Items to Avoid

• Do not use this air sealing procedure for vents that exhaust air from combustion appliances, or if you are unsure of what the duct is exhausting.

Items to Incorporate

• Ensure the outside of the exhaust duct is sealed, insulated, and is not collapsed, throughout the whole attic space.
• Ensure the spray foam or sealant at the ceiling penetration is even and continuous to create an airtight seal.
• Ensure connection of the duct to the exhaust boot or vent hood is properly sealed.