SterlingOSB has been chosen as the ideal engineered wood-based panels for a new generation of prefab housing. Architect Iain Bruce and engineer Bill Graham have developed a housing unit entirely constructed of SterlingOSB because of its natural strength characteristics and cost-effectiveness.

Iain explained the concept: “This technology allows the units to be purpose-built in a factory and transported to the site. They can then be assembled in various groupings like full-scale Lego. Other prefabs rely on sections being bolted together and are dependent on weather tight joins being properly sealed on site. Our units are not vulnerable to this procedure.”

As the units typically measure 12 metres long, 4.3m wide and 2.8m high, they need to be classified as a wide load in order to transport them from factory to site. This would incur extra costs. However, Iain and Bill have developed a special jig which allows the units to be turned on their shorter side for loading onto trucks. This means that they are no longer classified as wide loads.

To rotate a unit of this size over 90º presented its own problems. Iain needed a material that could withstand the considerable stresses produced by this procedure. “The engineering design of the duocoque structure is crucial as the roll-over procedure puts severe stress on the walls and end panels. However SterlingOSB’s high strength characteristics makes it the ideal material for the stressed-skin structure,” explained Iain.

Tests were carried out with Norbord on an eight tonne housing unit which was fully fitted out with partition walls, kitchen units and bathroom fixtures. It was subjected to eight rotations and reversals which resulted in no signs of cracking of either the internal plasterboard lining or glazing. The units also have excellent thermal insulation properties which complement their environmentally friendly credentials. Iain has produced a 3D interactive CD of the units and is in discussion with housing associations considering offsite manufacture.