Hip to be square

With regards to your QS quiz in the 27 May issue, if you are attempting to calculate length of hip rafter (ie the diagonal line on the diagram, sloping from corner up to ridge level), then the correct calculation should be: square root ((tan 30° x half span)2 + 2(half span)2) = 4.58 m.

A pedantic QS (Noel Hunt, Department of Transport)