This is accomplished by taking the square feet recommended and multiplying by 144.
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.
Length x width of attic in feet 150 total sq.
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.
Ft divided by 150 equals 10 sq.
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.
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.
The roof pitch or roof slope is usually shown as a ratio to 12 i e 1 12 4 12 12 12 etc.
One way is by working within the home s existing footprint and converting the attic into living space.
A 50 x 30 attic would have a total area of 1 500 sq.
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.
Measure the height of your attic in feet.
Attic vent fans are commonly.
Now that you have the footprint or square footage of the attic space multiply the total roof square footage by the applicable pitch factor to complete your estimate for the amount of foil you will need to cover the roof slopes.
Because vents are rated in square inches you need to convert the square feet required to square inches.
The federal housing administration recommends 1 square foot of attic ventilation for every 150 square feet of attic space.
Of total vent space needed.
Make sure to measure in the center at the attic s highest point.
Determine the home s cubic measurement by multiplying the square footage by ceiling height.
Divide the attic s square footage by 150.
Calculate the total vent area needed.
For example if your length is 40 feet and your width is 20 feet then 40 20 800 square feet.
To get the area of the attic floor.
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.
For example if the height of your attic is 8 feet then 8 2 4.
Attic x 0 7 700 cfm minimum fan rating.