3.1001.2 Chase Capping

Topic:

Attics

Subtopic:

Penetrations and Chases

Desired Outcome:

Chase capped 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.

Single-Family Homes

	Title	Specification(s)	Objective(s)
	3.1001.2a Pre-inspection	An inspection will be conducted for mold, water leaks, and water damage before sealing a chase Repairs will be completed before work begins	Repair moisture-related issues
	3.1001.2b Standard chase (interior walls covered with drywall or plaster)	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	Reduce opening to what can be sealed with sealant
	3.1001.2c Non-standard chase (interior walls covered with wood or paneling)	Material will be used that can be exposed to the interior of the house and meet the flame and smoke spread indexes as required in 2012 IRC IRC International Residential Code R302.9	Prevent a fire hazard
	3.1001.2d 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
	3.1001.2e 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
	3.1001.2f Adjacent framing	All remaining gaps at the top of the chase will be sealed	Ensure airtight seal from one finished side of the chase to the other