Attic Space Venting Requirements

The following is a list of options for installing ventilation into a residential attic space.

Attic space venting requirements.

Prior to installing the ridge vent a 1 inch wide strip of roof decking is cut out along both sides of the ridgeline to allow for air movement through the. Allows cool dry air to enter the attic. The two square feet is divided equally between the intake and the exhaust one square foot for each. A ridge vent is a ventilation strip that is placed along the ridgeline of the home.

Choose one of the following products to meet the recommended intake nfva of 528 square inches. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. Calculating attic ventilation requirements. Hence you would need two square feet 600 300 of attic ventilation.

Attics must have a minimum of 1 square foot of ventilation openings for every 150 square feet of floor space. In order to find the right calculator divide the attic floor. It really is a design choice. Requirements for unvented attics can be found in section r806 5 of the 2018 irc.

Calculate net free vent space. Code requirements the international building code. According to their requirements you should have 1 square foot of attic ventilation per 300 sq ft of attic floor space. If your roof is 1200 sq ft soffit floor space you will need 4 sq feet of roof ventilation.

Divide the square footage item 1 by 300. Intake vents located at the lowest part of the roof under the eaves allow cool. So the decision to vent an attic space is not dictated by building code. If the attic is equipped with high and low ventilation openings the requirement is 1.

The roofing industry also has practical guide lines for attic ventilation. Result of item 1 300. Proper attic ventilation consists of a balance between air intake at your eaves soffits or fascias and air exhaust at or near your roof ridge. Calculate the square footage of the attic space.

There should also be a 50 50 balance of attic venting and roof venting. Typically building codes include minimum requirements applicable to attic ventilation. This section contains an extensive list of requirements and conditions that have to be met in order to have an unvented attic. The venting space should be equally divided between intake.

The following product options will allow you to achieve an intake nfva of 528 square inches.