How Many Roof Vents Do I Need

You will need to have 1 square foot of vent area for every 150 square feet of attic space.

How many roof vents do i need.

The net free area nfa ratingindicates the amount of space each roof vent covers. And this guideline you ll need a minimum of. 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.

Near ridge of the roof. How many vents will my house need. Some local building codes carry special considerations that take precedence. 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.

Always have a balanced ventilation system. Thus if your attic is 450 square feet you need roof vents equaling 3 square feet. Choosing round soffit vents for. 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.

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. Keep in mind you should always consult with a professional roofing company when determining how many air vents your roof should have. For example if you have 1200 square feet of attic space you should need at least 4 air vents to ensure proper ventilation. 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.

You ll need the square footage of your attic to calculate the number of roof vents that you should need.