3.1002.1 Interior with Sloped Ceiling

Topic: 
Attics
Subtopic: 
Open Stairwells
Desired Outcome: 
Stairwells sealed to prevent air leakage and moisture movement between the attic and conditioned space
For supporting material, see Referenced Standards and Calculation of the Infiltration Credit.
TitleSpecification(s)Objective(s)
3.1002.1a
Pre-inspection

An inspection will be conducted for mold, water leaks, and water damage before sealing an open stairwell

Repairs will be completed before work begins

Repair moisture-related issues
3.1002.1b
Standard void over stairwell (15-minute fire-rated material; e.g., gypsum lined)

Entire opening will be spanned with rigid material Rigid material Drywall, oriented strand board, duct board, cardboard, or any other stiff product that may support the load of insulation while serving as a durable air barrier

Material will be cut to fit and fastened as required

Prevent air leakage from wall to attic

Reduce opening to what can be sealed with sealant

Support load as required (e.g., wind, insulation)
3.1002.1c
Non-standard void over stairwell (surfaces around void are not 15-minute fire-rated (e.g., bookcases, chest of drawers), or lined with paneling

Material will be used that can be exposed to the interior of the house

Prevent a fire hazard
3.1002.1d
Support

Support material Support material Typically, wooden strips that provide support over holes greater than 24" in size for less rigid air barrier materials will be installed for spans wider than 24", except when air barrier Air barrier The separation between the interior and exterior environments of a building that slows air flow to the point that no smoke movement is visible at 50 pascals of pressure difference across the boundary material is rated to span greater distance under load (e.g., wind, insulation)

Ensure seal stays in place and does not sag
3.1002.1e
Joint seal

Continuous seal will be installed around seams, cracks, joints, edges, penetrations, and connections

Provide airtight, durable seal that does not move, bend, or sag
3.1002.1f
Perimeter sealing

Air barrier Air barrier The separation between the interior and exterior environments of a building that slows air flow to the point that no smoke movement is visible at 50 pascals of pressure difference across the boundary will be extended on all four sides from finished ceiling or existing framing to the new barrier

Access will be gained as needed (e.g., pull flooring)

Create a continuous air barrier Air barrier The separation between the interior and exterior environments of a building that slows air flow to the point that no smoke movement is visible at 50 pascals of pressure difference across the boundary