Green Building How To Build A Conditioned Attic

You can reduce dust buildup using an unvented attic versus a vented attic.

Green building how to build a conditioned attic.

5 dumb ways to build in the south. The irc has permitted unvented conditioned attics since 2006 with certain requirements. 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. In a roof attic assembly the builder has two choices.

Department of energy through the building america program to research conditioned attics in nevada and texas. Watch this if you ve not seen it. 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. 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.

My original plan was to build a conditioned attic and place 1 5 of foam xps board r7 5 installation on top of the roof deck and fill the old true 2x4 rafters and rafter walls with closed cell insulation and if able attach 3 of foam xps board r15 to the rafters in the attic. In warmer climates unvented attics can prevent the condensation that occurs on ductwork in some vented attic spaces. 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 acceptance of unvented conditioned attics continues to grow among builders and building officials.

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. The roof deck in an unvented attic must be exceptionally airtight. The attic space becomes indirectly conditioned as a result of the air leakage heat transfer and. During the 1990s the building science corporation received funding from the u s.

Code requirements vary across the country.