All joints cracks and penetrations in the wall air barrier shall be fully sealed with caulk foam or equivalent.
Fully sealed attic.
Seal the attic access.
Cut 1 3 boards to fit the perimeter of the opening and nail them on with 6d finish nails.
However if moisture is able to enter the unvented attic space it may lead to roofing panel issues.
Apply self adhesive foam weatherstrip tape to the top edge of the stop.
The number one prep step.
The energy savings touted by unvented attics can be as high as 20.
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.
Weatherstrip the attic access hatch or door.
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.
Find a diagram of common air leaks here here s a quick primer on fixing draft prone spots.
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.
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.