Attic Vent Insulation Requirements

The roofing industry also has practical guide lines for attic ventilation.

Attic vent insulation requirements.

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. 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. For the same reason insulation shouldn t touch the roof s underside. Roof insulation thermal resistance at roof perimeter should be equal or greater to thermal resistance of exterior wall.

Whole house fans powered attic fans. 1 300 ventilation ratio recommended. The airflow from the soffits to the ridge vent keeps the roof cool and prevents ice dams and the material will block that flow. The majority of the requirements related to attic ventilation have not changed much from the previous editions.

Fans and vents may be installed on the roof system that will draw the air out of the. Typically building codes include minimum requirements applicable to attic ventilation. The following are the requirements taken directly from the irc. Good roof ventilation can do this but shingle color sun exposure and insulation are exponentially more important to overall energy efficiency than ventilation.

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 ventilation amount and opening size requirements can be found in section 806 roof ventilation of chapter 8 roof ceiling construction. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. Attic ceiling to stop airborne moisture from reaching a cold surface and condensing inside the building envelope in this design insulation effectively separates the interior and exterior spaces while slowing down moisture flow so the dewpoint is not achieved within.

Enter square footage calculate or enter the square footage of the attic or area to be vented. 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. Code requirements the international building code. 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.

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.