A. Robert Randall responds: No, the scarf joint you show is not adequate to support typical roof loads on a hip or valley rafter. These members must be able to function as bending beams carrying substantial vertical loads.
Hip and valley rafters should never be compromised by such a weak splice. If splicing is required, secure a sister that runs at least four or five feet on either side of the joint. This splice should be capable of developing the full bending strength of a continuous member. Spike the overlapping piece together with plenty of well-placed nails,...
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