How Far Apart Should Roof Vents Be Placed

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.

How far apart should roof vents be placed. Usually such vents are placed on just one slope of the roof so that they are not visible from the front of the building. 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. 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. 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.

In this case they should be placed near the ridge so that the upper attic will be vented. Putting them at mid roof or lower is ineffective. Space the vents at the bottom and top of the attic equally according to house size. 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.

Thus if your attic is 450 square feet you need roof vents equaling 3 square feet. This video has examples of both static and ridg. Fan calculation as a general rule your roof needs 1 square foot of vent area for every 150 square feet of attic space. For the previous example you would need 20 soffit vents.

This is ok provided the vents are near the ridge.