Robert Clark of Fusion Building Systems explains the benefits of offsite manufacturing, explaining how time-saving but high-performance SIPs could help ease the UK’s housing shortage
The UK is suffering from a lack of housing, with even the Government citing a ‘broken housing market’ in its heavily anticipated White Paper last month. Encouragingly however, the Paper assured a commitment to supporting the development of ‘modern methods of construction.’ Volume housebuilders are now beginning to incorporate offsite into their future plans, many seeing it as a step change in their whole supply chain process.
Of course, there’s nothing new about offsite manufacturing (OSM), and for that matter, structural insulated panels (SIPs). Development of SIPs systems dates back to the 1940s, although the industry didn’t really gain momentum until the 1970s. The products available now however can deliver a U-value of 0.2 W/m2K (which alone surpasses Building Regulations) or with further insulation installed during construction on site, up to 0.12 W/m2K or 0.15 W/m2K. Achieving such performance of course depends on the choice of product and the building fabric.
Essentially, there are two options for OSM: panelised, with a choice of light gauge steel (LGS) or timber; and volumetric, or modular as the Government is terming it. Depending on which you choose, the insulation levels can vary enormously. Some timber frame structures will be pre-insulated, others will be open, and for LGS, some will be loose-filled, while some specialised systems even offer fully wrapped panels.
If you opt for an LGS frame, then ensuring it’s fully wrapped is pretty important if you’re to avoid issues with cold bridging in achieving the required U-values. You can of course insulate the cavity on site using bead, wool or slab, but if the steel’s been fully wrapped offsite in the first place, this problem is eliminated.
Supply chain integration
Addressing insulation is only scratching the surface of what should be included in the OSM process. It all comes down to early supply chain integration. The specification and positioning of doors and windows, the routing of M&E services, H&V systems and communications connections all need to be agreed early on. Even the positioning of brick ties or clad anchorage points must be agreed on. These should all be worked into the building’s design and form part of the manufacturing process of the individual cassettes or panels for the building. Once on site, the (pre-insulated) frames can be erected in a matter of days and all other elements slotted seamlessly into their allotted positions. The cost and time saving benefits of this approach are clear, as is the reduced reliance on skilled site labour – another issue affecting the UK’s housing crisis.
Putting this into practice, Fusion started working with Barratt Developments in 2015 as it began its evaluation for offsite supply chain partners. As part of this process, a trial project was run for the design, specification, manufacture and erection of nine residential properties at its Swanbourne Park development in Angmering, West Sussex.
The company successfully completed the project using a framework which had been manufactured using its patented technology. The trial required the integration of teams at all levels from both businesses, with the need to adapt Barratt’s existing housing models to incorporate the new system. The erection process took just nine days, with only five men on site.
The trial was one of the smallest jobs the company has completed in its 16-year history, but by successfully demonstrating how a supply chain can be adapted to suit a much faster, safer and more cost-effective method of building, it will potentially be its most significant.
In 2015 The Housing Forum issued a report, More Homes Through Manufacture, exploring how modern methods of construction could deliver more, better quality homes. In his closing remarks, Working Group chair Jim Martin commented on the numerous advantages OSM can bring to housebuilding in the UK, including the “Improved energy performance of buildings through enhanced specification and controlled factory processes.”
The opportunities presented by OSM are vast, and with proper integration into the housebuilding supply chain, could go a significant way to towards reducing the UK’s critical housing shortage.
Robert Clark is head of business development at Fusion Building Systems