How to Attach Rafters to the Side of a House

Mark the wall caps and a ridge board in preparation for attaching rafters. Use a tape measure, speed square and marker to draw lines across the two outside wall caps and the ridge board. Draw the first line 1 1/2 inches in from the end of the back wall. Measure 23 1/4 inches from the end and draw another line to mark the outside edge of the second rafter. Draw lines 24 inches apart the length of the walls and ridge based on that line.

Set the first pair of rafters in place, with the triangular cut "birdsmouth" on top of the wall caps. Place the vertical part of the birdsmouth straight against the edge of the cap board and the horizontal part flat on top of the cap. Fit a rafter on each side of the roof that way.

Toenail the rafters to the cap board with 16d framing nails driven diagonally through the rafter into the cap with a hammer. Put two nails on one side and one on the other. Plumb those rafters with a level and brace them temporarily with boards nailed to the rafters and to stakes in the ground.

Erect another pair of rafters at the other end of the roof the same way. Leave the tops or plumb cuts of those end rafters resting against each other. Slide a ridge board, typically one size larger than the rafters, such as a 2-by-6-inch for 2-by-4 rafters, inside the opposing rafters from the bottom. Level that board and nail the rafters to it from each side.

Install other rafters the length of the roof, working in pairs. Nail each rafter end to the wall cap with three framing nails and to the ridge board.

Install metal "hurricane" ties on each rafter once all pairs are nailed to the cap and the ridge. Place ties with one side flat against the inside of the cap board and the other side up the side of the rafter. Fasten ties with 8d galvanized nails driven into the boards.