Sweating duct work

[shawncone]

Help! I have a ventilated crawlspace that has a new 6mil liner over the dirt. Everything was fine until it got warm and we started using our air conditioner. All the duct work for the house is in the crawlspace, and the ducts are "sweating" the condensation onto the new liner. Any thoughts on correcting this? Thanks, Shawn.

[Crawl Space MD]

Shawn,
This is a common problem with vented crawl spaces. Vented dirt crawl spaces are bad enough, then you add an A/C system and the problem gets worse.

Call your local Basement Systems - CleanSpace Dealer for a free inspection.
Thank you.
Crawl Space MD

[chumpchange]

First, 6 mil poly is not a sufficient vapor barrier. Poly only gets good on vapor at 10mil. Double layered 6 mil poly with taped seams and good overlap will work also. Second, you probably have crawl space vents that let moist air in. Third, are your ducts insulated? If so, the insulation was improperly attached or imporoperly specified, or both.

The ducts must be insulated to an R value that corresponds to ensuring dew point is not reached on the outside of the insulation. The insulation must have a vapor proof outer layer that is properly sealed so no airborne water vapor can reach the duct.

[Crawl Space MD]

Hi,
You may have open vents, which will need to be closed. BUT ONLY after you have had an expert give an informed prescription for wellness. Your crawl space is sick, and needs to be repaired. If you had a leaking roof, you would have a roofer fix it. Please have one of our certified crawl space repair companies come out and give you a crawl space solution that will last for years. We have many patented solutions for crawl space reair including sump pumps, dehumidifiers, vent covers, EverLast crawl space doors etc. You can find a contractor near you on our website.
Thank you.
Crawl Space MD