Attic Ventilation Required

Code requirements the international building code.

Attic ventilation required.

Feet of attic space divided 50 50. Proper attic ventilation can be an impor tant performance consideration when design ing and installing steep slope roof systems. The following are the requirements taken directly from the irc. You can also contact your local municipality to check on building code in your area.

Intake vents located at the lowest part of the roof under the eaves allow cool. Most building codes require a ratio of 1 150 ventilation space to attic floor space. The majority of the requirements related to attic ventilation have not changed much from the previous editions. However the utility of attic ventilation fans is actually quite a controversial topic.

Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. About attic ventilation natural attic ventilation. Allows cool dry air to enter the attic. Foot of ventilation for every 150 sq.

Good insulation reduces fan effectiveness. 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. Good ventilation allows the heat and moisture to escape. 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 ventilation amount and opening size requirements can be found in section 806 roof ventilation of chapter 8 roof ceiling construction. Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca. The following product options will allow you to achieve an intake nfva of 528 square inches. In the winter warm moist air seeps into the attic from the living space below.

How to determine whether you need better attic ventilation. The roofing industry also has practical guide lines for attic ventilation. In the summer good attic ventilation reduces heat buildup. 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 downside of attic ventilation fans. At first it may seem odd to add insulation for warmth and then purposely allow cold air to enter the attic through vents but this combination is the key to a durable and energy efficient home. Typically building codes include minimum requirements applicable to attic ventilation.