Attic Ventilation Requirements

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.

Attic ventilation requirements.

Divide the square footage item 1 by 300. Hence you would need two square feet 600 300 of attic ventilation. Typically building codes include minimum requirements applicable to attic ventilation. Current regulations state that the minimum attic ventilation requirements are 150 1.

Prior to installing the ridge vent a 1 inch wide strip of roof decking is cut out along both sides of the ridgeline to allow for air movement through the vent. Code requirements the international building code. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. Foot of ventilation for every 150 sq.

Attic ventilation is an important part of keeping your building healthy. The ventilation amount and opening size requirements can be found in section 806 roof ventilation of chapter 8 roof ceiling construction. Calculating attic ventilation requirements. The recommended ventilation ratio to provide for vented attic assemblies when an air barrier is present is the 1 300 ratio as specified by most building codes.

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. Roof insulation thermal resistance at roof perimeter should be equal or greater to thermal resistance of exterior wall. Proper attic ventilation can be an impor tant performance consideration when design ing and installing steep slope roof systems.

Attic ventilation requirements how many attic vents your roof needs industry standard for proper attic ventilation recommends for no vapor retarder type of attic insulation no paper plastic or aluminum layer between the attic floor and insulation layer 1 sq. The roofing industry also has practical guide lines for attic ventilation. Intake vents located at the lowest part of the roof under the eaves allow cool. The two square feet is divided equally between the intake and the exhaust one square foot for each.

A ridge vent is a ventilation strip that is placed along the ridgeline of the home. 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. Feet of attic space divided 50 50. This means that if you have a 1500 sq attic then you would need at least 10 sf of ventilation.

Result of item 1 300. It is important that air movement occurs and is not impeded by any framing members of the.