How Many Square Feet Is An Average Attic

Multiply the length of the attic times the width in feet to find the attic area then divide by 150 to find the total square feet of vent space needed.

How many square feet is an average attic.

The roof pitch or roof slope is usually shown as a ratio to 12 i e 1 12 4 12 12 12 etc. Attic vent fans are commonly. For example if the height of your attic is 8 feet then 8 2 4. For example if the base is 12 feet and the height is 10 feet the square footage is 6 x 10 60 feet.

Step 5 add together the square footage values of the square rectangular and triangular floor areas to find the total square footage of your attic. 2200 square foot home x 8 inch ceiling height 17600 cubic feet. Calculate the total vent area needed. Measure the height of your attic in feet.

Because vents are rated in square inches you need to convert the square feet required to square inches. As an example let s use a home that measures 2200 square feet has an average floor to ceiling height measurement of 8 feet and a whole house fan with cfm rating of 1600. The federal housing administration recommends 1 square foot of attic ventilation for every 150 square feet of attic space. Next multiply the square feet of attic space by 0 7 to get the minimum number of cubic feet of air per minute that the fan should be rated to move.

To get the area of the attic floor. Make sure to measure in the center at the attic s highest point. Length x width of attic in feet 150 total sq. Divide the attic s square footage by 150.

Of total vent space needed. Add an additional 20 cfm x 1 20 if you have a steep roof and 15 cfm x 1 15 for a dark roof. Divide this number by two. Ft divided by 150 equals 10 sq.

Attic x 0 7 700 cfm minimum fan rating. With full home additions costing 75 000 minimum and usually far higher many homeowners search for creative ways to increase living space without overly decreasing their bank account. For example if your length is 40 feet and your width is 20 feet then 40 20 800 square feet. Thus 6 66 divided by 2 3 33 square feet of attic ventilation for intake and 3 33 square feet of attic ventilation for exhaust.

Determine the home s cubic measurement by multiplying the square footage by ceiling height. A 50 x 30 attic would have a total area of 1 500 sq.