Building Code defines the attic as length x width, floor of the attic. That produces a "square footage" number.
You determine this by multiplying the LENGTH x WIDTH of the space. For example, if you attic floor area is 30′ x 50′ then you're measuring 1,500 sq ft. Check out our *NEW* SuperPerf™ AtticFoil™ that was designed for laying on the attic floor in cold climates.
Attic volume is calculated the same way – LxWxH. When the roof pitch is the same on both sides of the roof you can multiply the length of the roof section times half the total (building) width times the height of the roof. This works because the two halves make a rectangular whole.
In general, staircases and closets count as finished square footage, while spaces like garages, three-season porches and unfinished basements or attics are not included. When in doubt on the square footage of a home, refer to MLS information, your purchase agreement or your own measurements.
Grab your tape measure, and measure the length and width of each room, hall, stairwell, closet, etc. whose ceilings touch the attic floor. Multiply the length x width, and you will arrive at ft2, (square feet). Total all your answers, and you will arrive at a good estimate of your attic size.
This rule means, at least half of your attic space must be 7 feet high by 7 feet wide, with a total of 70 square feet. Keep in mind, codes vary from place to place, but for using the attic as an actual room, this rule typically applies.
Areas such as home additions may have different levels of insulation. Prior to measuring, group these areas separately if necessary. Multiply the length and width of each rectangle to get the area. (Area A+ Area B+ Area C) ÷ 144 = total square feet.
To find the square footage, simply multiply the length and width. For example, if you want to find the square footage 20 feet × 20 feet floor, then multiply the dimension 20 x 20. Hence, the square footage of 20 feet × 20 feet floor is 400 square feet.
Multiply the width of your building by the roof pitch to estimate the attic area. Adjust this calculation based on your roof's pitch: for pitches under 5:12, multiply by 1.2 to 1.3; for 6:12 to 8:12, use 1.3 to 1.4; for 10:12 and higher, use 1.4 to 1.5.
Today, built-ins remain popular for several reasons. First and foremost, they're great space-savers, freeing up a lot of floor area. They're an excellent, efficient way to store items in cottages and apartments, which often lack basements and attics.
The IRC requires 1 square foot of net free ventilation area to every 150 square foot of attic floor space (1/150), but does not specify the location of intake vents or exhaust vents, nor does it specify the ratio of intake to exhaust.
A general guideline is homeowners need one square foot of roof vent for every 300 square feet of ceiling space, if your home has a roof with a vapor barrier, or 1:300. If not, you should have one square foot of roof vent for every 150 square feet, or 1:150.
Standard openings are 22.5” x 54”, but some homes have wider openings. Conversely, some homes have smaller openings (or hatches). It's important to understand the opening size you have or will create to ensure you select the correct attic ladder product for your home.
Technically, an attic is any space in a house that is between the roof and the top floor. Make note of any hatches or tiny doorways you see around your house because they may lead to exactly that: an attic!
Multiply your house length by your house width to get the area. (For example, 40 feet x 30 feet = 1,200 square feet.) Next, multiply the area by your roof's pitch. (1,200 x 1.05 = 1,260 square feet.)
Ideally, the attic floor square footage would be measured at the attic floor length x width (regardless of roof pitch, by the way).
Measure the length and width of the building's walls. Multiply the length and width measurements to find square footage. Remember to multiply the square footage times the number of floors in the building if your facility has more than one floor.
12 inches by 12 inches is equal to 144 square inches. To convert square inches to square feet, divide the number of square inches by 144 (since there are 144 square inches in one square foot). So, 144 square inches divided by 144 is equal to 1 square foot. Therefore, 12 inches by 12 inches is equal to 1 square foot.
To do so, take the square footage of the space and divide it by either the depth or the desired R-value. Our blow-in insulation calculator can help take the guesswork out of scoping and pricing for your next cellulose insulation project.
Measure the length and width, in feet, of each room. Then, multiply the length by the width to calculate that room's square footage. For example: If a bedroom is 12 feet by 20 feet, it is 240 square feet (12 x 20 = 240). For each room, write the total square footage in the corresponding space on your sketch.