Pergamon

01973975(93)EOOO6-9

Building Materials for Housing: a Rejoinder*

ROBINSPENCE University of Cambridge, UK

As the principal author of the Report of the Executive Director of United Nations Commission on Human Settlements published in this journal, I would like to respond to some of the comments made by Jill Wells in her communication.

Jill Wells. as an economist. has considerable experience of worldwide building materials production processes, and the addition of the many observations she makes based on that expcriencc is wclcomcd. In particular she is right to point to the paucity of data on the progress, glohillly. of many apparently promising new tcchnologics. She is also right to point to some failings of those tcchnologics which are not mcntioncd in the Report - failings which will have i~tlvCrSCly ilffCCtCd their attractivcncss COlllpilrCd with more convcntionnl tcchnologics. Problems of <lu;llity control ;\rc certainly important among thcsc. She is right to point out thilt the quality of the ccmcnt produced in small-scale plants in China and Vietnam is well short of that produced in large-scille plants. and that whcrc small-scale IJlillltS d0 product to international f’ortland ccmcnt StillldilIdS, ilS in India, the cost of such ccmcnt is much the same as in large-scale plants. and cncrgy costs ;lrc hi&r. It is illso true that several ot’ the tcchnologics rcferrcd to ils being able to bc produced cntircly from local rcsourccs dcpcnd on inputs of ccmcnt which in some countries is still importcd.

Thus if the main thrust of her argument was thitt the newly devclopcd building materials tcchnologics specificillly ilimed at the dcmnnd for IOW cost, l<>ci~lly produced illtcrniltivcs I~:IvC not achieved all Ihilt wits hoped of them, I would readily agree. But Jill Wells goes further. The gcncral thrust of her argument seems to bc that because these new technologies have not yet taken off in a big wily, WC must judge them - and the whole technologicitl approach - i1 failure and look for an alterni~tivc approach. This conclusion should be resisted for a number of reasons.

First of all, it stems to mc far too early to write off the newly developed building milteriills technologies as ;t failure. Most of these technologies are still extremely young: stabiliscd soil has been around for perhaps 20 or 30 years in Zi fCW PlilCCS, much less in most; fibrc concrete roofing is hardly 10 years old; mini ccmcnt plants on the Indian model did not appear until the early 1080s; lime-pozzolana ccmcnts have been tried only in :I few isolated places. By contrast the cstiiblished large-sc:ilc tcchnologics of production - Portlilnd ccmcnt. steel sheet production. continuous brick firing - have been around for more than ;I century, itnd it hiIs taken them all that time to reach their present position of market strength and technological efficiency. Very little effort has been dcvotcd to R&D in the new materials compared with that

‘Executive Director of The Unit& Nations Commission on Human Scttlcmcnts. “Building blatcrials for Housing”. I~aahirur I~~r~rcrriorrol 17. 2 (IYY.3). pp. I-20.

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devoted to established production processes; and we have yet to see effective mechanisms for transferring successful small-scale technologies except in the centrally planned economies. It is therefore not at all surprising that there are problems of quality control, and that production costs are not significantly less than those of established technologies. But both quality and cost are likely to improve as they become established. The conclusion of this might be that massively more effort needs to be devoted to R&D in these technologies; and this is one reason for the emphasis placed on them by UNCHS in its recommendations to Governments.

Secondly, it seems essential not to write them off because the alternative is increased dependency of the developing countries on the technology. capital and expertise of the industrialised countries. In many places, the choices available for building materials are between very low-performance materials such as earth and thatch on the one hand, and manufactured products such as cement-based blocks and steel sheets on the other. In this situation, improving the performance of traditional forms of shelter involves becoming dependent on the trans-national companies which control these large-scale production technologies, and on internationally established pricing structures. Technology will only be successfully diffused if there is an entrepreneur who will benefit. It is very much in the intcrcst of the dcvcloping countries if these entrepreneurs are local enterprises rather than trans-national companies.

Thirdly, it is essential not to write them off, bccnusc they arc in the direct line of technological progress. The situation faced by cvcry dcvcloping country is one of rising population. rising cxpcctations and iL dwindling rcsourcc base. The central thcmc of the Report is that it bccomcs csscntial in thcsc circumstances to ICilrIl to do more wilh 1c.s.s. l‘hc whole history of production technology Ciln

bc seen. at one Icvcl. as ;I process of gradually improving our cflicicncy in the USC of rcsourccs. Nowhcrc is this more important than in the building industry, because building uscs materials in such huge quantities. 13ut whcrcas, in the past, the dcvclopmcnt of production technology has been conccntratcd in the now industriilliscd countries, WC must IlOW find WilyS to StilllUliktC iI fnussivc upsurge

of innovi\tion ill1 over thC world, iIS ;L rcsponsc to IlKal CiKUlllStilllCCS. and Lit all scales of production. The UNCHS report dots not, as Jill WCIIS claims, take the position that small-scale technologies arc a panacea: it explicitly acknowlcdgcs that production processes at all scales will be ncedcd.

The UNCHS-proposed programmc, then, is one of progress based on widespread innovation illld experimentation using locill rcsourccs. This is necessary, realistic, and in lint with historical expcricncc: but certainly much faster progress is ncedccl than WC have been seeing over the last two decades.

By contrast, the programmc advanced by Jill Wells is one of regenerating and expanding the resource base without a significant role for improved technology. But while, certainly, there may be ways in which it will be possible to expand supplies of conventional materials - bamboo in Bangladesh for example - this will inevitably involve longer and longer transportation as populations and pressure on the land incrcasc. In general it is difficult to see how the global resource base can bc expanded to provide more building materials, when all the evidence suggests that the expansion of population and rising living standards will inevitably continue to dcgradc it further, and faster, in the future. This is why we must have improved technology.

It is quite true. as Jill Wells says, that thcrc is a mismatch between the mounting crisis of building materials supply and the apparent capability of existing ,tcchnological options to meet the demand - and this is precisely why the massively increased effort on the part of industries. govcrnmcnts and aid agcncics which the Report of the Exccutivc Director calls for is so urgently needed.