A shingled roof requires ventilation. That can be done several ways. Gable vents, turbine vents, air hawks or ridge vent. It is also important that your soffits are vented to get proper airflow.
15 lb felt, 1 1/2'' plastic caps , 20" valley metal, 1 1/4" nails, Ridge vent, 2 1/2" ridge nails, feild shingles, 3 tab shingles (for starters and ridge), air hawks & white drip edge.
To seal the ridge from weather. If a ridge vent is used it is just that, a vent for the roof.
When talking about the area of a roof, remember that it is not the same as the square footage of the structure. For example a 20 x 30' building with a 12" overhang and a 4/12 pitch will have 736 sq ft of roof vs only 600 sq ft of slab. One square of shingles covers 100 square feet. 15 year shingles come 3 bundles to a square. 25 year come 4 bundles to a square. The ridge vent will vary with each job. They are 4' each.
Rake overhangs are not as critical to vent as are the rafter spaces above the living areas, but for the sake of appearance, the entire ridge is usually covered with venting.
ridge vent and powered
WHICH VENT If you're talking plumbing roof vents or soffit or ridge attic air vents; absolutely not!! I can't thing of a single vent that would be opened and closed at will.
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it's easy go with a ridge vent ,remove the caps on the peak of the roof,save them if you can.cut the ridge open with a skill saw , make sure you set the blade on the saw so you do not cut to deep. about 1 in down from the top. do this on both sides of the peek.install the ridge vent and then nail your caps back on.
ocean ridge abyssal plain continental shelf continental slop hydrothermal vent
ocean ridge abyssal plain continental shelf continental slop hydrothermal vent
To seal the ridge from weather. If a ridge vent is used it is just that, a vent for the roof.