A carpenter is preparing to install rigid insulation over the exterior sheathing of a house before applying siding. The local building code requires a continuous air barrier. What is the most effective method to ensure the rigid insulation also functions as a part of the continuous air barrier assembly?

Question: A carpenter is preparing to install rigid insulation over the exterior sheathing of a house before applying siding. The local building code requires a continuous air barrier. What is the most effective method to ensure the rigid insulation also functions as a part of the continuous air barrier assembly?

Answer options:

• Overlap the joints of the rigid insulation by at least 50 mm. ✅ Apply tapes and sealants to all joints and penetrations of the rigid insulation.
• Fasten the rigid insulation with extra nails to prevent air movement.
• Install a separate sheet of polyethylene over the rigid insulation.

Correct answer: Apply tapes and sealants to all joints and penetrations of the rigid insulation.

Explanation: For rigid insulation to function as an effective air barrier, all joints, edges, and penetrations must be sealed with appropriate tapes and sealants. Overlapping joints is insufficient on its own, extra fasteners don't create an air seal, and a separate poly sheet would be redundant if the rigid insulation itself is acting as the air barrier.