Off-site construction has come a long way since the 1960s - but particularly in the past 10 years, as these case studies demonstrate …
There can be few more telling remarks about the way off-site construction (OSC) is still viewed in some quarters than that expressed by Darren Richards, managing director of Mtech Group, the company cited as championing the modern-day OSC technology revolution.
Richards says: "Some people won't forget what happened one day in 1968, but we have moved on since then. People didn't stop flying just because of one air crash."
The event he refers to is the partial collapse of Ronan Point, a high-rise block in Newham, east London. Four residents were killed following a gas explosion that tore away one corner of the 22-storey precast concrete tower, which was constructed using the Taylor Woodrow Anglia building system.
That morning in May was to hold back off-site construction for decades, with professionals and clients wary of prefabrication and a public that was highly sceptical about anything other than traditional building techniques. But things have changed and the past decade has seen significant strides in OSC technology innovation.
Charles Westbrook, R&D director of Mtech, says: "Many other 1960s prefabrication technologies were perceived as the worst example of OSC. But many have probably at least doubled their design life. If we got the same out of our cars, we would think they were wonderful."
These success stories have largely gone unsung, but there are now signs that attitudes towards OSC are changing. Over the past decade interest has been rekindled, with retailers and commercial developers leading the way. Housing associations, housebuilders, the prison service, educational establishments and healthcare providers are also recognising the huge potential of using OSC.
Even so, OSC is still a fledgling process, as Richard Ogden, chairman of Buildoffsite, the body charged with revolutionising construction, explains: "The percentage of off-site construction is very low - it's £2.2bn out of a total industry output of £106bn. The growth potential is vast. The ODPM is promoting modern methods of construction for housing, but think about the rest of construction - the commercial rump, the retail rump, the civil infrastructure, MoD and so on. There are great swathes of opportunity.
We still have a long way to go but the opportunities that lie ahead are massive
Darren Richards, Mtech Group
"Just consider all the mechanical and electrical services that can be built off-site and plugged into a building. For a heavily serviced building that can be over 40% of the total cost, and yet we will spend hours concentrating on the architecture. Architecture is very important, but look at the figures - over 80% of the cost of the building is not visible."
Darren Richards agrees. "When you consider OSC's contribution to the construction industry is less than 2%, you realise we still have a long way to go, but the opportunities that lie ahead are massive. It has taken the industry 10 years just to get to that 2%. Buildoffsite is trying to promote tenfold growth by 2020, which we think is achievable, provided certain things happen within the industry such as investment, knowledge transfer and R&D. What we can do in the next 10 years should far outweigh what we have done in the past 10 years."
Last year, Mtech in partnership with Building, helped compile the second Off-site Directory, which listed firms engaged in OSC. Richards admits surprise at the number of companies, about 500, that were unearthed during the exercise. "It has been a hard industry to compile information about. The Off-site Directory put that into the public domain and made people realise the broad spectrum of technologies that exist and how many companies are involved."
Even so, he says, Mtech can understand some clients' reluctance to embrace OSC. He observes: "The off-site industry has to take a lot of responsibility for that. We need to satisfy a lot of the very valid questions the industry is asking about performance over a 60-year life span. Some of the technology is not even 10 years old, let alone 60 years old."
Another issue is changing clients' perceptions. Richards says: "If you go into the education sector, they associate OSC with temporary classrooms. We need the right terminology to say this is different - it is not prefab, but something using modern materials and processes."
Martin Goss, Mtech's group technical director, says the method of procurement has a major influence on whether or not innovation is taken up. He explains: "Innovation will only work within a certain type of procurement and, for me, PFI is disappointing because you would have thought it would have bred innovation. Here is the chance to look at things differently and yet most PFI projects have been steadfastly traditional.
The method of procurement on a project has a major
influence on whether or not innovation is taken up
Martin Goss, Mtech Group
"The major controller of PFI activity is the operator, who is even more concerned in many respects than the builder. So you have two sets of people making decisions on how things will be built, and innovation suffers."
Even though there are obvious growing pains within the OSC industry, this hasn't stopped innovators such as retailers Tesco, Asda, and McDonald's, hotel chains such as Travelodge and Accor, developers such as Stanhope and Canary Wharf and key clients such as BAA.
Richards says: "If you look at the sectors that have progressed rapidly over the past 10 years, you could track it to the retail and commercial markets. They have driven OSC for business reasons, outside of issues such as skills shortages and quality. Their logic is about return on capital employed."
Another catalyst over the past decade was the publication of Sir John Egan's Rethinking Construction report in June 1998. Goss says: "It made people ask: ‘What is off-site construction'?"
Richards credits the Movement for Innovation (M4i) for helping create a climate for change through a series of OSC conferences, held between 2000 and 2002 and organised by Mtech's M4i joint venture Manufacturing the Future. Richards remarks:
"People went away with the confidence to light the touch paper - that is why we have seen a lot more change in the past five years."
This is going to blow John Prescott’s £60,000 house out of the water
Wayne Morgan, Elements Europe
"This is going to blow John Prescott's £60,000 house out of the water." So says Wayne Morgan, managing director of Elements Europe, of his firm's bathroom and kitchen pod system, Copod, developed on their behalf by Mtech Group.
The system consists of a pod with the kitchen and bathroom arranged back-to-back with the 300 mm space between their two back walls containing all the services. The pods can be stacked on top of one another and have an interconnecting vertical duct that acts as the umbilical chord for all the services. The beauty of the system is that it eliminates all first-fix and almost all of the second-fix operations that are required in conventional homes for heat, light and power.
Morgan believes Copods will dramatically cut build time and says it is not inconceivable that a one-bedroom apartment unit could be completed in only four weeks.
The concept is geared around the power sockets and lighting switches being installed on the walls of the centrally located pod. If additional sockets and switches are required elsewhere, the builder can install these and then simply plug into a ready-made connection within the pod.
Each Copod weighs around 1.7 tonnes. Lightweight steel frames are used for the walls, which are fixed to a welded steel subframe to provide rigidity during manufacture, transportation and installation. Cranes are only required to offload the Copods, thereafter skids are used to position a unit inside the house. They can be positioned after the shell of a dwelling has been constructed as long as there is an opening the size of a normal patio door to gain entry. For two-storey or multistorey housing, the pods can be supplied with an integral staircase to further cut down work on site.
Pod production is due to start before the beginning of May at a purpose-built factory in Oswestry, Shropshire, with a capacity of manufacturing 1000 Copods plus 2500 single pods - bathrooms or kitchens - a year. Morgan says the facility is intended solely for the housing market, particularly affordable one-to-three-bedroom housing.
The venture is the brainchild of JR Pickstock, a regional builder that constructs around 200 houses a year. Pickstock founded Elements Europe not only to supply pods for its own workload but also to sell them to housing associations and other builders. It has designed nine housetypes around the pods and will offer these to fellow housebuilders.
Morgan says: "We went to Mtech because they are the leaders in off-site construction. Together we worked on design and all the systems to develop a cutting-edge solution."
We went to Mtech because they are the leaders in off-site construction
Wayne Morgan, Elements Europe
He says that going from concept to building the prototype took less than six months and involved a lot of interaction between Elements Europe and Mtech. Throughout the process a prime consideration was ensuring the design was suitable for the manufacturing techniques available.
A Copod built to the highest spec should cost about £14,000. This, says Morgan, includes absolutely everything such as oven, fridge-freezer, boiler, ventilation equipment even a plasma screen fitted to the end panel that doubles as a wall to the living or dining area.
The concept appears to have caught the imagination of housebuilders and Morgan says in one week alone, an enquiry was received for 1150 pods.
The product will be launched formally at Interbuild.
European Timber Systems
David Holmes has spent half a century in construction, including a spell as chairman and chief executive of John Lawrence, then Scotland's largest independent house builder. He started building timber-framed houses in the 1970s, but only decided to enter the manufacturing side of the industry a little more than two years ago when co-founding European Timber Systems (ETS).
What probably would have taken us three years turned into six months
David Holmes, European Timber Systems
The former chairman of Glasgow Rangers FC says: "We wanted to look at creating the next generation of timber frames by bringing in new manufacturing technology."
Holmes says the plan was to develop revolutionary concepts in timber-framed walls, floor cassettes and roof panels before moving on to develop kitchen and bathroom pods.
To turn the plans into reality, Mtech Group was called upon to advise on all aspects of strategy, design, procurement, manufacturing, and help commission a 5100 m2 factory in East Kilbride. Darren Richards, Mtech's managing director, describes the resulting creation, marketed as "Innova", as "a complete housebuilding system different to most timber-frame systems that simply emulate a conventional house structure".
Richards says Innova takes OSC to a realm far beyond systems provided by suppliers just offering a timber frame. All of ETS's wall, floor and roof units can be supplied as closed frames that are pre-wired or have conduits through which the services can be fed.
Holmes says a vital ingredient in getting Innova so quickly on to the market was the interest shown by Gladedale Holdings, the umbrella company for several house builders including Gladedale Homes, Bett Homes, Furlong Homes, Furlong City and Manor Kingdom. ETS and Mtech made a presentation to Gladedale that led to the firm acquiring an 80% stake in ETS in January 2005 and provided the £2m needed to buy machinery and get the East Kilbride factory into production.
The good thing about automation is that machines don’t need a rest
David Holmes, European Timber Systems
By July 2005, the factory had been fully commissioned. Holmes says: "What probably would have taken us three years turned into six months with Mtech Group and Gladedale on board."
Holmes claims Innova has lessened the average time to build a typical Gladedale house from 16-20 weeks to 12 weeks.
The factory's current capacity is 1500-1700 units a year; working on a one-shift production cycle. All current production is for use within the Gladedale group, which builds about 5000 houses per year, from £1m mansions to affordable housing. Holmes, who is on Gladedale's board as well as chairman of ETS, says raising capacity at the factory wouldn't be hard. "The good thing about automation is the machines don't need a rest."
He says Gladedale is also looking at building another factory to service the group's activities further south.
Richards says: "Rolling out Innova across the Gladedale group is the next challenge. We are working to engage their regional businesses and to develop supply-chain processes to get the best out of the technology developed."
Most of housing contractor Hill Partnerships' projects involve off-site construction and, not surprisingly, managing director Andy Hill is completely sold on the idea. Hill has seen his seven-year-old company blossom on the back of OSC to the point that it now employs more than 100 people and he expects turnover to hit £65m in the coming year - an increase of more than 60% on last year's workload.
Hill's passion for OSC is evident when he describes a recent NHS project to provide 124-bed accommodation facilities for key workers in central London. "It took 34 weeks to construct. If it had been built traditionally, I would have been very pleased to do it in 65 weeks."
Slashing construction time by nearly half was achieved by using volumetric modules for the bedroom and en-suite bathroom areas, which were fully finished right down to the carpets. A panellised system was used for the kitchens and corridors, which were then treated to the finishing touches on site.
We always look at de-risking as much of the process as possible
Andy Hill, Hill Partnerships
Hill says choosing OSC was a "cost-neutral" solution and the project was completed for less than £1100/m2 - an impressive feat for building on a confined site in central London.
Hill adds: "What drives us towards a volumetric solution are tight sites. Provided we can get a crane on site or close the road, we can then erect the building very quickly. We also carry less risk on labour and materials because we have subcontracted the large elements to off-site suppliers. We always look at de-risking as much of the process as possible."
In most cases, Hill Partnerships is engaged before a project has gained planning approval. "This way we have the opportunity right at the start to influence decisions and make sure the buildings are designed to suit a particular methodology," says Hill.
From its inception, the company has employed Mtech Group as a consultant under a rolling retainer arrangement. Hill says: "Mtech gets involved right at the beginning and helps us decide what OSC solution is best suited for that job. If we are using a manufacturer for the first time, Mtech will be involved in the assessment of that particular supplier and carry out a technical critique of the system.
"We also use them to help us manage the interfaces between different OSC solutions. We have our own technical coordinators, but they have general skills. So when we get into something quite specific relating to OSC, we get Mtech to detail the interfaces. I use them as a risk management consultant."
It took 34 weeks to construct. With a traditional build, I’d have been happy with 65
Andy Hill, Hill Partnerships
Hill says some suppliers were sceptical about having a consultant look at their manufacturing processes for fear that their ideas would be disseminated to other suppliers. "I think a lot of them are used to people telling them: ‘I'll have one of those, you deliver, and I'm not interested until it gets on site'. We don't operate like that - we want to manage the process because for every hour we spend solving the problems pre-site, we will save 10 hours on site."
For three decades after it was founded in 1971, Swift Horsman operated in the traditional world of washroom construction where a series of trades vied for space on site. Then, four years ago, its transition from on site to off site began.
Managing director Gary Saunders attributes this to two events. One was developer Stanhope urging the company to "make things better". The second was attending a conference on off-site construction in Birmingham, organised by Mtech Group. "The conference made us think seriously about OSC and what we should be doing to improve our business. We called in Mtech and had a brainstorming session to develop ideas to re-engineer the process. At this stage, we had no preconceived ideas of the right way forward and presented Mtech with a blank sheet of paper."
There followed a thorough appraisal of everything: materials; how elements such as wall and floor components and finishes interacted with one another; and how to integrate services such as lighting, air supply and extraction, and water supply and drainage. Also under review were the manufacturing techniques available, integrating a washroom within a building's structural frame, handling and transportation, and how the components were fitted on site.
The appraisal led Mtech to develop Podwall, a system of wall panels that can be assembled to create a volumetric box. Saunders says the system offers greater flexibility to accommodate changes than a pod design.
For sites where access conditions are restricted, a flat wall system has also been developed. Both manufacturing methods use as much standardisation as possible for the background components and materials; giving flexibility to incorporate finishes required by the architect and client.
Manufacturing is carried out either in a factory at Swift Horsman's HQ in Hertfordshire or in a sister factory at Bathgate, between Glasgow and Edinburgh. A team of about 12 designers work on AutoCAD to produce the drawings for the factories as well as electronically transferring information to and from architects, engineers and clients. Swift Horsman retains Mtech to carry out technical validations or to develop bespoke solutions as required.
Saunders says moving into OSC has created a step change in the way the firm does business. He estimates 75% of the company's turnover is earned off-site and that this year's turnover should reach £37m - up 60% on last year. "We could grow faster, but we prefer to work with a few clients and reward those that have supported and invested in us."
We called in Mtech to develop ideas to re-engineer the process
Gary Saunders, Swift Horsman
The transition to OSC has also been accompanied by a move towards offering a full fit-out service for the washrooms with the company undertaking the work previously done by other trade contractors. "The clients we work with are happy for us to do more interface work and it adds value," says Saunders.
Although Podwall is patented, Saunders says: "That hasn't deterred people from copying us, so we are always looking to update what we can offer. We regularly carry out brainstorming sessions facilitated by Mtech - we tap in to the knowledge from outside our core sector."
The clients we work with are happy for us to do more interface work and it adds value
Gary Saunders, Swift Horsman