Which of the following is NOT a technique to ensure the continuity of the air barrier around service penetrations?

• A. Seal the gap in the air barrier with caulking or expanding foam
• B. Use a manufactured boot or gasket
• C. Construct a gasket out of polyurethane and acoustical sealant
• D. Install an air barrier after penetrations sealed

Answer: (D)

Maintaining airtight continuity around penetrations relies on detailing that integrates the barrier with the openings so air can’t bypass it. Filling the gap where a pipe or conduit passes through with caulking or expanding foam closes the voids at the interface, preventing leaks at that junction. A manufactured boot or gasket provides a defined, tight boundary around the penetrating object and ties into the air barrier plane, preserving continuity even with irregular shapes. Building a gasket from polyurethane and acoustical sealant can achieve a flexible, durable seal at the penetration edge, keeping the barrier airtight where it meets the wall or roof surface.

Installing the air barrier after the penetrations have already been sealed doesn’t fit as a method to ensure continuity because the barrier needs to be applied as a continuous plane that intersects and seals at penetrations. Sealing first and then laying the barrier can compromise the seal or create gaps, undermining the airtight connection. The correct approach is to detail the penetrations into the barrier during installation, using seals, boots, or gaskets so the barrier remains continuous.