Calculating Attic Size

How to size attic exhaust vent fans for your home attic size.

Calculating attic size. Next multiply the square feet of attic space by 0 7 to get the minimum number of cubic feet of air per. Divide this number by two. Let owens corning roofing help you calculate exactly how much ventilation you will need for a healthy and balanced attic with our 4 step ventilation calculator. The formula above gives an approximate value of the cfm needed for an attic fan.

To determine the size of your attic multiply the width by the length of the attic floor in feet. I ll do this on the right side of the house which is a 12 12 pitch. Calculate or enter the square footage of the attic or area to be vented. Make sure to measure in the center at the attic s highest point.

If this distance measures 4 inches you have a 4 in 12 pitch. Measure the length and width of the attic floor space to be ventilated. Click the button to calculate the depth in inches and pounds of total insulation required for this job. The word denotes the framing or composition which helps that covering also.

It s the covering on the uppermost part of the building or shelter which gives protection from pets or animals and weather notably rain or snow but heat also sunlight and wind. Pitch measurement method 2. Measure the length of your attic in feet. Cfm cubic feet per minute is a measure of the amount of air the fan moves in a minute.

Measure the width of your attic in feet. This attic ventilation calculator computes the size and number of solar powered attic fans to achieve the proper ventilation for your attic. Attic truss room size calculator a rooftop is part of a building envelope. On a ladder beside the roof place the level a foot or so up the roof hold it level and measure from the 12 inch mark on the level s bottom straight down to the roof.

Next we need to calculate the 5 and 8 ceiling lines. So draw up a simple cross section showing the outside wall a rafter set at the correct pitch and a floor system. Click to see full size image. 8 inches and you have an 8 in 12 pitch.

Input length width and desired r value of the area to be insulated. We also need to allow for the floor system in our calculations. Measure the height of your attic in feet.