Modern methods of construction are now being used on all manner of projects, from restaurants to naval bases. Mark Faithfull looks at the latest developments and asks: could this be the age of off-site?

When the government announced an investment war chest for construction projects last year, the off-site industry rubbed its collective hands with glee. Schools for the Future, the Procure21 healthcare programme and the Ministry of Defence’s Single Living Accommodation Modules (SLAM) initiative, not to mention the need to create affordable housing quickly in the over-subscribed South-east, were all seen as unmissable opportunities for the proponents of modern methods of construction to prove that their solutions could be not just time-savers but cost-effective to boot. After several years waiting at the door, opportunity had surely knocked.

A few years ago this would have been unthinkable, but off-site manufacture has become credible once more against the healthy backdrop of a construction industry now used to demands for greater productivity and efficiency. “In our view OSM is definitely maturing into a very versatile, though not universally applicable, tool in a kit of parts,” says Tim Venables, a researcher at the Tanaka Business School at Imperial College, London. Venables, co-author of several reports on OSM, senses a gathering of momentum: “OSM tackles building skills shortages, it takes on-site tasks and brings them into the factory – in an age when our country is in manufacturing decline – and we have to think this makes it quicker, safer and cheaper than working in a building-site environment.”

Of course, the industry is still coming to terms with its new tool. Venables warns: “We’re looking at a traditional industry, albeit one that is much more flexible than it used to be. OSM still makes some housebuilders nervous when it comes to lending and insurance issues and they also need to see a definite advantage, which translates to the bottom line.” Increasingly though, these nerves are being calmed by a series of landmark projects up and down the country.

Grand designs

Some forms of OSM have forged ahead of the pack. Timber frame technology is currently reckoned to have an 18% share of the residential market, though this is still fairly small compared with the Scottish market, where the share is over 55% for new residential demand. Technologies such as closed-panel technology and structural insulated panels (SIPs) have been developed to aid the delivery of fully finished panel systems.

Hot on timber frame’s heels is steel frame, with companies such as Irish-based Fusion and steel giant Corus throwing their hats into the ring. Though timber systems are evolving from low-rise to medium-rise structures, steel is more strongly associated with taller buildings and is now challenging in the low-rise domestic arena.

The improvements in technology are beginning to overcome a classic OSM fear: that design is the first casualty. Take contractor Wates’ 77-apartment Riverside project in Cambridge. Intended, much like the lauded Murray Grove project in north London, to prove that modular does not have to mean a design bypass, the five-storey, £9.1m project is constructed with manufacturer Fusion’s frame system. In June, British Land purchased 54 units from Wates for £16m, with handover of all units scheduled by the first quarter of 2005.

John Rivett, Wates’ design director, admits that it has been a steep learning curve. “I’d liken it to riding a bike for the first time,” he reflects. “You start off wobbling but the more you do it the steadier you get. We’re in a situation where the suppliers are also doing a lot of educating, explaining to companies like ours how their systems work. So we’re making sure that our teams are intimately involved with our supply chain so that they get the maximum amount of learning out of the process.”

Further north, developer Urban Splash is behind what it claims is the first development of modular homes for private sale in the UK. Moho, a 102-apartment scheme designed by Shed KM and manufactured by Yorkon, is the latest phase of its brownfield Castlefield development in Manchester.

The company says that it has played up the use of OSM in its marketing material and believes that buyers are interested rather than concerned about the construction method. “We launched the project in June at an investor show and displayed a full module outside the G-Mex Centre, which raised a lot of interest,” says a company spokesperson. The apartments will be ready to move into in spring 2005. The spokesperson says: “We’ve sold just over a third and when the units are fully in place and the showrooms open this month they will be sold on the basis of how they look. They really are a million miles from the old prefab buildings and the OSM element will become a side issue.”

“OSM has been accused of putting up standard boxes – these projects show that’s not the case,” says Imperial’s Venables. “On a recent research trip to Germany, where the OSM sector is far more evolved than in the UK, I can say we saw everything from designer apartments to mountain chalets.”

… and now from schools to pizza parlours

Moho, like fellow Yorkon project Murray Grove, represents the headline-grabbing volumetric end of OSM. Yorkon is also responsible for such disparate contracts as Pizza Hut’s new-build programme and last spring’s completion of Our Lady of Lourdes school in East Kilbride, Lanarkshire, the first fully modular school to be built in the UK.

Similarly, contractor Mansell is into the eighth phase of a long-term partnership with the Royal Navy’s training arm at HMS Collingwood in Fareham, Hampshire, where it started on site with lead contractor Flagship in January 2002. It is using volumetric units from Caledonian Building Systems for accommodation blocks of 98 rooms on average, and has completed more than 1000 rooms so far. “There was undoubtedly some learning from phase one,” says Andy Duff, Mansell construction director for HMS Collingwood. “We realised that more work had to be done at the design stage; we sat down with the client and went through samples of everything – right down to door handles. Seven stages on and the units are being delivered part decorated with only the second M&E fix, carpets, final decorating and loose furniture to install.”

Duff says that an average-sized block will be delivered over eight days and takes about 17 weeks to complete once on site. On speed he is convinced, but what about cost? “At this point the cost is just about comparable, providing that there are not a lot of site complications or variables,” he says.

“The OSM sector has to prove that it can build at the same price as the traditional market,“ says John Miles, principal director of engineering and architectural group Arup. “In the past, once the government money went, so did the impetus. OSM has to overcome this challenge.”

Miles, who has been working on an OSM system for Arup, believes the key is to intermarry the disciplines. “Construction has no history in manufacturing processes and it’s a completely different mindset. To achieve factory-style efficiency you have to bring the construction and the manufacturing teams together, which is what we have done. We [Arup] chose the residential sector because, in our view, if OSM is to make it then it absolutely has to be able to hold its own in housebuilding.”

So with more benchmark projects being completed, is 2004 the year of OSM? It has certainly moved up the media agenda, it has heavyweight political backing and there is a sense of momentum that, in truth, has not always been prevalent. The future might just lie on the factory floor.

Why go off site / one

The best results come from planning and co-ordinating site activity and build programmes to make efficient use of all resources, including transport, assembly labour and hired-in plant.

Why go off site / two

One of the biggest benefits of OSM is its speed. For some clients, this may not be a key factor, but there are "hidden" benefits to consider. If the time on site is reduced by six months, the savings on site preliminaries can be very significant.

Why go off site / three

It's really important that clients learn about the benefits of OSM – safer sites, better quality, less disruption, improved levels of insulation, less wastage of materials and faster programmes.

Look at other applications of OSM to see what's possible.

Don't mention the war

Noticeable by its absence in all this is the term "prefabrication", a phrase that comes clad in concrete-coated baggage. Prefabrication earned its stripes in the immediate aftermath of the Second World War, when the need for speedy resurrection of a bomb-gutted London hatched a vast swathe of prefabricated houses. The modern services that came with them far exceeded the standards of most of the British housing stock and the majority of former residents remember them with affection. Prefab subsequently became the building block for more inner-city rejuvenation in the 1960s and ultimately became synonymous with urban concrete jungles. A nadir was reached in 1966 with the infamous collapse of the Ronan Point tower block in east London, which killed four people.

Not surprisingly the prefab industry largely disappeared for another two decades. In the mid-1990s it re-emerged, mainly in the guise of pre-engineered building services, with Crown House's Wolverhampton factory pioneering a major services module for the City of London's refitted NatWest Tower. It was also reintroduced piecemeal through specific solutions such as bathroom pods for hotels.

"OSM's prominence has come in waves," reflects Arup's Miles. "If you look at the background to OSM then historically there have always been special circumstances and a major government push behind it. We saw that after the war, during the slum clearing of the 1950s and 1960s and again with these major build programmes. The momentum for OSM has been building for four or five years now and I wonder whether we are coming close to the end of this latest window of opportunity. If OSM cannot prove in the next 12 to 18 months that it can be as cheap as traditional build then in my view it may have missed its chance."

Offsite supplement Oct 2004