Corus’s light steel framing system, SureBuild, is based on 75 mm deep galvanised steel C sections that are prefabricated into wall frames to match the configuration of the building. The wall frames include integral bracing and are easily man-handled on site. The floor joists are a 150 mm deep ‘sigma’ section that are supported on a Z section element attached to the wall panels. The construction is a ‘warm frame’ by use of Celotex R insulation board attached externally to the wall frames. Fire resisting board is used internally. Special features of the method of construction are the ability to create an ‘open-roof’ system for additional habitable space, and the use of various forms of ground floor and foundation systems to match the ground conditions. The construction can achieve a high level of thermal insulation. All the components, and complete assemblies have been subject to extensive testing at Corus’s Welsh Technology Centre, culminating in full-scale load tests on an unclad and clad 2-storey house. The system has an Agrément certificate, and there is now considerable experience on its use and in-service performance. A number of major house builders, including Taywood Homes, use the SureBuild system. Construction costs are competitive with conventional forms of house construction, but with further advantages offered by light steel framing include rapid construction, dimensional accuracy, long life, long span capabilities and future adaptability. The ‘open roof’ system can be provided at nominal additional cost. A further major demonstration project on the use of light steel framing using the SureBuild system is underway at Oxford Brookes University.
Like most lightweight steel framing systems, it combines the potential for fast-track construction with a unique degree of dimensional stability. The building time of an average house is cut by 6 to 10 weeks compared with conventional methods of construction.
Based on a system of 75mm deep galvanised steel framing members, each configuration is individually designed for a given house shell. Unlike most other manufacturers, BSF offers a turnkey service: design, engineering, manufacture and erection are all part of the package, right up to sheathing in Celotex R insulation.
- Contract period cut by 6 to 8 weeks compared with conventional construction.
- Economical use of cold-formed steel sections in panel construction.
- Pre-engineered components offer excellent dimensional accuracy.
- Open roof system can be included at nominal extra cost.
- Adaptable to a range of building forms.
- No creep or shrinkage.
Review and Comment
Corus's lightweight framing system for the volume housing market cuts average construction time by 6 to 8 weeks and offers Taywood Houses advantages over more traditional techniques.
While volume house-builders face more and more demanding regulations, market conditions stubbornly refuse to improve. In this context, the ease with which light steel framed houses can meet new thermal and technical standards is making them look increasingly attractive.
SureBuild is a system developed by Corus formerly British Steel Framing (BSF) specifically for this sector of the market.
The use of steel framing was not the only innovation applied on this job. For instance the roof was assembled at ground level and lifted into place in one piece. "It was an exercise in fast-tracking," says BSF Technical Manager Graham Webb. "We found that as soon as we gave possession of the bare frame, the plumber and the electrician were very keen on keeping the job moving."
Site workers commented on how the fixing of the stained softwood windows to the steel subframe before the brickwork was laid made their work much easier. The construction period was only 8 weeks to completion of the building, and the steel frame took only 3 days to erect.
The party wall, which is in fact a pair of walls separated by a 100mm gap, was tested to give a sound reduction of 65 dB.
Taywood’s verdict on the job was positive. They have recently completed a 34-house scheme in Southampton using the Surebuild system, and are partners with BSF and The Steel Construction Institute in the construction of a Demonstration Building at Oxford Brookes University.