BSI Business Information has revised the industry-wide BS 5268-3:200 structural use of timber code of practice for truss rafter roofs.

The standard covers the design, fabrication and use of truss rafters for roofs. The BSI said that for the purposes of the standard, truss rafters are assumed to be made from timber members of the same thickness fastened together by metal plate fasteners or plywood gussets.

The standard provides recommendations on the strength grades of timber used in the fabrication of rafters and other critical design issues. Guidance on the handling, storage and installation of fabricated rafters is also given, and information to be exchanged between the truss rafter designer and the building designer is also listed.

Guidance is provided on structural analysis methods; design by testing; standard bracing arrangements for domestic scale roofs; peformance requirements for roof bracing; engineering design criteria and production requirements for truss manufacture.