Proper Roof Vent Spacing

For vaulted or cathedral roof construction provide a free ventilation path from eaves to ridge between all rafters.

Proper roof vent spacing. Place all the roof vents on the same side of the roof. These ventilation needs are calculated differently. Measure the length and width of the attic and multiply the two together. Vent area ranges from about 35 sq in.

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. There are some styles of vaulted ceiling homes or flat roof homes that have ventilation spaces within the roof itself and no attic. It is important that air movement occurs and is not impeded by any framing members of the home. Based on your 1100 sq.

Per vent does not provide uniform ventilation between all rafter bays. Near ridge of the roof. The key to proper ventilation of your roof and attic is balance. Mark the roof venting locations from the attic where you can see the rafters and avoid placing roofing vents over them.

This video has examples of both static and ridg. Proper installation number and location of roof ventilation is needed to maximize the performance of a roof. A ridge vent is a ventilation strip that is placed along the ridgeline of the home. For example 1 500 square feet of attic space requires 10 square feet of vent space.

Conventional rigid aluminum ridge vent typical 20 sq in. Roof louvers or spot vents typical 50 sq in. If your roof peak runs parallel to the street put them on the backside where they ll be less prominent. Prior to installing the ridge vent a 1 inch wide strip of roof decking is cut out along both sides of the ridgeline to allow for air movement through the vent.

And this guideline you ll need a minimum of. Per linear foot covered by cap shingles est. The final number will be the total vent space needed for your attic.