For example 1 500 square feet of attic space requires 10 square feet of vent space.
Proper roof vent spacing.
There are some styles of vaulted ceiling homes or flat roof homes that have ventilation spaces within the roof itself and no attic.
Per linear foot covered by cap shingles est.
Place all the roof vents on the same side of the roof.
For vaulted or cathedral roof construction provide a free ventilation path from eaves to ridge between all rafters.
Measure the length and width of the attic and multiply the two together.
It is important that air movement occurs and is not impeded by any framing members of the home.
Take the solution and divide it by 150.
A ridge vent is a ventilation strip that is placed along the ridgeline of the home.
The final number will be the total vent space needed for your attic.
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.
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.
This video has examples of both static and ridg.
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.
These ventilation needs are calculated differently.
Near ridge of the roof.
Conventional rigid aluminum ridge vent typical 20 sq in.
The key to proper ventilation of your roof and attic is balance.
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.
If your roof peak runs parallel to the street put them on the backside where they ll be less prominent.
Vent area ranges from about 35 sq in.
And this guideline you ll need a minimum of.
Based on your 1100 sq.
Roof louvers or spot vents typical 50 sq in.
