Attic Air Ventilation Requirements

There should also be a 50 50 balance of attic venting and roof venting.

Attic air ventilation requirements. According to their requirements you should have 1 square foot of attic ventilation per 300 sq ft of attic floor space. Vents are rated by their net free area or the amount of space for air to flow in or out. Building codes vary. Enter your square footage.

Calculate or enter the square footage of the attic or area to be vented. Does an attic have to be vented. You can also contact your local municipality to check on building code in your area. In the summer natural air flow in a well vented attic moves super heated air out of the attic protecting roof shingles and removing moisture.

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 insulation will resist heat transfer into the house. The federal housing authority fha and the urban development hud have established minimum requirements for attic ventilation. Most building codes require a ratio of 1 150 ventilation space to attic floor space.

To lower attic temperatures and to remove excess moisture. Attic ventilation serves two main functions. Proper insulation and air sealing also keeps attics cold in winter by blocking the entry of heat and moist air from below. Balance is the key.

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. What does the code require. As an example in an attic that is 30 feet by 20 feet you would have 600 square feet of floor area. In order to facilitate this exchange of warm and cool air the general rule of thumb suggests installing at least 1 sq.

Of vent for every 300 sq. I was told there would be no math. Measure the length and width of the attic floor space to be ventilated.