Proper Roof Vent Spacing

The final number will be the total vent space needed for your attic.

Proper roof vent spacing.

Conventional rigid aluminum ridge vent typical 20 sq in. Per vent does not provide uniform ventilation between all rafter bays. Based on your 1100 sq. Take the solution and divide it by 150.

There are some styles of vaulted ceiling homes or flat roof homes that have ventilation spaces within the roof itself and no attic. Vent area ranges from about 35 sq in. For example 1 500 square feet of attic space requires 10 square feet of vent space. Place all the roof vents on the same side of the roof.

A ridge vent is a ventilation strip that is placed along the ridgeline of the home. If your roof peak runs parallel to the street put them on the backside where they ll be less prominent. Mark the roof venting locations from the attic where you can see the rafters and avoid placing roofing vents over them. The irc adds that the nfva ratio can also be reduced to 1 300 if 50 to 80 of the required ventilation is located in the upper portion of the attic or cathedral ceiling and the rest is located at the eaves with the upper vents at least 3 feet above the lower.

Per linear foot covered by cap shingles est. These ventilation needs are calculated differently. Near ridge of the roof. The key to proper ventilation of your roof and attic is balance.

Roof louvers or spot vents typical 50 sq in. Install baffles providing a minimum of 1 inch of clear space between framing and or under roof decking at eaves to ensure that ceiling or roof insulation does not block ventilation paths. For vaulted or cathedral roof construction provide a free ventilation path from eaves to ridge between all rafters. And this guideline you ll need a minimum of.

Proper installation number and location of roof ventilation is needed to maximize the performance of a roof. Measure the length and width of the attic and multiply the two together. The amount of space you devote to intake must be equal to the amount you allow for exhaust and these must be calculated according to the size of your attic and slope of your roof.