How to Install Drain-Waste-Vent Pipe Flashing

Loosen the bottom of the shingles that sit above the vent pipe, using a small pry bar to remove any nails from the shingle. Trim the roof shingles that sit just above the vent pipe, using a utility knife, so the shingles do not come within an inch of the vent pipe.

Slide the flashing over the vent pipe and insert it under the shingles to test that the shingles do not contact the raised portion of the flashing. Remove the flashing and trim the shingles back further until they no longer contact the raised portion of the flashing.

Replace the flashing around the vent pipe and slide the flashing under the shingles above the vent pipe. Drive rubber-washered screws through the perimeter of the flashing and the shingles below, except where the flashing is covered by shingles.

Lift up the shingles that sit over the flashing. Apply an even layer of roofing cement to the flashing and then replace the shingles, pressing them against the flashing. Slide the rubber boot, with the wider side down, over the vent pipe until it sits snugly against the flashing.