There is no Plan B

8 June 2012

Don't listen to the naysayers, the arguments for offsite construction are too compelling for the sector to bow to critics, says Richard Ogden.

There are days when I have to conclude that I am living in a parallel universe. Apparently quite normal and usually very intelligent people come up to me at an event or at a meeting to let me know that while they personally understand and support the business case for the construction industry to shift away from building on site to assembling off site, it will never catch on big time.

Often these conversations will take place within sight of a major construction project where even the casual observer can see for themselves that the building is being assembled from large and usually high-value components manufactured and tested in a factory and delivered just in time to an often very congested site for immediate assembly. But despite this evidence, the negatives keep coming.

Another argument is the number of high-profile business failures within the UK offsite manufacturing sector. A clear sign that the offsite market is in decline I am told, or evidence that the market is too small to sustain the capital investment needed to operate a modern offsite manufacturing facility, that manufacturers can’t win enough business to achieve the economies of scale needed to support the investment.

We read about these examples in the technical press and no doubt many will feel that their views on offsite have been further vindicated. It is certainly a tragedy when companies that manufacture great products go to the wall, but what I suggest people are losing sight of is the fact that the number of failures is relatively few with far greater numbers of traditional contractors also going bust.

I am not sure what is so emotive about offsite construction. It is not new and it is not alien. It patently can improve levels of productivity on site and help to fast-track the building process. It demonstrably leads to reduction in waste, reworking and delivering right-first-time quality. The problems that loomed large in medium/high-rise housing systems of the 60s and 70s arose as a result of poor detailing, poor management and poor site practice. Today we are as far removed from those mistakes as modern UK manufactured cars are from those of the 60s and 70s.

I’m sure that there was a time when prefabricated steelwork was regarded as something new and therefore risky. Ditto fully glazed cladding systems, factory assembled building services, precast concrete columns and flooring systems and so on. My conclusion is that there are many people in this industry who intuitively regard anything new and innovative as risky and best avoided if at all possible. But outside of the working environment we almost all welcome innovation in consumer electronics or in other sectors. So why does innovation in construction just not do it for us?

Those people who have serious doubts about the role of offsite construction methods may be at risk of confusing common practice for house building in the UK and increasingly common practice for other construction markets. I would absolutely agree with them that house building in the UK has grown to be fundamentally different to mainstream construction and is subject to its own set of business drivers.

It is very easy to switch traditional labour on and off to meet market demand for what are generally small-scale developments. It is also relatively easy to squeeze trade contractor margins until the pips squeak. A great strategy if your aim is simply to keep construction costs as low as possible, but a dead-end strategy if your ambition is to generate sufficient margin to invest in innovation to increase productivity on site and to build and then maintain the quality of homes that we all want. I shall be interested to see just how long current practices last when government targets for low carbon construction and the advent of BIM starts to really bite on construction projects.

Despite all the negative comments, BuildOffsite will continue to drive its agenda to help make the case for the increased use of offsite solutions. I am rather pleased that we are experiencing a degree of push back from certain quarters, it means that we are getting a reaction.

Richard Ogden is chairman of membership organisation BuildOffsite

Behind the launch: RockShell

Launched in February, the RockShell system comprises hybrid structural insulated panels for the construction of low-rise housing. The panels consist of load-bearing steel I-Profiles, dense Rockwool insulation and an interior lining of oriented strand board.

By using steel-framed modules instead of timber-framed, UK business manager Matt Bromley says that the units become much thinner and easier to fill with insulation. In turn, this means that air voids, air-tightness and cold bridging is less of a problem. “We start with the steel profile then slot the 250mm thick RockWool element in.

It wraps around the steel to eradicate cold bridging, and we end up with an insulated load-bearing envelope.”

The system was designed to address the energy gap between designed and as-built thermal performance in homes. Its walls are designed to achieve a U-value of 0.143 as standard, but the company says it can achieve better results if required.

The system is designed to be easy to erect on site. At a recent demonstration project with developer Lioncourt Homes in Gloucester, a Passivhaus certified four-bedroom house was built in just 10 days. “Most of the system can be put up using a cordless drill. With Lioncourt we used three carpenters who had no experience of the system, but they picked it up very quickly,” said Bromley.

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