RCD #6 Mastic (11 oz)

Sealing heating/cooling ducts dramatically improves the efficiency of heating distribution systems. Unsealed ducts typically leak about 10-15% of conditioned air. Leaky ducts can pull unwanted air into the conditioned parts of your house and create pressure differentials within the house, increasing air infiltration and exfiltration problems. Mastic is a fibrous adhesive sealant used for coating of thermal insulation on pipes and ducts, and for sealing of un-insulated ducts. Use with a caulk gun. Non-toxic, non-flammable and dries to the touch in 30 minutes.