Which statement is true about air sealing and insulation sequencing?

Which statement is true about air sealing and insulation sequencing?

• A. Air sealing must be done before insulation.
• B. Insulation must be done before air sealing
• C. They can be done in any order
• D. They are unrelated

Answer: (A)

Air sealing should be done before insulation to maximize energy efficiency and ensure the insulation can perform as designed. When you seal leaks, gaps, and penetrations first, you stop most of the air from moving through the building envelope. That means heat loss or gain isn’t bypassed by air leaks, drafts are reduced, and moisture-laden air doesn’t bypass the insulation layer. If you insulate first, air can still flow through those leaks, which can carry heat with it, bypass the insulation, and compromise moisture control and comfort. Sealing first also makes it easier to identify and fix every leak and prevents insulation from being compressed or bypassed by air movement. So, the best practice is to seal the building envelope before adding insulation.

Air sealing should be done before insulation to maximize energy efficiency and ensure the insulation can perform as designed. When you seal leaks, gaps, and penetrations first, you stop most of the air from moving through the building envelope. That means heat loss or gain isn’t bypassed by air leaks, drafts are reduced, and moisture-laden air doesn’t bypass the insulation layer. If you insulate first, air can still flow through those leaks, which can carry heat with it, bypass the insulation, and compromise moisture control and comfort. Sealing first also makes it easier to identify and fix every leak and prevents insulation from being compressed or bypassed by air movement. So, the best practice is to seal the building envelope before adding insulation.