How Many Roof Vents Do I Need

So if your attic is 450 square feet you will need 3 square feet of vent space evened out throughout the entire space and divided equally between inlet and outlet vents.

How many roof vents do i need.

Choosing round soffit vents for. Federal housing authority recommends a minimum of at least 1 square foot of attic ventilation for every 300 square feet of attic floor space evenly split between intake and exhaust. Fan calculation as a general rule your roof needs 1 square foot of vent area for every 150 square feet of attic space. You will need to have 1 square foot of vent area for every 150 square feet of attic space.

Some local building codes carry special considerations that take precedence. And this guideline you ll need a minimum of. Federal housing authority recommends a minimum of at least 1 square foot of attic ventilation evenly split between intake and exhaust for every 300 square feet of attic floor space. How many vents will my house need.

Near ridge of the roof. Based on your 1100 sq. For example if you have 1200 square feet of attic space you should need at least 4 air vents to ensure proper ventilation. For the number of soffit vents in the example divide 8 square feet of ventilation needed by 0 5 for the number of rectangular vents required 16 in the example.

In no case should the amount of exhaust ventilation exceed the amount of intake ventilation. Thus if your attic is 450 square feet you need roof vents equaling 3 square feet. The rule of thumb used to determine the number of roof vents to install is one for every 300 square feet of attic area if your attic has a vapour barrier and one for every 150 square feet of attic area if the attic does not have a vapour barrier. You ll need the square footage of your attic to calculate the number of roof vents that you should need.

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.