To install a vented ridge cap on a shingle roof, remove the cap shingles and roof decking, install the ridge vents per the manufacturer's instructions, and nail them into place. A vented ridge cap runs the length of a building's roof ridge. The roof ridge is the highest point on a slanted roof, where two sloped sections meet. The ridge vent allows air to circulate between the attic and outside.
- Remove cap shingles
Determine whether the roof has a ridge board by going into the attic and looking for a board that runs the length of the roof, perpendicular to the slanted rafters. If no ridge board is present, snap chalk lines on top of the roof, 3/4- to 1-inch from the peak on each side. If a ridge board is present, snap the chalk lines 7/8- to 1 3/4-inches from the peak on each side. Stop the chalk line 6 inches from the end of the roof. Cut along the chalk lines using a utility knife. Remove the shingles from the ridge to expose the roof decking.
- Remove roof decking
Cut the roof decking along the same lines where the shingles are removed. Pull the decking from around the peak, and dispose of it.
- Install the ridge vent
Insert the end plugs for the first section of the vent per manufacturer instructions. Align the vent flush with the end of the roof and centered over the vent. Nail it into place with 2-inch roofing nails. Nail the remaining sections into place along the length of the ridge. Insert end plugs for the final section. Cut the final section so that it is flush with the end of the roof. Nail it into place.