: : : : Background: The last 5-7 feet of my dryer venting goes through unheated airspace in my ceiling where it finally exits at the roof vent. Condensation within the venting is causing water to drip at the 90 degree elbow about 3 foot below the roof vent. The water drippng can be heard for awhile, but stops after about 15-20 minutes of dryer time. I removed a light fixture nearby to verify that the drips occur from the lower elbow seam. I placed some foil/rubber seal tape along the bottom half of the seam since that's as far as I could reach. The drips still occur. The vent cap on the roof is of a standard design: about 12 inches in diameter having a ^ shape, but flatter. The dryer venting was recently cleaned by a chimney sweep. He removed a lot a lint. Most of it was damp which had clogged the venting. He also said it could take a few days/dryer cycles to remove ant remaining moisture in the venting. Thanks for your advice. Dan
: : : DAN: The ONLY way to eliminate this condensation problem is to INSULATE the VENT wherever it passes through the UNHEATED area. There is a (THERMAL)fibreglass blanket with a foil backing that can be wrapped and taped at the joints. Seal all joints neatly and carefully. Also, this rain cap that you describe is not the type for this appliance, because the moisture collects on the top and falls back down the pipe and can cause water damage. Good luck, Hube
: : : Hube: What type of rain cap design would minimize the formation of water droplets? Thanks again!
: The best one is one that turns down at least 90 Degrees at its termination point, thus expelling any "beads", etc of major condensation. The PEAK cap that you describe is for smoke, fumes, etc, which have no condensation effect. Also, Do you have a "backdraft" damper at the termination point of this vent? ... Hube

:No damper that I am aware of. Th chimney sweep cleaned the venting without having to remove a damper. I have seen this "upside down J" vent before, but not here in the southwest. I'll look for one this weekend. I think that will help a lot. Appreciate your input. Dan :)