN KENY A

G . Chris Macoloo Department of Geography University of Nairobi P. O. Box 30197, Nairobi, KENYA

INTRODUCTION

The construction industry is an important aspect of economic development, and indeed an indicator of the health status of an economy. The intensification of human economic activities and the high rates of population growth in developing countries have put fhe construction sector under the microscope because of the raw materials required to sustain this sector. The over­exploitation and mismanagement ofthe raw materials threaten the sustainability of the building materials industry all over the world. In Kenya, the issue of sustainability of the construction sector is particularly crucial because Kenya has one of the fastest growing populations in the world (over 3% per annum) and an equally fast urbanisation rate (7% - 10% per annum). This is compounded by the fact that only 17% of the country's land mass is agiiculturally productive where food and cash crops compete with the sources of organic and inorganic construction materials. Kenya's urban housing policy encourages the use of the so-ca lied permanent building materials (portland cement, galvanised corrugated iron sheets, sawn timber and concrete or coral blocks), but discourages the use of others. This paper discusses how a rigid and inappropriate housing policy can predetermine the utilisation of specific construction materials which in turn impacts upon environmental management and conservation. It is argued that unless sound environmental conservation policies are incorporated into the exploitation of building materials (both organic and non-organic), Kenya's construction industry, particularly the residential housing sub-sector, will in the long run be unnecessarily expensive and unsustainable.

KENYA'S URBAN HOUSlNG POLICY

In many respects, Kenya's current urban housing policy is primarily a product ofthe colonial urbanisation and housing policies. During the period preceding the Second World War, the British colonial govemment aimed at controlling the African urban population to 'manageable' levels. Hence the African urban population was viewed as transitory because, it was argued, it would eventually return to the rural areas after a brief urban sojoum. This view was propped up by the fact that the majority of the urban centres in Kenya were colonial creations. Furthermore, the low wages paid to the African urban labour force were intended to discourage them from living with their whole families in towns. In Nairobi, for example, in 1935 the ratio of men to women was 6: I (Macoloo, 1989). For this reason, employers provided accommodation suitable only for single men. The housing situation was aggrevated by the intolerance of the administration to any buildings not constructed of permanent materials. Demolitions of irregular settlements, therefore, became the order of the day in many urban

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centres in Kenya. At the time of independence in 1963 the new government was faced with a situation

characterised by a sudden rise in the rate of urban growth. This was due to the relaxation of previous restrietions on African urbanisation, similar to what occurred in Zimbabwe over a decade aga (Drakakis-Smith, 1986) and recently in Namibia (Macoloo, 1990). The inherited housing situation in Kenya was bleak because at independence 70% of the African households occupied single rooms, and over one-half of such households consisted of three or more members (Kenya, 1966).

In order to tackle this ' urban housing crisis' characterised by sharing of accomodation by households, the government formulated a policy which emphasised the production of housing for low income people. The government specifically emphasised the application ofthe concept of 'aided self help' in providing housing for the urban poor. Hence site and service and settlement upgrading became the official programmes of action by the state in providing low income people with shelter. This first post-colonial housing. policy document also recognised the fact that in order to ensure a sustained construction of a large number of houses at reasonable costs, it was imperative to conduct research on building techniques and alternative materials.

To be implemented concurrently with this research activity was the suggestion to revise the building by-Iaws and planning regulations which were viewed by the majority as unnecessarily stringent. However, in the enthusiasm to provide some form of legitimacy to the new administration (through being seen to provide better services than the colonial government did), the housing policy makers dragged their feet in revising the building codes and by-Iaws. In fact, it was govemment policy that an urban dwelling must have at least two habitable rooms, a kitchen and a toilet. Policy statements of good intention were, therefore, not effectively implemented to provide the expected policy outcomes. One important manifestation of the lack of seriousness with which housing provision is viewed by decision-makers is the decline in housing investment as a share ofthe GDP. This share declined from 4.6% in 1980 to 3.4% in 1984 (Macoloo, 1989). And in most cases, only 0.5% of the budget allocated for housing provision is actually used, but primarily for producing high cost housing. This has meant that the performance of the housing sector, particularly the low income sub-sector, is continually below par. By 1988 the housing units needed in Kenya's urban areas were 60,700, a figure expected to rise to 122,060 by the year 2000 and to 173,200 by the year 20 I 0 (Kenya, 1990). These projections have serious land, finacial and environmental implications.

In an attempt to meet the housing requirements up to the year 2010, the government has formulated some objectives it hopes to help it achieve this goal. These objectives are, in/er alia, that:

(i) the govemment will only perform those functions that the private sector cannot do sufficiently such as land use planning, infrasatructure provision and the provision of housing for the urban poor (which is planned to take 70% of the resources earmarked for housing);

(ii) the costs of providing housing stock be recovered fully in order to avoid unnecessary subsidies; and

(iii) settlement upgrading coupled with minimum displacement and incorporation of income-generating activities be continued .

In summary, therefore, the Kenyan government is committed to the policy of urban home ownership, and as a result very little has been done to encourage the construction of rental units during the last two decades. Different income groups are expected to achieve this objective of

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horne ownership in different ways. For the low income groups, site and se:.ice and settlement upgrading have been the main programmes of action . The higher income groups, on the other hand, are expected to utilise the mortagage facilities offered by the financial institutions and the building societies. The involvement of the state in housing provision immmediately after independence was occasioned by the realisation that the private sec tor tends to price out the urban poor from effective participation in the housing marke!. With the re-introduction, in the 1990s, of policies that encourage the intensification ofthe private sector involvement in housing provision, it is likely that the housing problem will continue to bite. This will be compounded by the rigid building by-Iaws, codes and standards that have continued to ignore the economic realities of the majority of the urban residents. Arevision of some of the planning regulations and building by-Iaws has been done, but the government is yet to approve and implement them.

In the next section, we examine the implementation of a low income housing project in Kenya, and how this influenGed the choice of materials for house construction and upgrading.

THE IMPLEMENTATION OF PROGRESSIVE HOUSING DEVELOPMENT POLICY IN KENYA

As a result of the research findings in Latin America in the 1960s, attitudes towards irregular (squatter) settlements began to change. It was reported that squatter property owners use all the resources at their disposal to upgrade their houses gradually by replacing the temporary materials as weil as installing services such as electricity and water in their buildings. These settlements began to be viewed not as static entities but more appropriately as dynamic organisms that exhibit positive change over time. They were no longer to be considered as centres of political, social , and economic disorganisation but as any other neighbourhood that is interested in gentrification and economic productivity.

Despite the spatial and temporal specificity of these research findings, they strongly influenced World Bank thinking on housing policies and programmes in developing countries. Consequently, the World Bank advised these countries against constructing conventional houses and the demolition of irregular settlements. This led to the forrnulation of housing policies which are supportive of the so-called self help phenomena wh ich harnesses the latent resources of the urban poor for shelter provision. This is the policy of aided self help or progressive housing development whose two main programmes of action are site and service and settlement upgrading projects. Although there are variants of this policy, the site and service component involves the allocation of serviced land to low income people 10 develop over time under the technical supervision of and occasional loans from the state. Settlement upgrading, on the other hand, involves progressive improvement and regularisation of existing settlements through the combined effort of the state and the beneficiaries with minimal displacement of their original inhabitants.

This policy received massive financial support from the World Bank and became incorporated into mainstream urban planning as the chief method of low income housing provision in developing countries . Estimates show that between 1972 and \981 the World Bank provided loans totalling over US $2 billion to support this policy in 35 countries. During the same period, Eastern and Central Africa received US $153 million, 43% of which was loaned to Kenya to implement this housing policy.

The World Bank and the United States Agency for International Development (USAID) pioneered the financing of this policy in Kenya (Macoloo, 1994). The USAID financed the construction of 3,000 expandable units at lJmoja in Nairobi in 1973 and later financed similar projects in twelve other municipalities in Kenya during the last half of the 1970s (USAID, 1979). The World Bank, on the other hand, negotiated the implemetation of the Dandora site and service project in Nairobi during the 1973/1974 period. The Bank provided 54 .2% of the

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estimated cost of the project wh ich produced 6,000 serviced plots for low income people. The Dandora project is usually referred to as World Bank's first urban project in Kenya in order to distinguish it from the Bank's second urban project which was implemented in Nairobi, Mombasa and Kisumu between 1978 and the early 1980s. The second urban project (SUP) incorporated, for the first time in the history of Kenya's urban housing policy evolution, the concept of upgrading and it cost about US $69.4 million of which the Bank provided 72% (World Bank, 1978).

The World Bank's second urban project in Kenya had as its major objectives the increase of the supply of serviced plots, upgrading of unserviced settlements, promotion of self help housing construction techniques, and the encouragement of the use of local building materials. The project provided 9,000 serviced plots in Nairobi, 1,700 in Mombasa and 500 in Kisumu, in addition to upgrading 1,200 units in Kisumu and 1,000 in Mombasa. The concern of this paper is with the Mombasa project, to which we now turn .

The Mombasa Project Mombasa is Kenya's second largest city with an estimated population of over 600,000. tt

is located on the Indian Ocean coast, and its history spanned over 750 years before the dawn of British colonisation of Kenya. It had absorbed various waves of migrations involving the Arabs, the Asians and the Portuguese. It is, therefore, an 'indigenous' town whose land use patterns and characteristics differ from those of other Kenyan towns which were created from scratch by the British. Mombasa has for a long time had a distinct housing sub-market for low income urban workers. This consisted mainly of irregular settlements where the dominant house type was the swahili house. The swahili housing form is characterised by a rectangular design with a common entrance and between four to eight independent rooms leading off from a central corridor. the construction of the swahili house had an identifiable building materials sector. The houses were constructed entirely of borili (mangrove poles), makonge (sisal poles), makuli (coconut palm thatch) and udongo (earth). The design of the house allowed the owner to rapidly construct a rudimentary but liveable shelter wh ich could be improved to higher standards when time and finances allowed. Before the implementation of the World Bank project, the swahili house was the dominant type of shelter in Mombasa's low income settlements.

One of the settlements in Mombasa which benefited from the World Bank's SUP was Chaani. This was an irregular settlement on Mombasa's West Mainland, located over 6 km from the town centre. lt had developed gradually as a low income settlement with predominantly swahili houses. Prior to the commencement of upgrading in 1979 there were over 1,000 dwellings constructed at the density rate of 25 structures per hectare. The houses were constructed of temporary indigenous materials and the basic services were lacking. By 1979 only 5% of all the buildings in Chaani were in good structural condition; 40% needed repair; and 55% were beyond repair (Waweru and Associates, 1976). Because of these unenviable characteristics, Chaani was an obvious choice for upgrading. According to the World Bank programme, the existing houses were upgraded to a more acceptable level and services and infrastructure such as roads, water, sewerage, aod health clinics were to be provided.

During the upgrading process, the house owners were not allowed to use any material apart from permanent ones. These so-called permanent materials included concrete blocks, tiles, corrugated iron sheets, sawn timber etc. Because of the poverty of most of the beneficiaries of the project (at this time over 50% of the Chaani residents earned less than KSh. 400 per month wh ich was about one-quarter of the official minimum wage), there was a mixture of materials that were used in the settlement both for construction as weil as for upgrading.

In the next section, we examine the impact on the environment (actual and predicted) of

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using some of these materials, and the extent to wh ich the use of these materials could be sustained.

BUILDING MATERlALS CHOICE AND ENVIRONMENTAL IMPACT

The basic function of a dwelling is to provide shelter from natural and man-made hazards. Hence the choiee of building materials is of paramount importanee. The use of naturally occurring materials in the construction process is an old practice reflecting both the climatic diversity and the spatial di stribution of resouree endowments. Because of technological advaneements, house construction the world over currently reflects less the availability of materials and their climatic suitability, but more the affordability of materials and the changing nature of building technology.

In developing countries, the majority of which lie within the tropics, the chief building materials have been earth, wooden poles, bamboo and thatch. With the colonisation of these countries by govemments from temperate lands, different building materials were introduced and these included port land cement, concrete, steel beams, glass and galvanised corrugated iron sheets. The adoption of these materials began to take a new dimension and was increasingly equated with modemisation, and these materials were the only ones whose use was permitted in cities. Because of the high foreign exchange content of these materials they proved too expensive for the majority of the urban dwellers who had no option but to continue using, albeit illegally, indigenous or recycled materials. The upgrading of such settlements, therefore, automatically meant replacing the indigenous materials with the so-called permanent ones. It is crucial to evaluate the environmental impact of the use of some of the materials that had to be adopted when the World Bank-financed project was implemented in Mombasa. The changes in materials use affected the major components of a house in the Chaani project, such as walls, roofs and f1oors. This is illustrated in table I which shows the changes in the materials used for these components in sampled Chaani houses be/ore and after the implementation of the project. This was the situation during the fieldwork in 1988 (Macoloo, 1989).

Table 1: Changes in materials use in Chaani, Mombasa

HOUSE COMPONENT

MATERJAL BEFORE AFTER

Roof Thatch lron sheets Asbestos/Tiles Others*

79% 13% 5% 3%

26% 67% 5% 2%

Wall Earth Cement Coral Blocks

85% 15% 0%

38% 46% 16%

Floor Earth Cement

79% 21%

18% 82%

*Includes a mixrure of iron sheets and match . Source : Adapted from Macoloo (1989)

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As table 1 illustrates, there has been a progressive replacement of 'temporary' materials with so-ca lIed permanent or durable ones. At present, the house owners in Kenya' s urban low income settlements seem condemned to use ce me nt and iron sheets as the main building materials. Hardly is the climatic factor taken into account. Mombasa , for example, experiences high temperatures and high humidities and has a high atmospheric salinity because of the sea air. These factors affect iron sheets in particular and subject them to swift corrosion, thereby making the roofs unfit for harvesting water for domestic use. In addition, iron sheets are too hot during the day, making a house very uncomfortable and environmentally unfriendly. Despite all this, 67 % of the roofs in Chaani were of corrugated iron sheets.

In discussing the effects on the environment of the choice of building materials in Mombasa, the materials are divided into two categories, namely, organic and non-organic materials.

The Organic Building Materials The organic building materials may be sub-divided into three categories : timber

(which includes sticks and poles); bamboo and cane; and grasses (which include leaves and straws). Timber is used in most countries either as de-barked and sawn or in their natural state in which case it is known as 'country' or ' round' timber. Bamboo culms (i .e. aerial shoots) are also common construction materials in areas where they abound such as Asia because they are straight, hollow, hard and strong. The use of grasses is mainly common in Africa where it is used as roof thatch and requires periodic replacement and regular maintenance.

Generally the use of organic materials is less common in the cities than in the countryside. This is because income levels are lower in the rural areas, the transportation of these materials from the rural areas to the urban areas makes them expensive in cities , and urban buildirig regulations prohibit the use of such materials because they are categorised as temporary. In Tanzania, for example, 45 % of urban walls are made of poles and mud; 20% of the roofs are made of grasses (Wells et al . , 1994). During settlement upgrading , there is a tendency to replace the organic materials, although the poor still use them out of necessity rather than due to choice. Economic impoverishment amongst the majority of the people in developing countries, coupled with rapid population growth, will cause the demand for organic materials to increase in the coming decades . The Word Bank has in fact estimated a 55 % increase in the demand for fuelwood and poles in developing countries between 1987 and the year 2025 (WeHs et al ., 1994).

This projected increase in demand is occurring when these resources are actually diminishing already. Deforestation occurred at 0.8% per annum in Africa during the 1980s. This has been mainly due to non-sustainable commercial exploitation such as excessive commercial logging as weil as population-related factors (rise in demand for building materials and charcoal, clearing for farming purposes , and overgrazing) . Even grasses have become scarce such that in some areas of Kenya, for example, the price of grasses has risen by as much as four limes in recent years. The impacts on the environment of the use of makuti (coconut palm leaf thatch) and boriti (mangrove poles) are examined below.

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Coconul Palm Leaf Thalch (MakwiJ: Thatch is one of the oldest building materials and involves simplicity of house construction. It proved popular because it was abundant, renewable, and has excellent thermal properties. In Mombasa's low income settlements , makuli has been the chief roofing material for most house owners. Before being used as thatch, the dry leaves of coconut palm are woven together to form flat panels. These panels are placed on top of the roof rafters just like tiles or iron sheets . The makuli used in the town originates from Mombasa's rural hinterland. Its production is organised at the household level, with man, wife and children all involved in the production process. Due to the increasing scarcity of the material, some rural households have begun to seil the dry leaves to other households who specialise in producing makuli for sale.

Like other types of thatching material, makuti is becoming rare and this may mean that eventually it may be just as expensive as other materials, particularly if we take into account the fact that thatched roofs have to be periodically repaired. More importantly, coconut palms take a number of years to mature and therefore may begin to compete with other food and cash crops such as mangoes, cassava and maize within Mombasa 's hinterland . This may eventually make the use of thatch unsustainable in the region, and will no doubt call for the search for alternative but cheap and affordable roofing materials. Alternatively, if it becomes more profitable to produce makwi due to high demand and scarcity, this will undoubtedly interfere with the production of food crops in the region.

Mangrove Poles (Boriti): The use of mangrove poles for house construction is also widespread in Mombasa. Boriti may be used either as vertical structures for walls or as a substitute for timber as a roofing material. It is usually cheaper than timber and almost just as durable if treated be fore use. This material is also transported from Mombasa's hinterland into the town for sale by middlemen. Mangroves are normally cut before they are barked and transported to areas of demand. Destruction of mangroves may lead to the depletion of fish stocks because fish and the creatures they feed on breed and inhabit mangrove regions. Furthermore, quantities of silt that would otherwise be captured by the mangrove filtering system enters the sea and may suffocate coral reefs which is another important breeding and feeding ground for fish. Mangrove depletion along the Kenyan coast has resulted in some serious environmental degradation in the region (Syagga, 1994) . Along the Kenyan coast, sand dune encroachment is increasing and gradually affecting the coastal vilJages around Mambrui to the north of the tourist town of Malindi. This is due to the destruction of mangrove forests which have been over­exploited for building purposes.

The Non-Organic Materials

Only two non-organic materials, sand and coral blocks, whose use has been intensified in Mombasa since the implementation of the project are examined below to illustrate the impact on the environment.

Sand: As a building material, sand is hardly used alone. It is normally mixed with other materials before being used . The use of sand has been intensified with the increased utilisation of portland ce me nt in Mombasa's low income settlements (see table 1). Like

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the production of makuti, sand production (i .e . quarrying) occurs in the rural areas surrounding Mombasa. Sand quarrying is carried out either in partnership or individually. Its production involves certain interest groups such as land owners because much of the sand used in Mombasa is· not river sand. Sand quarrying is a well-organised activity involving the two chief classes of capitalist mode of production, namely, the producers and the non-workers . The prospective entrepreneur (non-worker) identifies and rents a sandy tract of land before production can commence. Then workers (sand diggers) are contracted on a daily remuneration to quarry the sand.

This activity results in disused wide tracts of open quarries which accelerate soil erosion and may be a hinderance to future agricultural productivity in the areas that produce sand. Such wanton degradation of the envirorunent is only possible due to the fact that the majority of the sand producers do not own the land from which they quarry the sand, and the lease agreement does not incorporate any mandatory requirement to rehabilitate the quarries once sand harvesting ceases. In some rare situations, concerned land owners have attempted to reclaim these quarries by planting rice in them . This is the case in the Tiwi area of Kwale District from where a substantial amount of sand is derived for Mombasa' s construction sector. This form of quarry regeneration should be encouraged and incentives provided for such activities otherwise the envirorunental damage that sand quarrying causes may be irreparable in the long run.

Coral Blocks: Because of the sedimentary nature of the stratigraphy of the coastal region of Kenya, the use of coral stones in house building is an old practice. What may be relatively new is the dressing of the raw stone before use. Coral blocks are more commonly used than concrete blocks in Mombasa's low income settlements partly because of their abundance and relative cheapness (table 1). The stone is quarried both within the vicinity of Mombasa as weil as in the rural hinterland. Within Mombasa's municipal jurisdiction, the main concentration of quarries (known locally as timbo) is found on the South Mainland at Likoni. The production of coral blocks, Iike sand quarrying, involves fractions of vested interests such as land owners and middlemen. The producer, if he does not own landhas to rent it at a negotiable price before quarrying can commence. The block production beg ins when the top grass and soil are removed to expose the layer of coral stone. The stone is then measured up in two main sizes (15 cm by 23 cm by 46 cm and 23 cm by 23 cm by 46 cm) before quarrying commences. The stone is generally dressed atthe quarrying site before being transported to town for sale .

Just like in the ca se of sand, the quarrying of coral blocks results in envirorunentaJ damage because the quarries are left unfilled and unreclaimed . Also the heaps of top soil wh ich are removed before quarrying commences are not properly disposed of. In addition to being a safety hazard, such careless treatment of quarries renders these areas totally useless for any immediate activity . The main producer of portland cement, (he Bamburi Portland Cement Company which is based in Mombasa, has demonstrated that abandoned or disused quarries be successfully and profitably reclaimed. The company has developed a 'nature trail' farm on its disused quarries by planting rapid-growing vegetation and introducing wildlife such as monkeys, tortoise and a varietry of birds. These reclaimed areas have proved to be extremely attractive spots for tourists, and therefore the nominal entrance fee charged to visitors make the regeneration of these quarries self-sustaining. An individual entrepreneur in Mombasa has also taken these ideas on board and

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reclairned deep disused quarries by raring eroeodiles in them, thereby ereating one of the most popular eroeodile farms in Afriea. These examples illustrate that environmental degradation amplified by the produetion of and demand for building materials ean aetually be eurtailed in a surprisingly profitable way.

CONCLUSION

Construetion aetivities are essential to all aspeets of development, and it would therefore be irnprudent to restriet eonstruetion aetivities . Due to the population inerease and the intensifieation of human eeonomie aetivities , there tends to be an over­exploitation and mismanagement of the world's finite resourees. The building materials sub-seetor of the eonstruetion industry is a major user of natural resourees as people attempt to provide adequate shelter for themselves . The over-exploitation and misuse of the natural resourees for shelter provision has been shown to have degrading effeets on the environment , thereby posing a dang er to the sustainability of both the eonstruetion industry itself as weil as that of the resouree base. For sustainable eonstruetion seetor to thrive, three issues need to be addressed. The first is the sustainable management of eonstruetion resources or raw materials. A number of options sueh as re-afforestation, soeial forestry projeets ete. should be eneouraged . Legislation should be tightened to make it 'expensive ' to abuse or misuse eonstruetion material sourees sueh as forests. The second issue eoneems the deterioration of the physieal environment. It has been demostrated that environmental degradation ean be minimised . The govemment eould take the lead in this are by managing its resourees properly . Finally, the development of alternative building materials that utilise abundant loeal resourees should be researehed on otherwise the eonstruetion industry in Kenya may prove, in the near future, to be unsustainable and expensive .

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Kenya, Govemment of, 1966 The housing poliey for Kenya (Sessional Paper No. 5 of 1966/67), The Government Printer, Nairobi.

Kenya , Govemment of, 1990 Housing poliey for Kenya , The Government Printer, Nairobi.

Maeoloo, G. C. 1989 The eommodifieation of urban self help housing in Kenya: an analysis of the nature of the ehanging produetion and eonsumption of building materials in Mombasa, Unpublished PhD thesis, Cambridge University .

Maeoloo, G. C. 1990 Aeeeptability as a faetor of sueeess in development projeets: Kenyan lessons for Namibia , Paper presented at 'Town and Regional Planning

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Conferenee' in Windhoek, Namibia (Oetober 26-27, 1990).

Maeoloo, G. C. 1994 The changing nature of financing low income urban housing in Kenya, Housing Studies, 9(2), 281-299.

Syagga, P. M. 1994 Promoting sustainable construetion industry activities in Kenya. ACTS Research Memorandum No. 8, Nairobi (Available from ACTS P. O. Box 45917 Nairobi, Kenya) .

USAID, 1979 Kenya shelter sector study and the AID's experience. Regional Housing and Urban Development Office, Nairobi .

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Wells, J., F. Haddar, D. Wall and M . Page 1994 Links between population, settlements and the environment: the provision of organic materials for shelter: a literature review. South Bank University, London (Available from Sehool of Construction Economics and Management, London SW8 2JZ, U. K.).

World Bank, 1978 Kenya second urban project: project implementation file voll & 2. Washington D. C.

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