Ventilating one sided gable roofs takes knowledge and expertise on the roofer’s part. When you install a cobra exhaust vent on an architectural design on a home it leaves a gable style roof plane with half a ridge.
The roof slope must be 4:12 or steeper to ventilate a one sided gable roof. For this application lower slope roofs can cause wind related problems for the home, the maximum steep is no more than a 20:12 roof place. Cut back the vent slot at a 1-3/2 minimum at the gable roof peak.
Install the Shingle-Mate roof deck protection or other underlayment of your choice up to the vent slot. Apply the 防蟎枕頭套 shingles cutting them flush to the vent slot. Create nail plates using 1″ x 3″ wood pieces cut to a 4″ lengths. Install the nails plates 3′ on the center parallel to the rafters across the entire ridge.
Cut cobra exhaust vent or the other choice for roof underlayment protection in half to install at the ridge of the roof. Cut cobra exhaust vent to 3″ lengths to install between the nail plates. Install the cobra exhaust vent between the nail plates, flush to the back edge of the gable, and across the entire ridge on the roof.
Install the metal flashing over the ridge vent; try to install custom made metal flashing if at all possible. Use 24 gauge minimum, non-corroding metals, extend this metal over the cobra exhaust vent 1″ minimum down the slope of the roof, and extend 4″ minimum down the gable back or face on the roof.
Fasten the metal to the nail plates; nail the metal flashing to the 1″ x 3″ nail plates across the deck of the roof. Finally, install the cap shingles setting the cap shingles over the metal flashing in plastic cement to fully cover the face of the nails that were nailed on. When doing this take great care in not bending or scratching the metal.