3.1003.1 New Ceiling Below Original—Old Ceiling Intact or Repairable

Topic: 
Attics
Subtopic: 
Dropped Ceilings and Soffits
Desired Outcome: 
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 prevents air leakage and moisture movement between the attic and conditioned space
TitleSpecification(s)Objective(s)
3.1003.1a
Pre-inspection

An inspection will be conducted for mold, water leaks, and water damage before sealing a dropped ceiling or soffit

Repairs will be completed before work begins

Repair moisture-related issues

3.1003.1b
Sealing methods

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 in line with the ceiling level

Material will be cut to fit and fastened as required

OR

Side of stud bays will be sealed 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 from bottom of dropped ceiling to top-plate

OR

Wall below openings will be dense packed

OR

Wall below openings will be bridged and sealed with SPF SPF Spray polyurethane foam

Seals will be used that prevent visible air movement using chemical smoke at 50 pascals of pressure difference

Prevent air leakage from dropped ceiling to attic

3.1003.1c
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

3.1003.1d
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

3.1003.1e
Adjacent framing

All remaining gaps will be sealed at the top of the dropped ceiling

OR

All remaining gaps at the top of the chase will be sealed

Provide airtight framing from one finished side of the dropped ceiling to the other