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

• A. Seal gaps 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 are sealed

Answer: (D)

The main idea here is keeping the air barrier continuous around every penetration to stop air leaks. Penetrations are potential leak points, so you treat the edges where they meet the barrier to maintain an unbroken airtight path.

Sealing gaps with caulking or expanding foam directly fills the voids between the penetration and the surrounding surface, preventing air from bypassing the barrier at those gaps. Using a manufactured boot or gasket provides a purpose-built seal interface that fits snugly around the penetration, maintaining continuity where the barrier meets the opening. Constructing a gasket from polyurethane and acoustical sealant offers another way to bridge irregular gaps and create a tight seal at the interface, keeping the barrier continuous.

Installing the air barrier after penetrations are sealed isn’t a technique for continuity because the barrier itself must form the continuous envelope, with penetrations sealed into that barrier. Putting the barrier on after the penetrations are already sealed can compromise the bond, create gaps, or allow air to bypass the barrier, so it doesn’t reliably maintain airtight continuity.