You may need an architect and/or engineer to help you with this. My guess is the best thing you could do is to tear out the old stuff and go a little deeper. There is a great benefit to having a basement with accessible space between the ceiling and the floor above. That means at least nine foot high foundation walls, probably higher. If you post the location, someone familiar with the jurisdiction could may be able to offer more concrete (pun intended) guidance. My wild guess DC suburbs. How'd I do?

Yahoo or Google would be a good place to start.

Properly installed ducts will not sweat regardless of how humid surrounding air is. One red flag in your discription is "cheap tape was used". Flex duct is best secured with Zip-ties. The linner is normally taped to boot then insulation and outside cover pulled over linner and secured with Zip-tie. If you reconnect ducts to boots,buy the special tensioning tool to pull Zip-ties tight. It sounds like conditioned air is finding it's way out of the spirial wire linner then flowing against outside cover. There might be holes in linner or linner might be disconnected from boots. Another possibility is that duct is simply not well enough insulated.

We bought this house about a year and a half ago. At the time we bought it, we saw pictures from the home inspector that show that the crawlspace is encapsulated - so far so good. But we had a recent plumbing issue, and now I have become aware that we *also* have a dehumidifier and condensate pump down there. The problem is this - I see no evidence that the thing is actually running. I placed a beer cup beneath where the tube from the pump exits the foundation, and it isn't catching anything. And it is clear that typically one should have these things serviced from time to time (clean filter, etc, etc). Not unlike having HVAC serviced, I guess.. Pictures of the current install below. An unidentified dehumidifier with what looks like a Little Giant condensate pump. I haven't been able to ID the dehumidifier just from the pictures. The dehumidifier and pump are just sitting on the plastic - not elevated in any way. I called a crawlspace company to come out and check things out - they can't get here for a couple of weeks however, so none of my questions have been answered as of yet. It is the same company that did our neighbor's house - they were happy with the work. Anyways there are a couple of issues on my mind: Why is it that the dehumidifier and/or condensate pump isn't running. I am guessing GFI got tripped, but that's a guess at the moment. Is there a way to do this so that a GFI trip doesn't require someone to go into the crawlspace to reset the thing? Or to at least get a notification of *some* sort so you don't go for months and months with the thing not even running. How old is the current dehumidifier, and is it even the right tool for the job. It isn't one of those modern box-shaped ones that is typically hung from the floor joists - it looks like an upright model of some sort. So I am wondering if we should just be prepared to discard this one and replace it. It is sort of musty down there (with a sort of cat pee odor). And I see that modern encapsulations these days will tend to have one automated vent to help control this problem. But if we get the dehumidifier working again, does that go away, or do we need something else? Is there anything else I should be asking the crawlspace company? Does anyone have any idea what brand the dehumidifier is, and roughly how old it might be?