How to Install a Vent on a New Asphalt Roof

Climb into your house’s attic through the access in the ceiling. Determine where you want to install the vent in relation to the device you need to ventilate, and drive a screw that is two inches or longer through the roof from inside the attic, between the wood joists. If you do not have an attic, determine where in the house's ceiling you need to install the vent and drive the screw through the ceiling and the roof.

Climb onto the house’s roof using a ladder and locate the screw coming out of the roof. Place the duct portion of the roof vent assembly against the shingles, with the screw centered inside the duct, and trace around the duct with a piece of chalk.

Remove the roof vent and cut through the shingles and underlayment along the chalk outline, using the utility knife. Drill a hole into the roof’s wood you have exposed, allowing you to insert a jigsaw’s blade into the wood. Cut through the roof, following the same line you used to cut through the shingles.

Insert only the roof vent’s duct piece into the opening in the roof, leaving about half of the duct coming out of the roof. Drive sheet metal screws through the inside of the duct and into the roof, anchoring the duct in place.

Insert the vent hood over the duct in the roof. Cut through any shingles that press against the hood, and pry up any nails that keep the hood’s flange from sliding under the shingles above the vent opening.

Apply roofing cement to any portions of the hood’s flange that sits under shingles, and then press the shingles over the flange. Drive roofing nails through the edges of the exposed portion of the roof vent.