Minimum Attic Ventilation Requirements

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Minimum attic ventilation requirements.

For the 1 150 attic ventilation requirement simply double the amount of exhaust and intake calculated. The roofing industry also has practical guide lines for attic ventilation. In order to have a balanced ventilation system you need to have the right roof vent calculation. Of net free area of exhaust needed at or near the ridge.

Current regulations state that the minimum attic ventilation requirements are 150 1. Code requirements the international building code. Based on your 1100 sq. 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. Exhaust nfva near ridge of the roof. Intake vents located at the lowest part of the roof under the eaves. Figure 1 soffit to ridge attic ventilation.

As an example in an attic that is 30 feet by 20 feet you would have 600 square feet of floor area. The federal housing authority fha and the urban development hud have established minimum requirements for attic ventilation. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. The ventilation amount and opening size requirements can be found in section 806 roof ventilation of chapter 8 roof ceiling construction.

Proper attic ventilation can be an impor tant performance consideration when design ing and installing steep slope roof systems. Typically building codes include minimum requirements applicable to attic ventilation. Ridge static attic vents 384 00 minimum sq. Of net free area of intake needed at or near the soffit.

This means that if you have a 1500 sq attic then you would need at least 10 sf of 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. The majority of the requirements related to attic ventilation have not changed much from the previous editions. 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.

The following are the requirements taken directly from the irc.