How Many Roof Vents Do I Need In My Roof

For example if you have 1200 square feet of attic space you should need at least 4 air vents to ensure proper ventilation.

How many roof vents do i need in my roof.

Near ridge of the roof. The net free area nfa ratingindicates the amount of space each roof vent covers. You will need to have 1 square foot of vent area for every 150 square feet of attic space. 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.

To calculate the number of 750 vents needed divide 480 by 50 to get 9 6 vents. Use the calculator below to find out how many exhaust and intake vents you will need on your house. Rounding up you would need ten 10 750 vents. As a general rule your roof needs 1 square foot of vent area for every 150 square feet of attic space.

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. 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. Because you always want your intake nfa to meet or exceed the amount of exhaust nfa we will take the amount of exhaust provided and divide by the nfa rating of the deck air. You ll need the square footage of your attic to calculate the number of roof vents that you should need.