Unvented Attic Section

For unvented attics having the spray foam layer applied continuously from the roof wall intersection to the roof peak at the specified thickness encapsulating the entire interior surface area of the attic will hinder airborne moisture entry while providing an energy efficient environment.

Unvented attic section. This section outlines the conditions for unvented attic roof assemblies. No interior vapor retarders are installed on the ceiling side attic floor of the unvented attic. The unvented attic space is completely within the building thermal envelope. Section 1203 3 says unvented attics where ceilings are applied directly to the underside of the roof framing members are permitted when all of the following conditions are met.

Install insulation along the underside of the roof deck of an unvented attic rather than on the ceiling deck of a vented attic for either of two reasons. The unvented attic space is completely within the building thermal envelope. This section indicates that ventilators for roofs are to be installed in accordance with manufacturer s installation instructions and the requirements of section r903. Section r806 4 installation and weather protection.

To provide an unvented conditioned space for locating hvac equipment in the attic and or to provide a continuous thermal barrier for designs that have complex coffered ceiling planes and or numerous penetrations for lights speakers vents soffits etc which make it difficult to achieve an airtight ceiling plane. However if moisture is able to enter the unvented attic space it may lead to roofing panel issues. Where wood shingles or shakes are used a minimum 1 4 inch 6 4 mm vented airspace separates the. The energy savings touted by unvented attics can be as high as 20.

2009 irc section r806 4. The unvented attic space is completely within the building thermal envelope. Requirements for unvented attic assemblies are provided in section 0806 4 of the international residential code 2009 irc. The unvented attic space is completely contained within the building thermal envelope 2.

Unventilated attics can help to mitigate energy loss through leaky ducts or ceiling fittings. No interior class i vapor retarders are installed on the ceiling side attic floor of the unvented attic assembly or on the ceiling side of the unvented enclosed roof framing assembly. 2012 irc section r806 5 unvented attic assemblies unvented attic assemblies spaces between the ceiling joists of the top story of the roof rafters shall be permitted if all of the following conditions are met. No interior class i vapor retarders are installed on the ceiling side attic floor of the unvented attic assembly or.

The unvented attic space is completely within the building thermal envelope.