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.
Attic vents per square foot.
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.
The federal housing administration recommends 1 square foot of attic ventilation for every 150 square feet of attic space.
So the ridge ventilation has exceeded the minimum requirement.
And this guideline you ll need a minimum of.
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.
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.
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.
Attic x 0 7 700 cfm minimum fan rating add an additional 20 cfm x 1 20 if you have a steep roof and 15 cfm x 1 15 for a dark roof.
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.
Standard ridge vent produces 18 square inches of ventilating area per lineal foot.
Of vent space for every 150 sq.
So if your attic is 1 500 sq.
Nine hundred square inches equals 6 25 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.
Ben ericksonaugust 30 2007 at 3 09 pm.
Our roof is 50 feet long so using a standard product we will get 900 square inches of ventilating space.
Near ridge of the roof.
Based on your 1100 sq.
Building codes typically echo the administration s guidelines.
