Minimum Attic Ventilation Requirements

Typically building codes include minimum requirements applicable to attic ventilation.

Minimum attic ventilation requirements.

The roofing industry also has practical guide lines for attic ventilation. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. This means that if you have a 1500 sq attic then you would need at least 10 sf of ventilation. Of net free area of intake needed at or near the soffit.

At least code required minimum ventilation b balance ventilation between intake and exhaust c control heat moisture and air fl ow between the attic and the occupied space this document outlines reasons for ventilating roofs provides design guidelines discusses regulatory requirements and identifi es roof ventilation. Ridge static attic vents 384 00 minimum sq. Code requirements the international building code. Figure 1 soffit to ridge attic ventilation.

Of net free area of exhaust needed at or near the ridge. Current regulations state that the minimum attic ventilation requirements are 150 1. According to their requirements you should have 1 square foot of attic ventilation per 300 sq ft of attic floor space. Proper attic ventilation can be an impor tant performance consideration when design ing and installing steep slope roof systems.

Based on your 1100 sq. And this guideline you ll need a minimum of. The following are the requirements taken directly from the irc. The majority of the requirements related to attic ventilation have not changed much from the previous editions.

Intake vents located at the lowest part of the roof under the eaves. Attic ventilation is an important part of keeping your building healthy. As an example in an attic that is 30 feet by 20 feet you would have 600 square feet of floor area. In order to have a balanced ventilation system you need to have the right roof vent calculation.

For the 1 150 attic ventilation requirement simply double the amount of exhaust and intake calculated. The ventilation amount and opening size requirements can be found in section 806 roof ventilation of chapter 8 roof ceiling construction. Exhaust nfva near ridge of the roof. According to the fha federal housing administration us for every 300 square feet of attic floor area you should have at minimum one square foot 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.