Duct work conducts cool air during the hot months of summer and warm air during the cold of winter. These ducts are concealed above your ceiling and inside of your walls. When cool and warm air collide, the surfaces in this area become coated with a thin layer of condensation. The condensation on your duct work will be pulled along the metal surface and follow the path of least resistance. This path leads down and eventually ends at your vents. Cleaning and insulating your ducts will eliminate the problem of leaking vents.
Caulk gun loaded with 30-year silicone caulk
Disposable protective suit
Enter the attic space of your house. Inspect the roof for leaks to rule out that possibility for your moisture problem. Inspect the duct work for damage that must be repaired before continuing.
Clean and dry the duct work with rags. Wipe away all of the dust, moisture and debris from every side of the ducts to prepare the surfaces for insulation.
Wrap ducts with R-19 insulation. Cut the insulation with your shears to fit the duct work. Fasten the insulation to the ducts with a solid layer of duct tape.
Use your caulk gun to seal the seams between the leaking vent and the ceiling from the attic. Smooth the caulk with a wet rag. Seal the leaking vent with caulk from inside of the room after wiping the vent with a dry rag. Cover every seam around the vent and wipe the caulk smooth with a wet rag.
Place a drop cloth at the beneath the entrance of the attic to prevent insulation fibers from entering the living space in your home.
Seal roof leaks with your caulk gun.
Spraying the inside of your roof with spray on insulation and placing new R-19 roll insulation between the trusses will help prevent your ducts from condensation.
Always wear a respirator, safety glasses, work gloves and a disposable protective suit when working with insulation.