Square Footage Of Vent For Roof

Nfa is the unobstructed area through which air can pass through a vent usually measured in square inches.

Square footage of vent for roof.

Divide the attic s square footage by 150. Nine hundred square inches equals 6 25 square feet. Calculate the square footage of your attic. Foam roofing costs 4 50 per square foot installed and an additional 1 63 sf to remove the original roof bringing it to 6 85 per square foot to account for roof pitch.

If there is no vapor barrier double it to one square foot of nfa for every 150 square feet of attic floor space half for intake half for exhaust. Roof vents choose one of the following products to meet the recommended exhaust nfva of 528 square inches. Measure the length and width of the attic space using a tape measure. The calculator cannot account for complex shapes based on a measurement of square footage alone.

How to determine the number of attic vents 1. Cut that number in. Intake exhaust airflow in a house attic square footage 2 square inches of exhaust and square inches of intake net free area nfa needed. Here it is a handy shortcut for quick calculations.

In cases where a roof has a complex shape such as in the image to the right measuring the dimensions and areas of each part of the roof to calculate total area will result in a more accurate measurement of area. 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. If there is no vapor barrier you will need one square foot of nfa for every 150 square feet of attic. So the ridge ventilation has exceeded the minimum requirement.

See quantities below for each gaf ventilation product typically rounded up. The costs for foam roofing on a 1 100 1 500 2 400 and 3 000 square foot home are 7 535 10 275 16 440 and 20 550. Ventsure 4 foot strip heat moisture ridge vent 27 lineal feet required. Hit the calculate button for the recommended amount of exhaust and intake 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. Enter the length and width of the attic floor or the total square footage of the attic floor. 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. For attics with a vapor barrier figure one square foot of nfa for every 300 square feet of attic floor area.

Our roof is 50 feet long so using a standard product we will get 900 square inches of ventilating space.