How Much Roof Vents Do I Need

Rounding up you would need ten 10 750 vents.

How much roof vents do i 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. Proper attic ventilation consists of a balance between air intake at your eaves soffits or fascias and air exhaust at or near your roof ridge. If the slope of your roof is greater than 6 12 you will need more ventilation to reflect the extra volume of attic space. In other words the entire vent opening doesn t count as vented space.

As a general rule your roof needs 1 square foot of vent area for every 150 square feet of attic space. And this guideline you ll need a minimum of. How many vents will my house need. Thus if your attic is 450 square feet you need roof vents equaling 3 square feet.

Building codes vary. Near ridge of the roof. To calculate the number of 750 vents needed divide 480 by 50 to get 9 6 vents. 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.

In order to facilitate this exchange of warm and cool air the general rule of thumb suggests installing at least 1 sq. 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. Of vent for every 300 sq. Proper attic ventilation consists of a balance between air intake at your eaves soffits or fascias and air exhaust at or near your roof ridge.

Asphalt roofing and nrca. 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. This shortcut conveniently calculates the 2015 international residential building code minimum irc section r806 roof ventilation 1 which states in part 1 square foot of net free area for every 150 square feet of attic floor space with the attic defined as length x width floor of the attic. That said air resistance and interference such as vent grates reduces the area of true ventilation.

Based on your 1100 sq.