How To Figure Roof Venting Requirements

1 cubic foot is 12 x 12 144 cubic inches.

How to figure roof venting requirements.

Measure the length and width of the attic floor space to be ventilated. The majority of the requirements related to attic ventilation have not changed much from the previous editions. Our roof is 50 feet long so using a standard product we will get 900 square inches of ventilating space. And this guideline you ll need a minimum of.

Divide the square inches by 2. Of vent space for every 150 sq. Next multiply the 4 square feet into cubic inches. Change the square feet to square inches.

If your roof is 1200 sq ft soffit floor space you will need 4 sq feet of roof ventilation. The ventilation amount and opening size requirements can be found in section 806 roof ventilation of chapter 8 roof ceiling construction. So if your attic is 1 500 sq. Standard ridge vent produces 18 square inches of ventilating area per lineal foot.

Calculating attic ventilation requirements. Ft you divide that by 150 to get 10 sq. Based on your 1100 sq. Enter the length and width of the attic floor or the total square footage of the attic floor.

Nine hundred square inches equals 6 25 square feet. Result of item 3 2. The following are the requirements taken directly from the irc. Calculate the square footage of the attic space.

The rule of thumb on the amount of vent space needed is approximately 1 sq. Result of item 1 300. In order to find the right calculator divide the attic floor space by 300 sq feet. Divide the square footage item 1 by 300.

Result of item 2 x 144. Hit the calculate button for the recommended amount of exhaust and intake ventilation. See quantities below for each gaf ventilation product typically rounded up. Near ridge of the roof.

Most building codes require a ratio of 1 150 ventilation space to attic floor space.