How Far Apart Should Roof Vents Be Placed

If your attic floor has a vapor barrier you will need one square foot of nfa per every 300 square feet of attic floor area half of that will be intake half for exhaust.

How far apart should roof vents be placed.

Thus if your attic is 450 square feet you need roof vents equaling 3 square feet. Ideally half the vents should be located in the soffit at the bottom of the roof and half in gable or ridge vents near the top to allow for natural circulation of air through the attic. Usually such vents are placed on just one slope of the roof so that they are not visible from the front of the building. For the previous example you would need 20 soffit vents.

Proper installation number and location of roof ventilation is needed to maximize the performance of a roof. Fan calculation as a general rule your roof needs 1 square foot of vent area for every 150 square feet of attic space. In this case they should be placed near the ridge so that the upper attic will be vented. You need to have an equal number of vents located at the bottom of the attic or under the roof easement as you have at the top of the attic near a gable or ridge.

The general rule of thumb on the amount of total attic vent space needed is to have at least one square foot of vent space for every 150 square feet of attic area. They should be divided equally between inlet and outlet vents and they can be used in any combination that will work with your roof s design. This video has examples of both static and ridg. If there is no vapor barrier double it to one square foot of nfa for every 150 square feet of attic floor space half for intake half for exhaust.

Space the vents at the bottom and top of the attic equally according to house size.