BS 5268-3:2006

Committees responsible
Foreword
Introduction
1 Scope
2 Normative references
3 Terms, definitions and symbols
4 Assessment of structural adequacy
5 Materials
   5.1 Timber
   5.2 Plywood
   5.3 Fasteners
   5.4 Adhesives
   5.5 Preservative treatment
6 Trussed rafter design
   6.1 General
   6.2 Limitations
   6.3 Permissible stresses, fastener loads and nail
        spacing
   6.4 Loads
   6.5 Method of design
7 Roof design
   7.1 Design responsibilities
   7.2 Overall stability
   7.3 Wall plates
   7.4 Plasterboard ceilings
   7.5 Water tanks
   7.6 Hatch, chimney and other openings
   7.7 Roof environment
8 Fabrication
   8.1 General
   8.2 Assembly
   8.3 Marking
9 Handling, storage and erection
   9.1 Handling and transportation
   9.2 Storage
   9.3 Erection
   9.4 Modification and repairs
10 Load testing
   10.1 General
   10.2 Testing authority
   10.3 Information required by the testing authority
   10.4 Quality and fabrication of trussed rafters for test
   10.5 Tests on similar configurations
   10.6 Acceptance
   10.7 Use of tested trussed rafters
11 Exchange of information
   11.1 Information required by the trussed rafter designer
        from the building designer
   11.2 Information to be provided by the trussed rafter
        designer to the building designer
Annex A (normative) - Roof bracing
Annex B (normative) - Permissible spans
Bibliography

Gives guidance on the design, fabrication and use of trussed rafters for roofs in service classes 1 and 2 as defined in 3.1 and 3.2. Guidance is provided on structural analysis methods, engineering design criteria and design by testing. Performance requirements for roof bracing are given, together with standard bracing arrangements for domestic scale roofs. Production requirements are also given for truss manufacture, along with guidance on their handling, storage and erection. Maximum spans for two common truss configurations for a range of member sizes and roof pitches are given, based on extensive tests.