Topic: Roof Framing

Octagon Roof Hip Drop Amount.

When framing a gazabo roof you can use this process on a CM calculator to find the amount of drop for each hip so the jack-rafters plan in correctly with the hip rafter. The example below is for a roof with an 8" rise.

Enter [on/c] [on/c]
Enter 67.5 [Pitch] (This is 1/2 the plan angle of and octagon corner)
Enter .75 [Inch] [Rise] (Whatever half the thickness of the hip is.)
Press [Run] Returns .3106
Press [=] [Run]
Press [x] [8] [= ] Returns 2.485281 (8 which is the roof rise)
Press [÷] [13] [= ] Returns .1912 (13 which is the hip run)
Press [Conv] [Inch] returns 3/16"