There are as many base feet of 17" as there are number of feet in half the width of the building. (See rules for base of rafters, fig. 21.) To obtain the length of a hip rafter, lay the square on the rafter at 17" base and the rise of the common rafter as many successive times as there are base feet in the hip rafter. (Fig. 37.) Mark on the base for the plate cut and on the rise for the plumb cut to meet the ridge. (Fig. 40.) For the angular cut to meet the ridge, take the number of inches in the hypotenuse of the base and rise of the hip rafter in one base foot (fig. 38), using this hypotenuse to mark on instead of the rise (fig. 39), with the base (17") on the square and mark on the length of the hypotenuse for the angular cut. (Fig. 40.) Take 1/2 of the base and hypotenuse where required.

Hip Rafter 39

Fig.37

Hip Rafter 40

Fig. 38

Hip Rafter 41

Fig. 39

Hip Rafter 42

Fig. 40

This rule is reliable in any pitch. At the base of the hip rafter cut off 3/8" to lower the corners to line of comon and jack rafters, or saw 3/4" or more, depending on pitch of roof, plumb down across the corner. (See fig. 41.)

Hip Rafter 43

Fig. 41

Hip Rafter 44

Fig. 42