TRUSSED RAFTERS SPEED CONCENTRIC ROOF CONSTRUCTION FOR WV4

Harlow Timber Systems undertook the £36K contract for Bellway Homes at its iconic WV4 development on a supply-only basis. The site created 55, mainly two-bedroom, apartments and is dominated by the curved main four-storey structure, with its metal decked roof and central courtyard.

The decision to use trussed rafters was taken after careful evaluation of three different design options. The two main alternatives would have involved substantial cold rolled steelwork or engineered timber I-beams. The latter would have needed huge bottom flanges to achieve the spans, and required the installation of a suspended ceiling system at considerable additional cost, while the timber lattice trusses could have plasterboard soffits secured beneath them in the normal manner.

The lattice trusses were quickly installed to give a safe working platform on which a covering of OSB boards was laid at the required falls; this is covered in the standing seam metal sheeting.

Harlow fabricated hundreds of different sizes of trusses up to 12 metres in length; many of them are spandrel panels necessary to form party wall divisions within the roof space or to enclose plant such as lift rooms.

For more information on the Trussed Rafter Association, please call Susan Farrow on 01246 230 036, or visit www.tra.org.uk.

A spokesperson for Bellway Homes explained how, in conjunction with Harlow, the housebuilder had refined the original design concepts of the architectural master planner to address issues of buildability.