Trussed rafters shall be erected in accordance with BS 5268: Part 3, Clause 9.3 and Trussed Rafter Association (TRA) site installation guide: • Do not modify trusses without approval. • Do not use damaged trusses. • Truss clips and bottom chords of standard trusses and rafters of raised tie trusses shall bear fully on wall plates. Bottom chords of standard trusses shall not be fixed to internal walls until roofing is complete and cisterns are installed and filled. 2.6 Jointing and Fixing 2.6.1 Bolted Joints Minimum bolt spacing for bolted joints shall comply with BS 5268: Part 2, Table 81. Holes for bolts shall be located accurately and drilled to diameters as close as practical to the nominal bolt diameter and not more than 2 mm larger. Bolt shall be tightened so that washers just bite the surface of the timber. At least one complete thread shall protrude from the nut. Bolts shall be tightened as necessary at agreed regular intervals up to completion. Washers shall be placed under bolt heads and nuts that would otherwise bear directly on timber. Spring washers shall only be used in locations which will be hidden or inaccessible in the completed building. Washers shall be of a material and finish to match bolts. When seated directly on timber surfaces, unless specified otherwise, diameter/side dimensions shall be not less than 3 times bolt diameter, and thickness not less than 0.25 times bolt diameter. Bolted joints with connectors shall comply with the following requirements: • • Centres of bolt holes: not more than 2 mm from positions shown on drawings. • During assembly do not crush timber, deform washers or overstress bolts. • 2.6.2 Where not otherwise shown, spacing, end and edge distances to be not less than Standard values to BS 5268: Part 2, Section 6. Framing anchors shall be galvanized or sherardized square twist nails sized and spaced as recommended by anchor manufacturer. Glued Joints Where relevant, manufacturer's confirmation shall be obtained that adhesive is compatible with preservative/ fire retardant treatment. Glued structural components shall be fabricated to BS 6446 in clean, controlled workshop conditions. 2.6.2.1 Bonded and Expansion Anchors Instructions shall be obtained if specified spacing or edge distance cannot be achieved. Page 10