Minimum Attic Ventilation Requirements

Proper attic ventilation can be an impor tant performance consideration when design ing and installing steep slope roof systems.

Minimum attic ventilation requirements.

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. Typically building codes include minimum requirements applicable to attic ventilation. In order to have a balanced ventilation system you need to have the right roof vent calculation. Attic ventilation is an important part of keeping your building healthy.

For the 1 150 attic ventilation requirement simply double the amount of exhaust and intake calculated. The majority of the requirements related to attic ventilation have not changed much from the previous editions. 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 ventilation amount and opening size requirements can be found in section 806 roof ventilation of chapter 8 roof ceiling construction.

The following are the requirements taken directly from the irc. Intake vents located at the lowest part of the roof under the eaves. 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. Current regulations state that the minimum attic ventilation requirements are 150 1.

Exhaust nfva near ridge of the roof. According to their requirements you should have 1 square foot of attic ventilation per 300 sq ft of attic floor space. Ridge static attic vents 384 00 minimum sq. The federal housing authority fha and the urban development hud have established minimum requirements for attic ventilation.

Based on your 1100 sq. This means that if you have a 1500 sq attic then you would need at least 10 sf of ventilation. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. Code requirements the international building code.

And this guideline you ll need a minimum of. Of net free area of exhaust needed at or near the ridge. The roofing industry also has practical guide lines for attic ventilation. 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.

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.