Minimum Attic Ventilation Requirements

Code requirements the international building code.

Minimum attic ventilation requirements.

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. Intake vents located at the lowest part of the roof under the eaves. According to their requirements you should have 1 square foot of attic ventilation per 300 sq ft of attic floor space. Attic ventilation is an important part of keeping your building healthy.

Current regulations state that the minimum attic ventilation requirements are 150 1. Of net free area of exhaust needed at or near the ridge. And this guideline you ll need a minimum of. Based on your 1100 sq.

The following are the requirements taken directly from the irc. Ridge static attic vents 384 00 minimum sq. The roofing industry also has practical guide lines for attic ventilation. The ventilation amount and opening size requirements can be found in section 806 roof ventilation of chapter 8 roof ceiling construction.

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. 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. Exhaust nfva near ridge of the roof. Typically building codes include minimum requirements applicable to attic ventilation.

This means that if you have a 1500 sq attic then you would need at least 10 sf of ventilation. For the 1 150 attic ventilation requirement simply double the amount of exhaust and intake calculated. Proper attic ventilation can be an impor tant performance consideration when design ing and installing steep slope roof systems. 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.

Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. Of net free area of intake needed at or near the soffit. Figure 1 soffit to ridge attic ventilation. The federal housing authority fha and the urban development hud have established minimum requirements for attic ventilation.

In order to have a balanced ventilation system you need to have the right roof vent calculation.