What is the purpose of air sealing tapes and sealants in the building envelope?

• A. They seal only around doors.
• B. They provide decorative finishes to walls.
• C. They seal joints and penetrations to reduce infiltration and improve energy efficiency when used with a continuous air barrier.
• D. They are used to waterproof the roof deck.

Answer: (C)

Air sealing tapes and sealants are used to seal joints and penetrations in the building envelope to stop air leakage and support energy efficiency when used with a continuous air barrier. Gaps around seams, around windows and doors, at roof and wall penetrations, and where utilities pass through are paths for conditioned air to escape or unconditioned air to enter. Sealing these paths reduces infiltration, lowers heating and cooling loads, improves occupant comfort, and helps keep the indoor environment stable. These products are intended for airtight assemblies and must be compatible with the materials and exposure conditions; they are not just decorative, nor are they a substitute for roof deck waterproofing.