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Groundwater in A/C Vents Under Concrete Slab

I have a two-story townhouse condo built on a slab. The first-floor forced-air ducts run under the slab. The runs are 8" PVC pipes but the turns are actually round sheet metal. They were not made water tight. In times of heavy rain, ground water seeps into the ducts. I have attempted to seal the joints I could reach but there is one joint around a corner that I cannot reach.

I took a picture with my phone but can not upload it or post a link to my Dropbox. I cannot yet prove that the water is coming from around the bend. When the level drops, I should be able to dry it and then watch where it comes in from.

Does anyone have any suggestions how I can seal that joint? I would really (REALLY) like to avoid jackhammering through the slab.

Re: Groundwater in A/C Vents Under Concrete Slab

You obviously have a problem here, and replacing the fittings is what you need to do.

Find out if this is the HOA responsibility or if the place is under warranty.

Re: Groundwater in A/C Vents Under Concrete Slab
dj1 wrote:

Find out if this is the HOA responsibility or if the place is under warranty.

Oh if it were that easy. I could list numerous things about which I am unsatisfied with our HOA. The one pertinent to this discussion is that the by-laws were amended to exclude all HVAC work including all ductwork above and below ground. In other words, the first time someone went to the HOA about something like this, they had to do something. So they did: they washed their hands of the whole thing. I talked to my neighbors and I know that this problem is endemic to the condos in the neighborhood.

So on this one, I'm on my own. As are all my neighbors.

There is no damage to my home when this happens. There is more moisture in my condo, of course. This time, it was so high that when the A/C ran the waves would close off the duct and make really bad gurgling sounds. So we don't run the A/C which is unfortunate because it was 21ºF in Chicagoland last night. Directing the flu upstairs works to heat the upper floor and a space heater is relatively sufficient for the first floor when we're home.

We are looking to move. Hopefully this summer. I don't think I can sell the place like this. I'd probably have to declare this to the buyer which would probably scare people away. So I'm most likely going to have to break into the slab and get at it directly.

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