How Far Apart Should Roof Vents Be Placed

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.

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. 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. Putting them at mid roof or lower is ineffective. Fan calculation as a general rule your roof needs 1 square foot of vent area for every 150 square feet of attic space.

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. This video has examples of both static and ridg. Space the vents at the bottom and top of the attic equally according to house size. This is ok provided the vents are near the ridge.

Thus if your attic is 450 square feet you need roof vents equaling 3 square feet. Usually such vents are placed on just one slope of the roof so that they are not visible from the front of the building. Proper installation number and location of roof ventilation is needed to maximize the performance of a roof. In this case they should be placed near the ridge so that the upper attic will be vented.

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.