How To Figure Required Air Vent For A Roof

This ratio is required for modern insulated homes.

How to figure required air vent for a roof.

Divide the attic s square footage by 150. Multiple these two. Next multiply the 4 square feet into cubic inches. Measure the length and width of the attic space using a tape measure.

How to determine the number of attic vents. Jones must now take this required ventilation space and compare it against the total ventilation that he currently has for his attic space. The federal housing administration recommends 1 square foot of attic. 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. Attic ventilation soffit intake to ridge outlet air flow or square inches ratio. 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. In order to find the right calculator divide the attic floor space by 300 sq feet.

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 for every 300 square feet of attic floor space evenly split between intake and exhaust. If you have 3 000 square feet of attic space this equates to 20 square feet of ventilation needed. This calculator gives you the required attic ventilation requirement.

And this guideline you ll need a minimum of. 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. 1 cubic foot is 12 x 12 144 cubic inches. Near ridge of the roof.

How many vents will my house need. Jones takes this measurement and divides it by 150 for a total of 7 36 square feet of ventilation space that is needed. Calculate the square footage of your attic. In our case the required 4 vents for the 1200 sq ft house multiply the 144 cubic inches by 4 576 cubic inches.

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.