Fully Sealed Attic

Wall frames are hollow letting air flow freely between the walls and up into the attic.

Fully sealed attic.

Sealed attic construction by excluding vents to the exterior can be a good way to exclude moisture laden outside air from attic and may offer a more easily constructed alternative for air leakage control at the top of residential buildings. Attic insulation shall be installed at all flat and sloped surfaces adjoining the conditioned space with less than 2 gaps voids and compressions and at levels that meet or exceed prescriptive levels specified by the 2012. All joints cracks and penetrations in the wall air barrier shall be fully sealed with caulk foam or equivalent. Sealed and insulated the attic hatch helps keep heat in.

Jump ducts which do not directly deliver conditioned air from the hvac unit may be located in attics if all joints including boot to drywall are fully air sealed with mastic or foam and the jump duct is fully buried under the attic insulation. Unventilated attics can help to mitigate energy loss through leaky ducts or ceiling fittings. Find a diagram of common air leaks here here s a quick primer on fixing draft prone spots. A fundamental requirement of an unvented attic assembly is the use of air impermeable insulation on the underside of the unvented roof to prevent air infiltration and exclude airborne moisture from the attic.

A fully insulated attic helps your house regulate temperature and airflow. The attic space becomes indirectly conditioned as a result of the air leakage heat transfer and vapor diffusion through the ceiling. Gaps in the attic or between the lower floors and the attic will let heated or cooled air escape to the great unconditioned outdoors making any insulation you add essentially useless. It also prevents unwanted critters like raccoons from moving in.

The number one prep step. The energy savings touted by unvented attics can be as high as 20.