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Erection Procedure
The builder should consider, in conjunction with the Building Designer, the erection procedures to be used and the provision of temporary bracing, rigging
and any other specialised equipment required to erect the trusses safely and without damage, in accordance with the design requirements and having due regard to possible windy conditions.

Permanent bracing should be of minimum size 22 x 97mm free of major defects and fixed with two 3.35 x 65mm galvanised round wire nails at each crossover.
The following procedure is suggested for most domestic size roofs.

1. - Mark the position of each truss along both wallplates.

2. - Erect the first truss (truss A in figure 94a) at the point which will coincide with the uppermost point of the diagonal brace F when it is installed later. Use
the temporary raking braces B fixed to the rafter members and the wallplates to hold this truss in the correct position, straight and vertical. For clarity, only on raking brace is shown in the figure but they should be fixed to both rafter members and be of
sufficient length to maintain the truss in position, during the erection of the remaining trusses.
3. - Erect truss C and brace back to A with temporary battens D at suitable intervals along the rafter and ceiling tie members. Repeat this procedure until the last truss E is erected.

4. - Fix the permanent diagonal braces F ensuring that each top end is as high up the last trussed rafter A as is possible and that each bottom-end extends over the wallplate to which it should be fixed. For clarity, only one permanent brace is shown in the figure, but they should be installed on both sides of the roof.

5. - Fix the longitudinal members G, making sure that the ceiling ties are accurately spaced at the correct centres.

6. - Fix all remaining longitudinal, diagonal and chevron bracing required on the internal members of the trusses as specified.

7. - Additional trusses may be erected by temporarily 'bracing-off' the completed end.
Immediately prior to the fixing of the permanent bracing and the tiling battens or sarking, all trussed rafters should be checked for straightness and
vertical alignment. Whilst every effort should be made to erect trusses as near vertical as possible, the maximum deviations from the vertical shown in the
following table may be permitted.
Maximum deviation from vertical
After erection, a maximum bow of 10mm may be permitted in any trussed rafter provided that it is adequately secured in the complete roof to prevent
the bow from increasing. For rafter members, this maximum bow is measured from a line between the apex and the eaves joint.