I just bought a house whose crawlspace looks like it was partially converted to being sealed off. Basically, they put down a vapor barrier and closed off the vents, but didn't finish the job. On top of that, there's a PVC pipe from the furnace dripping what I assume is condensation onto the plastic, and that's what I'm here to ask for advice on.

The wood down there seems like it's in good shape now, but I'm trying to avoid future damage. I talked to a couple inspectors about the crawl space prior to buying the house, but I'm trying to figure out which of their suggestions I should go with. The easy solution is to undo what's been done with it and tear up the plastic, or at least cut a hole underneath where it drips, and let it drip into the gravel. The other recommendation was to run the pipe off somewhere else or to join it to the house's sewage drain.

You can see about all there is to see in these two photos. The short pipe in the second picture is dripping down the insulated pipe coming off the air conditioning unit and onto the plastic. It's a pretty steady trickle when the AC's running.

Crawlspace Photo 1

Crawlspace Photo 2

In addition to this, I do need to re-open the vents (I was told they were re-opened before we closed on the house but they look closed to me) and re-insulate the AC pipe, but that all sounds straightforward.

Any advice on what to do here would be appreciated. I can try to provide more info or details if needed. Thanks!

  • You are correct in that you don't want this dripping this way. I suggest that you'll want to plumb this drain so that it empties into an actual drain. If water is left to collect on its own somewhere, the amount of water that is generated will almost certainly cause some sort of problem.
    – jwh20
    Aug 5, 2019 at 18:49
  • What's happening to the joist between the two PVC pipes? Has it been cut, or snapped and moved out of position?
    – Phil G
    Aug 5, 2019 at 18:54

1 Answer 1


The short pipe looks like it's a condensate drain - which will trickle when the AC is operating. It needs to run to a drain or to the outside. It looks like the insulation over the pipes has been damaged by the condensate running over it, and will need to be replaced. Even if the drain wasn't running onto them, the pipes are cold, so will sweat unless they're well insulated - the C shaped insulation needs taping closed, or you can buy insulation with a ziploc type feature that closes it up.

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