Attic Space Venting Requirements

Attics must have a minimum of 1 square foot of ventilation openings for every 150 square feet of floor space.

Attic space venting requirements.

So the decision to vent an attic space is not dictated by building code. The following is a list of options for installing ventilation into a residential attic space. Calculating attic ventilation requirements. Calculate the square footage of the attic space.

Hence you would need two square feet 600 300 of attic ventilation. Federal housing authority recommends a minimum of at least 1 square foot of attic ventilation evenly split between intake and exhaust for every 300 square feet of attic floor space. The two square feet is divided equally between the intake and the exhaust one square foot for each. This section contains an extensive list of requirements and conditions that have to be met in order to have an unvented attic.

According to their requirements you should have 1 square foot of attic ventilation per 300 sq ft of attic floor space. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. If your roof is 1200 sq ft soffit floor space you will need 4 sq feet of roof ventilation. Calculate net free vent space.

A ridge vent is a ventilation strip that is placed along the ridgeline of the home. The roofing industry also has practical guide lines for attic ventilation. If the attic is equipped with high and low ventilation openings the requirement is 1. Allows cool dry air to enter the attic.

Code requirements the international building code. Divide the square footage item 1 by 300. The venting space should be equally divided between intake. Proper attic ventilation can be an impor tant performance consideration when design ing and installing steep slope roof systems.

There should also be a 50 50 balance of attic venting and roof venting. Intake vents located at the lowest part of the roof under the eaves allow cool. Typically building codes include minimum requirements applicable to attic ventilation. 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.

In order to find the right calculator divide the attic floor. The following product options will allow you to achieve an intake nfva of 528 square inches. Choose one of the following products to meet the recommended intake nfva of 528 square inches. Result of item 1 300.

Requirements for unvented attics can be found in section r806 5 of the 2018 irc.