How To Figure Required Air Vent For A Roof

Jones takes this measurement and divides it by 150 for a total of 7 36 square feet of ventilation space that is needed.

How to figure required air vent for a roof.

How to determine the number of attic vents. If you have 3 000 square feet of attic space this equates to 20 square feet of ventilation needed. Based on your 1100 sq. You can calculate attic ventilation requirements by determining the square footage of your attic floor its width times its length and compare that to the total required net free area nfa.

Divide the square footage by 150 to calculate the area of ventilation needed since you need 1 square foot of vent space for each 150 square feet of attic space. In our case the required 4 vents for the 1200 sq ft house multiply the 144 cubic inches by 4 576 cubic inches. 1 cubic foot is 12 x 12 144 cubic inches. Next multiply the 4 square feet into cubic inches.

The federal housing administration recommends 1 square foot of attic. 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 find the right calculator divide the attic floor space by 300 sq feet. Divide the attic s square footage by 150.

Near ridge of the roof. Jones must now take this required ventilation space and compare it against the total ventilation that he currently has for his attic space. And this guideline you ll need a minimum of. Attic ventilation soffit intake to ridge outlet air flow or square inches ratio.

Measure the length and width of the attic space using a tape measure. Multiple these two. 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. Adding under roof ventilation is usually a great idea but if the relative sizes of the intake and outlet vents are not proper the building will suffer increased heat loss and thus an unnecessarily high home heating bill.

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. Calculate the square footage of your attic. 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. This ratio is required for modern insulated homes.

If your roof is 1200 sq ft soffit floor space you will need 4 sq feet of roof ventilation. 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.