Framing A Roof Of One Pitch To Another Of Different Pitch. Occasionally one must frame a roof of one pitch against a roof of another pitch. To determine the cut, if the combination tool is to be used, merely find the difference in degrees of the angles of inclination of the two rafters, and apply the tool as indicated in the tables for making any other plumb cut, Figs. 49, 60 and 73. The seat cut will be determined by the rise and run of the shed rafter in the usual manner.
Where the framing square is to be used, lay the square as in framing a plumb cut on the shed rafter, as at A, Fig. 86, taking on the tongue, the run, and on the blade the rise of the shed rafter. Next lay a second square as at B, Fig. 86, taking on the blade the rise and on the tongue the run of the rafter of the main roof, using the blade of A as a reference edge. Blade of B gives the cut.