How to Install a Cap Shingle

Climb onto the roof and sit with one knee on either side of the roof peak, facing the end of the gable and within arm's reach of it. Fit the first cap shingle, with the flat edge aligned with the edge of the gable. Overlap the bottom edges on each side on top of the installed shingles by about 1 inch in order to shed water.

Nail through the back corners of the shingle with 1 1/2-inch roofing nails with rubber washers. Nail away from the end of the gable. Drive the nails with a 20-ounce hammer for best results. Use two nails in the back half of the shingle on each side of the roof. Overlap the next shingle on the first, about halfway across and covering the nailed half of the first cap shingle. Nail this shingle in place as you did the first.

Continue adding shingles, working toward the center of the roof. Stop an inch or two short of the middle and move to the opposite gable from where you started. Install cap shingles along the ridge, starting from this opposite gable. Overlap and nail each shingle in place, working toward the center to a position opposite and equal to the last shingle on the other side.

Fit one shingle over the ends of the two rows of shingles meeting at the center. Nail through each of the four corners off the shingle to attach it. Drive the nails in firmly until the heads are flush to prevent it lifting up, since this shingle is the "keystone" piece of the ridge, covering the open ends of both rows.