How to Add a Roof Over an Exterior Door

Cut two 2-by-4 boards 60 inches long with a reciprocating saw. This covers the door width plus adds 12 inches of overhang on each side. Cut four 2-by-4s 40 inches long and six more boards 24 inches long.

Lay out one 60-inch board and two 40-inch boards. Overlap the ends and form a triangle. Draw the angles on the ends of the boards that are needed so the ends of the boards will fit together. The angles connecting to the long board will be about 19 1/2 degrees each and the peak angles will be 51 degrees each.

Trim the angles on the first three boards with a miter saw and then check to see that they fit together properly. Transfer the angles to three more matching boards and cut. Connect the boards into two triangles using galvanized steel connector plates, known as gusset plates, and 1 1/2-inch screws on the front of the triangles. Place more connector plates on the backside of the triangles to give the trusses added strength. Trace one of the triangles onto a sheet of plywood for the end cap.

Match the corners up on the triangles. Screw one of the ends of a 24-inch board to one side of the peak of the triangle. Line up the edges while securing the board. Screw the other end to the other triangle in the corresponding position. Attach another 24-inch board to the other side of the peak. The two boards form the peak across the top of the roof frame. Screw the other 24-inch boards on each side of the remaining corners.

Lift the frame and secure it 12 inches above the exterior door. Use a carpenter’s level to keep the frame straight and center the structure over the center of the door. Hanging the roof frame to the house takes at least three people. Two people need to hold the structure in place while the third person secures the roof frame to the house.

Screw the frame in place with 4-inch screws placed every 3 inches through the 2-by-4s with an electric screwdriver. Push two 2-by-4s the length from the lower end of the roof to the ground under the front of the structure to hold the frame in place while adding the permanent supports.

Place a concrete pier block with support bracket directly under each corner of the frame. Measure the distance between the lower edge of the frame and the support bracket with a tape measure. Cut two 4-by-4 boards the same length as the measurement. Drill a hole in the bottom end of the boards for the bolt. Place the end in the support bracket and secure with a bolt and nut. Screw the frame corners into the top of the 4-by-4s. Remove the temporary 2-by-4 supports.

Measure the roof areas and draw the rectangle pieces on the plywood. Cut the end cap and the two roof pieces out. Screw the end cap to the front of the frame and the roof pieces to the top. Cover the roof area with tar paper and nail on the shingles. Finish the roof with a roof cap, which seals the roof to prevent leaks. Paint the exposed wooden pieces of the porch roof with exterior paint and a paintbrush.