Professor Trevor Mole
For many of us in the UK the mention of pre-fab immediately brings to mind those temporary buildings which were built just after the 2 nd World War as an answer to homelessness. The pre-fabs much loved by many of their occupants were generally two bedroom, factory built bungalows designed to a standard plan and equipment. They were designed to last for ten years and most lasted at least 25 years. Some are still around today. Last year the Department for Culture, Media and Sport listed sixteen pre-fabs as historic buildings.
The concept of prefabricated houses is perhaps as old as, simple tent structures.
However in the UK it was the need to build large numbers of houses quickly after the war which led to an unprecedented increase in prefabrication and industrialisation. Prefabrication is off-site manufacture and can be volumetric
(or modular ) as it refers to complete modules such as bathrooms or panellised which involves individual elements. Industrialisation is mechanised operations dependant on fully integrated processes of demand, design, manufacture and construction. Industrialisation requires emphasis on rationalisation, standardisation, repetition, greater user of factory made systems and more effective use of management and new techniques. Not all industrialised buildings relied on factory made components. For example, concrete buildings such as ‘nofines’ relied on standardisation and the re-use of temporary formwork. However many industrialised “system-built” houses relied heavily on factory made components that were simply assembled on site. The results were generally pretty disastrous particularly in high rise, but before we review the problems it is interesting to look at the pressures on Government and local authorities at this time.
The Government White Paper, Housing, in 1945 estimated that 750,000 dwellings were needed to give each family a separate dwelling. By the end of 1946 one third of a million units had been provided by building pre-fabs, conversions and adaptations, temporary huts, requisitioned houses and 52,000 new permanent houses. In 1946 a programme for permanent houses was established and a national target was set at 240,000 houses a year. Additional subsidies were made available for more expensive types of non-traditional construction which were encouraged in order to offset the shortage of skilled building labour and of certain traditional building materials. In 1947 127,541 houses were completed and by
1948, 206,559 had been constructed however it was realised that the building
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industry was overloaded and the target was reduced to 200,000 a year. In 1953
Harold McMillan as Minister of Housing had pledged himself to reach a house production of 300,000 but the problem again was to avoid overloading the industry and the economy. There was also major concerns about shortages of skilled labour. Both Conservative and Labour politicians in the early sixties pledged themselves to step up house production to 500,000 houses a year. To this end, the use of industrialised building methods was encouraged, and “much thought, skill and money have been put into developing industrialised building systems for flats and houses” Richard Crossman, Minister for Housing and Local Government,
May 1966.
Industrialisation and in particular factory-built systems of construction was seen as the utopia. It was an answer to skill shortages and an overburdened industry. It would produce better quality factory made components and after a lead in time, dwellings could be created quickly and given the scale (around 100,000 by 1970) it would be economic.
The present demand for new housing in the UK is enormous and must have been one of the drivers for the Deputy Prime Minister, John Prescott to set up a task force on Construction in 1998. The task force chaired by Sir John Egan of Jaguar fame, reported on an industry that was considered to be under achieving with low profit margins, and which invests too little in capital, research and development. It reported that clients were generally dissatisfied with the industry’s overall performance. The agenda for change identified five key areas for change, committed leadership, a focus on the customer, integrated processes and teams, a quality driven agenda and commitment to people.
The report emphasised the advantages of Standardisation and Pre-Assembly and stressed the importance of re-engineering and modular industrialised systems in housing. The experience of the Dutch ‘Open Building’ approach and ‘modular housing systems’ from Japan were suggested as possible models for application in the UK.
The noti on that industrialisation was the answer in the 1950’s and 1960’s led to many disasters. Industrialisation, prefabrication and system building developed some of the worst buildings ever produced in the UK. As well as the contributing poor social and environmental factors, many of the buildings failed because they were poorly constructed, unsafe, riddled with defects and after a short time were uninhabitable. Buildings expected to last 90 years, for example the infamous
Hulme Crescents in Manchester, were completely demolished and redeveloped after only 30 years. System buildings which remain today are generally expensive to maintain and often unpopular amongst occupants. It is not difficult to create a list of causes of failure but the lack of technical understanding, attention to detail, poor workmanship and lack of management, are all significant contributors.
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Industrialisation and prefabrication as an answer to the post war skilled labour shortages was perhaps the biggest fallacy. In fact, it was poor workmanship, the use of unskilled labour, the lack of understanding and skill in the new technologies that were the major contributor to the physical failures of the prefabricated buildings of the 1950’s and 1960’s.
Perhaps of greater significance is the stop, start, go fast, go slow fluctuating commercial and economic environment in which the construction industry operates. In 1966 over 1million people were employed in the building industry. In
1972 it had reduced to 835,000 and in the 1975 recession 350,000 of these workers were unemployed. As Egan pointed out and as we all know, it is difficult in the UK to attract the best people into our industry. But as in the 1950’s and
1960’s the pressure is on for the construction industry today to respond to demand. Now as then, housing is of primary, social and political importance and the demand for an estimated 3.8 million new houses by 2021 is driving an industry to increase production, improve quality, improve on safety and give more for less money.
The question often posed in the context is why can’t houses be more like cars? Buildings that can be mass produced but customised to meet user expectations and requirements.
The impetus driven by Egan and the Government sponsored Construction Best
Practice Programme has put prefabrication higher on the agenda. Over the last twenty years the use of prefabrication has been limited. Many different systems including steel framed, concrete box structures, concrete panelled and aluminium structures have been built. There is a huge variety and permutations but in terms of the total UK stock the numbers are quite low. The most significant has been the production of prefabricated timber framed, low rise houses which have continued to develop despite some bad and many would say unfair publicity. There are many issues to consider in the timber frame debate. However, unlike other housebuilders who have abandoned timber frame, others like major housebuilder,
Wilson Conolly are investing heavily in factory built timber frame despite some pessimism from City investors and market pundits. Prefabricated timber framed construction has been widely used in the UK. Many believe it provides high quality houses, quickly, cost effectively and efficiently and that new energy efficiency requirements introduced in Part L of the Building Regulations due in the near future will be relatively easy to implement.
Timber framed construction was badly effected by adverse publicity in the late eighties. Again the issues were mainly lack of understanding and poor workmanship in assembling the buildings on site. Lack of continuity of vapour checks and failure to properly integrate building services caused moisture and condensation problems. Customer perceptions are still considered by many to be against timber frame construction. Most timber framed houses in the UK are clad with traditional external facing brick which disguises the timber framing on the inside. The British have a love affair with traditional brick/block house construction which provides a feeling of security and reliability. Whilst some may be willing to accept timber on the inside, on the outside it should look like any other. New timber systems of Structural Insulated Panels or SIP’s are being developed and
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could take off in the UK. These use two skins of strand board sandwiching a foam plastic core providing a monolithic structure that requires less bracing.
The Housing Corporation which is responsible for investing public money in
Housing Associations which are Registered Social Landlords has also set in motion seven pilot projects using timber and steel frame systems with a budget of
£80m over two years.
The Building Research Establishment (BRE), has recently analysed two prefabricated social housing developments. Murray Grove completed in 1999 is the first multi-storey prefabricated modular residential construction in the UK. The second was the Joseph Rowntree Foundation’s CASPAR scheme completed in
June 2000 providing city-centre apartments for single people at affordable rents.
BRE’s conclusion is that prefabrication can reduce construction time significantly.
The process is easier to predict and meet timescales and the product is more defect free. Both projects were around 5% more expensive than conventionally built properties but in prefabrication economies depends heavily on volume and specification.
Unquestionably the pressure is on from Government to increase and improve the
Construction Industry’s productivity. The great danger, like in the post-war years, is that the industry, along with its clients, are pressured into using untried methods of producing houses which, in the longer term, may prove disastrous in terms of cost, environment and technical performance. The Governments commitment to
“A Decent Home for All”, introduced in December last year is widening the task to include urban regeneration, which although sensible, adds to the complexity of finding good solutions and slows down implementation. The Department of
Transport Local Government and the Regions’ policy is to bring a third of all social housing up to a decent standard by March 2004 requiring 300,000 houses to be upgraded and 25,200 new houses to be built in the same financial year.
Refurbishment will ju mp from £3.48bn this year to £4.41bn in two years time.
Ambitious!?
The construction industry is under enormous pressure to deliver. Last year the industry produced 137,000 homes, the lowest since 1924. Response to Egan has been slow especially amongst
SME’s which make up the majority of the Industry’s employers. The industry for many reasons, does not respond well to innovation and the bad experiences of the past gives it cause to be cautious. However attractive or justified prefabrication may be there are many barriers to overcome particularly from the city, consumers and planners. Unquestionably without the advantage of secure, economic volume production new prefabrication methods will be difficult to implement.
People who live in the UK are conservative when it comes to housing. They prefer conventional construction above all because it has proved reliable over decades, when system built, prefabricated industrialised construction has failed them.
Worries about long term value, brought about in part by scare stories and wrong
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perceptions have contributed to consumers being sceptical and resistance to new methods of building. Nevertheless changes in attitude, however slow is happening. For example, the growth in self-build which uses prefabricated timber frame construction is experiencing steady growth.
Prefabrication is not the answer in itself, but sustainable housing is. Unlike the post war experience there is now much more joined up thinking and greater awareness of what is needed in providing sustainable communities with decent house amenities and environment. There are many issues to grapple with for example in accommodating the use of local materials and homegrown woods from sustainable forests. In Scotland at least 500 tonnes of stone becomes available for re-use through demolition with only a small amount recycled. The environmental cost of transportation is also significant. Prefabrication of complete modules in the end have to be small enough to go on the back of a lorry and be transported to site. Energy efficiency is important and whilst prefabricated buildings may be relatively easy to insulate they are generally much more difficult to make airtight and prevent ventilation energy losses than conventional construction. Furthermore the lack of mass often makes sound insulation required under part E of the Building Regulations more difficult to achieve in lighter prefabricated structures.
Perhaps one of the most important issues to consider is that prefabrication does not on the whole reduce the need for skilled people. Experience has shown that a reduction in the need for traditional building trade skills is off-set by the need to develop new skills and competencies amongst the workforce. Not surprising research at the University of Westminster identified that skilled labour supported by quality training at all levels is essential to success in prefabrication as it is in more traditional forms of construction. The report, which is due to be published at the end of the year argues that occupational hierarchies work against integration and understanding amongst the team. De-skilling is not the answer and prefabrication is not a quick fix for the loss of skills in construction.
It is important that the UK Construction Industry continues to respond to the Egan drive to innovate and to change. This is perhaps most important in the field of housing with its mix of social, economic and political pressures demanding action.
Unquestionably the industry like in its post war years has an enormous expectation to fulfil. It is not just about productivity but about best value. Perhaps the biggest enemy is time and whilst government may want to see action quickly it is important to ensure that solutions are not delivered without being fully tried and tested. Egan principles, like procurement methods are usually better when an adequate lead-in time is provided. Prefabrication has its place in house building, but it will take time to effect a significant change. However it is imperative that prefabrication is not seen as the panacea for all ills and failure to recognise its limitations in overcoming skill shortages and increasing productivity could be disastrous.
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Driving the Egan agenda into every area of construction including repairs and maintenance, SME’s, private house builders, etc. is important if the industry is to deliver. The mind set should focus on being innovative at the micro-level as well as the macro. So much of our traditional building techniques could do with a dose of the Egan medicine. Concepts of industrialisation could be applied to many existing methods and with the right approach perhaps more components and construction techniques could be standardised, rationalised and repeated.
Perhaps this will then lead to greater use of prefabricated modules and components. The concept of buildings being produced as a branded factory produced product is probably some way off. However, prefabrication is set to increase quite dramatically in the UK and with the right approach it will not be a question of having been here before but will be a completely new and exciting way of working.
Rethinking Construction, Department of the Environment, Transport and the
Regions: London, July 1998 ISBN 1-85112-0947
The Decent Home Guidance, Department of the Environment, Transport and the
Regions : Stationery Office Ltd, Norwich, July 2001
Building Regulations, Part E Sound Insulation, Part L New Energy Efficiency
Requirements
Prefabricated Housing in the UK, Parts 1-3 Building Research Establishment,
Watford, September 2001 ISBN 1-86081-495-2, 4, 6.
Sustainable Housing Principles and Practice, Edwards and Turrent, ESF Spon
London, 2000 ISBN 0-419-24620-7
Standardisation and Skills : A Transitional Study of Skills, Education and Training for Prefabrication in Housing to be published by the University of Westminster’s
Business School late 2001
Useful Websites www.housing.dtlr.gov.uk
www.english_heritage.org.uk
www.barbourexpert.com
www.scotland.gov.uk
www.housingtoday.org.uk
www.thehousingforum.org.uk
www.cbpp.org.uk
www.housingcorp.gov.uk
www.salford.ac.uk/scpm trevor.mole@property-tectonics.co.uk
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