Attic Vent Insulation Requirements

Good roof ventilation can do this but shingle color sun exposure and insulation are exponentially more important to overall energy efficiency than ventilation.

Attic vent insulation requirements.

1 300 ventilation ratio recommended. Intake vents located at the lowest part of the roof under the eaves allow cool. Fans and vents may be installed on the roof system that will draw the air out of the. The roofing industry also has practical guide lines for attic ventilation.

Covering up the soffit vents with loose fill or batts which can happen if you stuff insulation along the eaves is a huge no no. For the same reason insulation shouldn t touch the roof s underside. Proper attic ventilation can be an impor tant performance consideration when design ing and installing steep slope roof systems. Whole house fans powered attic fans.

Roof insulation thermal resistance at roof perimeter should be equal or greater to thermal resistance of exterior wall. Enter square footage calculate or enter the square footage of the attic or area to be vented. 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.

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. 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. Code requirements the international building code. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents.

In addition insulation baffles must be installed at the point where the attic floor meets the roofline to prevent the attic insulation from migrating into the cavities and restricting the airflow from the soffit vents. The airflow from the soffits to the ridge vent keeps the roof cool and prevents ice dams and the material will block that flow. Typically building codes include minimum requirements applicable to attic ventilation. Sure installing roof vents for older homes can reduce your hot air during the summer but there are probably more low risk cost effective ways to increase your home s energy.

Unvented attic assemblies unvented attics rely on an air impermeable insulation installed to the roof deck s underside i e. The ventilation amount and opening size requirements can be found in section 806 roof ventilation of chapter 8 roof ceiling construction.