Green Building How To Build A Conditioned Attic

In an unvented attic assembly air impermeable insulation is applied directly to the underside of the structural roof deck and is tied into the insulation located in the walls so that the roof system becomes part of the insulated building enclosure.

Green building how to build a conditioned attic.

The loss of energy efficiency means some designers choose to move the ductwork into the conditioned areas of the home and leave the attics unvented. The irc has permitted unvented conditioned attics since 2006 with certain requirements. Unvented attics are built with insulation of the attic is placed at the roof level and the area inside the attic is a conditioned space. The roof deck in an unvented attic must be exceptionally airtight.

Code requirements vary across the country. 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. During the 1990s the building science corporation received funding from the u s. This has several advantages including less air transfer and what air does transfer is conditioned.

Watch this if you ve not seen it. In warmer climates unvented attics can prevent the condensation that occurs on ductwork in some vented attic spaces. 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. After experimenting with cellulose insulated roof assemblies and fiberglass insulated roof assemblies lstiburek began promoting conditioned attics.

5 dumb ways to build in the south. In a roof attic assembly the builder has two choices. The attic space becomes indirectly conditioned as a result of the air leakage heat transfer and. The thermal boundary can be at the ceiling plane leaving the attic space above uninsulated and vented or the thermal boundary can be located at the roof line creating a sealed insulated conditioned or semi conditioned attic space.

Department of energy through the building america program to research conditioned attics in nevada and texas.