Attic Vents Per Square Foot

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.

Attic vents per square foot.

Based on your 1100 sq. 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. Building codes typically echo the administration s guidelines. So if your attic is 1 500 sq.

Our roof is 50 feet long so using a standard product we will get 900 square inches of ventilating space. Milt the rule of thumb on the amount of vent space needed is approximately 1 sq. So the ridge ventilation has exceeded the minimum requirement. Ft you divide that by 150 to get 10 sq.

Near ridge of the roof. And this guideline you ll need a minimum of. Nine hundred square inches equals 6 25 square feet. This helps make it easy to calculate how many vents you need for your attic once you ve determined your requirements.

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. The federal housing administration recommends 1 square foot of attic ventilation for every 150 square feet of attic 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. 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.

Of vent space for every 150 sq. 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. Attic vent fans are commonly rated from 800 to 1 600 cfm making one fans suitable for attics of up to around 2 200 square feet. If your attic floor has a vapor barrier you will need one square foot of nfa per every 300 square feet of attic floor area half of that will be intake half for exhaust.