Split Pitch Roof Framing

Rafter layout with a framing square.

Split pitch roof framing.

At the low end of the valley the subfascias of the two roofs are mitered with a block filling in the roof framing. Explore framing complexities that result when roofs of two different pitches intersect. Position the square with both the 8 inch on the outside edge of the tongue and the 12 inch on the blade on the upper edge of the board. Learn more about off angle roof framing.

The minimum roof pitch is 1 8 inch rise per foot of span. It is also easier to insulate a roof with a greater pitch. This example is for a roof with an 8 12 pitch. Sheathing blocking is added along the valley and the sheathing pieced in for both roof planes.

1 8 pitch is given so 24 x 1 8 equals 3 or unit of rise in inches. Figure 2 2 roof framing terms. Keep in mind the rafter approach can take several days and up to 3 weeks to complete a suitable frame. If the pitch were 24 12 for example you would remove about 57 of the width on a 2x6 rafter in his book roof framing pages 35 36 marshall gross suggests that as a general rule don t remove more than a third of the stock.

If the unit of rise in inches is 3 then the cut is the unit of rise and the unit of run 12 inches or 3 12. The greater the roof s pitch the better it will shed snow ice and rain. Position the square at the end of the rafter board with the tongue on your left and facing away from you. Line length is the hyptenuse of the triangle whose.

Repeat the process on the adjacent pitch side of the hip rafter using 5 3 4 12 on the framing square for a miter angle of 25 64298. The total rise is 12 inches or 1 foot and the span is 4 feet so the pitch would be 1 4 or a quarter pitch roof. To transition the eaves the horizontal fascia extends to the last rafter tail and a vertical return finishes the transition.