How to Seal the Ends of Duct Work
Duct sealing is essential in a home-heating system to keep it as energy efficient as possible. Without proper duct sealing, air will leak out of the duct work at the seams and joints. If this air leaks out in places like an attic or wall space, condensation can form. This condensation can cause mold and mildew problems. All of this is preventable when you seal the ends of duct work. Does this Spark an idea?
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Things You'll Need
- Water-based mastic (caulk tube or bucket)
- Caulk gun or paint brush
- Aluminum foil tape
Instructions
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Instructions
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1
Remove any items that are around the duct work. You'll want full access to the duct work to seal it properly .
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2
Turn off the power to the HVAC system. If the system turns on when sealing the duct work, the air pressure can blow out the sealant before it cures.
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3
Apply a water-based mastic over all the seams and joints of the duct work. Look for a UL-181 mastic as these are more flexible, longer lasting and stick to the ducts well. The ends are especially important since this is where most of the air will leak out if not properly sealed.
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4
Allow ample drying time before turning the HVAC system back on. When the mastic is fully cured, turn the power back on to the HVAC system. Your duct work system is now properly sealed.
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Tips & Warnings
In lieu of mastic, you may apply aluminum foil tape. This provides an instant seal and you don't need any cure time before turning the HVAC system back on.
Do not use duct tape. This fabric tape will dry out, crack and fall off.
