How Many Roof Vents Do I Need

Near ridge of the roof.

How many roof vents do i need.

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. You will need to have 1 square foot of vent area for every 150 square feet of attic space. Thus if your attic is 450 square feet you need roof vents equaling 3 square feet. 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. You ll need the square footage of your attic to calculate the number of roof vents that you should need. For example if you have 1200 square feet of attic space you should need at least 4 air vents to ensure proper ventilation. 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.

The net free area nfa ratingindicates the amount of space each roof vent covers. Based on your 1100 sq. Fan calculation as a general rule your roof needs 1 square foot of vent area for every 150 square feet of attic space. Always have a balanced ventilation system.

Keep in mind you should always consult with a professional roofing company when determining how many air vents your roof should have. Choosing round soffit vents for. In no case should the amount of exhaust ventilation exceed the amount of intake ventilation. 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.

And this guideline you ll need a minimum of.