How to install roof vent?

Use a flat bar to carefully pry up the shingles that form the ridge cap on your roof. Try not to damage the shingles as you will be using some of them to re-shingle around the vent you're installing. Late morning is the best time to do this as the shingles will have absorbed the heat of the sun and will be pliable. Leave 8 to 10 inches of shingles in place on either side of a chimney or wall.

Strike a line 7/8 inches from either side of the roof ridge using a chalk line.

Set the blade of your circular saw so that it equals the thickness of the roof sheathing. Cutting too deep means you could run the risk of cutting rafters. Wear eye protection. Cut on either side of the roof ridge following the chalk lines. Leave 8 to 10 inches in front or on either side of a chimney or wall.

Pry up the wood in between the cuts made by the circular saw with a large chisel.

Remove the sheathing with a pry bar. Be certain to remove any exposed nails as well.

Install your roof vent so that it covers or straddles the section of roof you've removed, and nail it into place with roofing nails. Baffled vents are recommended as they prevent air from entering back into the attic, while allowing hot air to escape freely. These vents aren't heavy, but do use caution bringing them up to the roof while your climbing the ladder.

Cover the roof vent with the shingles you removed. Use 1 ½ or 1 ¾ inch corrugated roofing nails. Replace any damaged shingles with ones that closely match the original ones.