Green Building How To Build A Conditioned Attic

The attic space becomes indirectly conditioned as a result of the air leakage heat transfer and.

Green building how to build a conditioned attic.

In warmer climates unvented attics can prevent the condensation that occurs on ductwork in some vented attic spaces. Department of energy through the building america program to research conditioned attics in nevada and texas. The irc has permitted unvented conditioned attics since 2006 with certain requirements. 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.

You can reduce dust buildup using an unvented attic versus a vented attic. This has several advantages including less air transfer and what air does transfer is conditioned. Code requirements vary across the country. 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.

After experimenting with cellulose insulated roof assemblies and fiberglass insulated roof assemblies lstiburek began promoting conditioned attics. The acceptance of unvented conditioned attics continues to grow among builders and building officials. During the 1990s the building science corporation received funding from the u s. Watch this if you ve not seen it.

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. 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. 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. In a roof attic assembly the builder has two choices.

The roof deck in an unvented attic must be exceptionally airtight.