How Many Roof Vents Per Square Foot

1 square foot of ventilation for every 300 square feet of space for pitched roofs with vapor barriers 1 square foot of ventilation for every 150 square feet of space no vapor barrier and for some municipalities in hot climates.

How many roof vents per square foot.

To find the squares divide the overall roof area by 100 and then round up. This means that for every 300 square feet of enclosed attic space 1 square foot of ventilation is required with half at the upper portion exhaust vents and half in the lower portion intake vents. What are the building code requirements for ventilating a roof. According to their requirements you should have 1 square foot of attic ventilation per 300 sq ft of attic floor space.

A square simply refers to a 10 x 10 square of roofing. 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. This is simply 100 square feet of roof. There should also be a 50 50 balance of attic venting and roof venting.

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. Enter square footage calculate or enter the square footage of the attic or area to be vented. This formula is traditionally used for static roof vents which are rated for net free area in terms of square inches. Thus if your attic is 450 square feet you need roof vents equaling 3 square feet.

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. 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. 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. 6 measure the radius of round vents or take half the diameter of the.

If your roof is 1200 sq ft soffit floor space you will need 4 sq feet of roof ventilation. 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. As a general rule your roof needs 1 square foot of vent area for every 150 square feet of attic space.