Attic Vent Chute Requirements

The majority of the requirements related to attic ventilation have not changed much from the previous editions.

Attic vent chute requirements.

The ventilation amount and opening size requirements can be found in section 806 roof ventilation of chapter 8 roof ceiling construction. For improved air circulation in the attic install the durovent 22 in. Allows cool dry air to enter the attic. Without exception you should talk to a professional to determine what your home requires.

It is compatible with 3 or 4 ductwork and includes a 3 to 4 adapter for convenience. Use it between rafters to create an air channel through insulation to help keep air flowing freely in your attic. 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. Most typical attic vent chute sizes are 16 and 24 to match open space between the roof framing members.

Generally speaking you need a ratio of 1 300 where for every 300 square feet of ceiling space you need 1 square foot of attic ventilation. Typically made from polyvinyl chloride rigid foam board or cardboard they can be installed with a few. This cap features both a back draft damper and bird screen preventing outside air from entering the home and birds and small pests from entering duct work. Ventsure inflow intake vent.

That said air resistance and interference such as vent grates reduces the area of true ventilation. Choose one of the following products to meet the recommended intake nfva of 528 square inches. 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. The following product options will allow you to achieve an intake nfva of 528 square inches.

Baffles are also called wind baffles venting chutes rafter vents or insulation baffles. The net free vent area nfva shall not be less than 1 150 of the area of the space being vented. If you live in a cold climate checking the attic during the winter will help you make a better determination. Attic inspection required the only way to determine whether you need attic vent chutes is to make a journey into the attic.

The following are the requirements taken directly from the irc. It can be cut to fit most joist spaces and is an affordable way to meet energy code requirements for air flow. This is where you will be able to see what is actually going on there as far as airflow and condensation.