But could the technology, as well as the vocabulary, of housebuilding be set to change?
Former housing minister Lord Falconer saw modular housing as the answer to the housing problems of key workers; others see off-site build technology as the solution to other challenges – skills shortages, the Egan agenda, ever more demanding building regulations and the quest for quality improvement.
"We are now acting as innovation consultant to quite a number of registered social landlords," says Darren Richards, operations director of technology consultant MTech Group. "The vast majority of our housing work is in the social and key-worker sector. Not a lot is coming from the private housebuilding industry."
"We now have a succession of projects," says Peter Jenkins, national account manager with modular building maker Yorkon. Like MTech, Yorkon is working primarily with RSLs, notably supplying the Peabody Trust's Murray Grove and Raines Dairy schemes in London, although it is hoping to land a contract with a private housebuilder later this year.
This ongoing activity has convinced Yorkon to dedicate a production line to manufacturing modules purely for housing projects, although it acknowledges that the housebuilding industry has not yet learned to love prefab.
"After Murray Grove, we were inundated with people coming to us and asking us to modularise schemes, but that is not the way to do it," says Jenkins. "Developers have to come to us with a clean sheet of paper and buy in to the process. Before Murray Grove, about 10% of the profession were prepared to get an understanding of what we were doing. Now it is 25%, but that still leaves 75% who are not prepared to understand."
"Things are changing," agrees innovation consultant Tony Redhead, whose company, Redex Consultancy, helped bring Dutch technology to Southern Housing Group's Nightingale Estate project in Hackney, east London. "But change is slow because people are afraid of bearing the cost of lower productivity while they go through the learning curve of new systems. Contractors' quantity surveyors are too inclined to just look at cost per item."
Hand in hand with the gradual increase in demand is coming a more rapid increase in supply of technology. UK building products companies are now more eager to introduce new systems, many of which have been available overseas for years.
"We couldn't have brought the Jamera prefab system here five years ago – the environment then was different," says Ian Exall, marketing manager of aircrete blockmaker H+H Celcon, which is about to start UK production of the aircrete floor and wall panel system that its Finnish counterparts have been selling for 20 years.
"It's a turnaround from two to three years ago when people didn't have a choice," says MTech's Richards. "We have just carried out an analysis of light-steel framing and found 11 companies capable of supplying to housing projects. There is so much motivation and drive coming out of the steel frame sector." And costs, he says are coming down.
Yet in spite of this improved climate of innovation, the most common off-site build technology, timber-frame, has failed to increase its share of the market in England from around 10%. "It has been there since 1999 and has remained relatively static," says Geoff Pitts, technical director of innovation consultant the Palmer Partnership.
"It is possible that there has been no more capacity in timber-frame factories to produce more," he adds by way of possible explanation. If that has been the bottleneck, then it is easing. Stewart Milne has just opened a 4000-unit-a-year capacity factory in Witney, Oxfordshire, and both Westbury Homes' Space4 factory and Partnerships First's Torwood2 works are gradually stepping up their production lines. Canadian timber-frame producers are mounting a campaign to enter the UK market, backed by their government. A new UK timber-frame initiative, the Homes Factory, is looking to satisfy demand on smaller sites by establishing small locally based micro-factories, to offer the quality of factory build without the cost penalty of big factory overheads.
But before you rush out and cancel your order for blocks and replace it with one for steel or timber frame, it is worth heeding the advice of prefabrication's pioneers. "It is not simply a matter of replacing one material with another," says Robin Davies, the Westbury Homes board director responsible for Space4. "The biggest challenge is in integrating the new process of building the shell with the old processes of the site."
The housebuilder is now doing its first "continuous build" projects, but the process is not yet seamless. "We've found that in one or two areas of the country we used all the scaffolding available because we needed so much over a short time," says Davies. "So now we are looking at ways of putting up the shell without scaffolding, working with the HSE and others. This is just the first generation. We're taking the whole construction process forward."
It seems learning the difference between a SIP and a pod could therefore just be the start.
Prefabrication: a beginner’s guideTimber frame
What is it?
The term “timber frame” has become something of a catch-all for most forms of timber prefabrication, from the most basic stick-build upwards. The latest systems to appear on the market are Structural Insulated Panels (SIPs). These are structural elements made of two sheet materials sandwiching a rigid foam core. The latest wall panels may have doors and windows and services conduits all fitted into them in the factory. Where can I see it?
Around half of Scotland’s new homes are built of timber frame, as are 10% of new homes in England. Westbury Homes is just starting to build complete sites of houses on a variation of the SIPs theme, made at its own Space4 factory in the Midlands. Manufacturer Kingspan has a SIPs system called TekHaus, and will be building a demonstration house at the Zethus centre for housebuilding innovation, at the University of Greenwich in Dartford. What’s coming next?
The Home Factory, a new enterprise that aims to bring prefabrication to smaller housebuilders through local project-based micro-factories, and provide training at the same time. And Westbury’s Space4 factory will have produced, by the end of this financial year, around 1500 units. It will then sell SIPs to other housebuilders.
What is it?
It is similar to timber frame, but has failed to make the same impact on the marketplace. The growth of higher-rise urban apartment development has, however, given it a boost. Where can I see it?
The largest steel frame housing project is Oakridge Central Regeneration estate in Basingstoke, Hampshire, where some 300 homes designed by HTA Architects are being built by Forge Llewellyn for Oakfern Housing Association. What’s coming next?
Southern Ireland-based Fusion Building Systems’ steel-frame panel system, with a foam-filled core, has impressed housebuilders that have been to take a look. Also exciting interest are hybrid systems including Corus’ EU-funded FutureHome project with international partners, which combines steel panel with a services and circulation core module. But the real one to watch is the Peabody Trust/Forge Llewellyn’s Lillie Road project, which combines steel panel with structural bathroom pods ('Prefabs with a difference').
What is it?
Housebuilding industry interest has mainly concentrated on tunnelform construction, following the example of Dutch housebuilding practice, and on precast concrete panel systems such as H+H Celcon’s aircrete-based Jamera product. Where can I see it?
The most prominent tunnelform project in the UK is at the Nightingale Estate in east London, where housing association Southern Housing Group is combining tunnelform with other Netherlands-based innovations, such as timber wall and roof panels, in a scheme designed by Watkins Grey Architects. Celcon’s Jamera system has been trialled by Laing Partnership Homes for a small-scale housing project in Bethnal Green, east London. What’s coming next?
Southern Housing Group’s proposed successor to Nightingale, which might take tunnelform further. And consultant Redex is finalising a joint venture with a UK precast concrete manufacturer and Dutch manufacturer Sterck, which will see Sterck’s concrete wall panels with whole-brick facing manufactured in the UK.
Pods and modules
What are they?
Basically, these are all boxes, albeit of varying sizes, made most commonly from steel. They are already commonly used to build hotels and, famously, McDonald’s restaurants. Fully volumetric homes have been trialled in the apartment sector by the Peabody Trust at Murray Grove and Raines Dairy, and they are being touted as ideal for the capital’s key workers. But in the private housing sector, it is bathroom pods that are being given most serious consideration, bathrooms being the most labour-, services-intensive and quality-sensitive rooms of the home. Where can I see them?
Yorkon modules are being stacked on site at the Alford Hall Monaghan Morris-designed Raines Dairy scheme in Stoke Newington, north London, for the Peabody Trust. Site progress is visible on website: www.yorkon.com/rainesdairy
What’s coming next?
LiveIn Quarters, in which Peabody Trust has an interest, is set to be the next player to enter the prefab sector. It is targeting London’s key workers and was showing off high-tech micro-flats at this year’s Daily Mail Ideal Home Show in London. It is now looking to set up its own factory in Essex.