Estimating Ventilation Requirements For Attic

Proper attic ventilation can be an impor tant performance consideration when design ing and installing steep slope roof systems.

Estimating ventilation requirements for attic.

In of vent opening per 150 sq. Typically building codes include minimum requirements applicable to attic ventilation. If not measure the size yourself. 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.

Hence you would need two square feet 600 300 of attic 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. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. A ridge vent is a ventilation strip that is placed along the ridgeline of the home.

The two square feet is divided equally between the intake and the exhaust one square foot for each. The building code lets you reduce that by half under some conditions but more roof ventilation is usually better. How does roof pitch come into play when calculating attic ventilation current irc requirements do not factor the role a roof s pitch plays in the amount of attic ventilation needed but ventilation manufacturers do. Standard attic vents like af 50 s ventilation fans or solar powered attic fans.

Code requirements the international building code. Calculating attic ventilation requirements. Then aim for about 1 sq. It is important that air movement occurs and is not impeded by any framing members of the.

The ridge vent is installed on the peak with nails and shingled over for aesthetic purposes. 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. 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. Enter square footage calculate or enter the square footage of the attic or area to be vented.

Intake vents located at the lowest part of the roof under the eaves allow cool. Ridge vents are one of the easiest ways to meet roof venting requirements. 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. Divide the square footage item 1 by 300.

Foot of ventilation for every 150 sq. The roofing industry also has practical guide lines for attic ventilation. The open area of a vent is sometimes listed on the roof air vent as nfva net free vent area. Generally as the roof pitch increases the volume inside the attic also increases along with the amount of needed.

Other options to meet your attic ventilation needs are.