3.1002.2 Stairwell to Attic—Door at Bottom with No Ceiling Above

Topic: 
Attics
Subtopic: 
Open Stairwells
Desired Outcome: 
Stairwell sealed to prevent air leakage and moisture movement between the attic and the conditioned space
TitleSpecification(s)Objective(s)
3.1002.2a
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

3.1002.2b
Option 1: bring stairwell inside

Materials will be installed in line with the ceiling level with an airtight and operable insulated panel weighing no more than 15 pounds, or a pre-fabricated kit may be used for repeated access

OR

Airtight seal will be provided between level of new closure or cap and interior ceiling around perimeter

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

Prevent air leakage through stairwell between conditioned space and attic

Ensure the insulated panel is lightweight and easy for the occupant to use on an ongoing basis

Support insulation

Bring the stairwell inside of the thermal boundary Thermal boundary The separation between the interior and exterior environments of a building that slows heat flow

Ensure the new closure ties into the existing 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 on all sides

3.1002.2c
Option 2: keep stairwell outside

An 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 created and insulation material will be continuously installed across all surfaces of stairwell, including weather-stripped and insulated doors

OR

All cavities between stairs and conditioned space will be insulated and tested to resist air flow (e.g., walls, floors, landings, under stairs)

Door will be weatherstripped and insulated

OR

A combination of the above methods can be used

Prevent air leakage

Provide continuous thermal boundary Thermal boundary The separation between the interior and exterior environments of a building that slows heat flow

Maximize thermal performance

3.1002.2d
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

3.1002.2e
Joint seal

Continuous, airtight seals will be provided around seams, cracks, joints, edges, penetrations, and connections

Provide airtight, durable seal that does not move, bend, or sag

3.1002.2f
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 from 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