What is the first step in the recommended order of operations when upgrading insulation in a wall assembly?

• A. Identify and seal air leaks
• B. Install vapor retarder in correct location
• C. Install insulation
• D. Install interior finish

Answer: (A)

Identifying and sealing air leaks is the first step because air movement through a wall bypasses insulation and carries heat and moisture with it. By locating gaps around penetrations, outlets, joints, rim joists, and other openings and sealing them, you stop drafts and create a tighter, more predictable thermal boundary. This makes the insulation more effective and helps moisture management, since less humid indoor air can infiltrate the wall cavity. With the leaks addressed, you can place the vapor retarder in the correct location for the climate, then install insulation, and finally finish the interior.