How to Frame a Putter Shed Roof

Measure the front and back walls with a tape measure to determine a pitch for the roof; a 7-foot back wall and an 8 1/2-foot front wall has a rise of 18 inches. Figure the pitch by matching the shed width, say 6 feet, and the rise; in this example it is 3 inches per foot or what is called a 3/12 pitch.

Figure the length of rafter needed to connect the front and back walls and support the roof, using the "length of common rafter" table on the wide blade of a framing square. Look under the 3-inch mark, for the pitch; it should show 12.87, meaning the rafter must be 12.87 inches for every foot of run, or distance from wall to wall. Multiply that differential by the shed depth, 6 feet; 74.22. Add 18 inches for an overhang over the front wall and 6 inches for a rear-wall overhang for a total of 92.22. Round that to 7 feet 7 inches.

Cut six rafters to the length determined in Step 2 with a chainsaw. Mark "birdsmouth" triangles to fit the rafter on top of both wall caps. Set a board on top of the walls and mark the bearing points or spots at which it touches the wall board edges.

Lay out 1-by-3 1/2-inch triangles at those points, with the 1-inch vertical side to fit against the inside edges of the two walls and a 3 1/2-inch slope to fit on top of the wall. Mark rafter ends by putting the point of the square at the bottom of one end of the board with 3-inch mark on the tongue and 12-inch mark on the blade at the top of the board for the front end. Reverse the procedure for a cut on the back end.

Test that pattern on the walls to verify the angles. Cut five rafters to that pattern. Nail the rafters to the caps on both walls with 16d framing nails, spaced 24 inches apart. Put two nails on one side and one on the other on both ends of all rafters.

Cover the rafters with 1/2-inch oriented strand board decking. Nail it to the rafters with 8d galvanized nails. Nail on full 4-by-8-foot sheets and use a circular saw to trim the excess at the edges; leave an extra 6 inches on each side. Install front and back 1-by-4-inch facing boards on the ends of the rafters, 11 feet long to extend 6 inches beyond each side wall. Fasten these with two framing nails into each rafter end. Connect these ends with 1-by-4-inch facing cut on the ends to the rafter angles. Nail the side boards through the end boards.