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Location: Sometimes Maryland, sometimes NoVA. Depends on the day of the week
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This is an oversized one-car garage where we converted about 1/3 of the area to a finished laundry room. I have attached a rough sketch-up. The green area is VCT, the gray area is plain concrete floor. The blue area is where we have noticed some water. Inside the laundry room, it bubbles up between the tiles (but is not on top of the tiles). Just outside the door of the laundry room, the concrete is damp.
Data points:
(1) Nothing (washer, sink, well lines) appears to be leaking on top of the VCT
(2) There is condensation on the lines leading to the pressure tank
(3) We had 8.5 inches of rain in May. April and May rainfall totals were the second highest since 1889
(4) The sump pump is working, not overflowing, and directs far away from the house.
(5) We lived in the house for a year before covering the floor and never saw any evidence of dampness, especially not in the middle of the floor.
(6) The main drain line for the house runs parallel to and under the wall on the right in the picture.
(7) For some messed up reason, the grading on the slab runs down and to the right (as shown in the picture) - not to the sump pump. We discovered this one vacation about 2 years ago when the washer filled and overflowed while we were gone. We now turn it off when we leave for a couple of days
(8) There is no moisture on the slab near the sump or pressure tank, other than a couple of drips of condensation, but not enough to puddle or run.
Hypothesis: Could the heat from the freezer be doing something to bring up moisture through the slab?
More likely you have a broken or damaged pipe somewhere in the slab, or a leak that is somehow getting between the slab and covering. Used to have a similar problem when the AC condensate drain got plugged and the water would sneak down the inside of the plenum and under the tiles in the laundry area of our garage. A quick release of the snot via a wet vac, and infusion of bleach solved our problems until the next time.
Location: Sometimes Maryland, sometimes NoVA. Depends on the day of the week
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Quote:
Originally Posted by BigDGeek
I agree with the first response, it sounds like a leak.
You agree with "leak inside the slab"? But the only pipe in the slab is at least 6 feet away, and its an unpressurized sewer drain. I had it scoped back in Dec and the part in the slab was fine then (should probably consider replacing the 10' line between the house and the septic tank). How could a leak in the sewer line cause water to come up through the slab, rather than percoluating down? Additionally, the spot did not dry out when we were gone for 10 days, which, if it were a sewer line, should have as that would have been 10 days without anything running through the drain. And finally, the area with the drain line is the lowest point in the garage. When the garage flooded, it flowed over to that wall.
I'm going to do more looking. Perhaps there is a leak in a fixture somewhere I'm not seeing that, as Harry suggested, is sneaking around under the flooring...
I had a similar problem with a house in Jacksonville, FL. It was a slab floor all the way, and one day I noticed a wet spot in the kitchen where the (then) linoleum floor was bubbling up and separating from the slab.
It turned out that the house was not only built on reclaimed swamp land, but the slab had never been coated with a sealant before the house was built on top of it.
The solution was to take up the floor covering and seal the concrete, then replace the flooring.
Problem solved. Could that be anything like what you are seeing??
Location: Visitation between Wal-Mart & Home Depot
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Total shot in the dark, but... This calls to mind a problem that I had in a rent house in my college days. My roomate noticed a pool of water growing beneath the electric stove so he killed power at the main breaker. When I got home the house was approximately ambient temperature and my roomate had pulled the stove away from the wall and was looking for the source of the leak. To this day I'm convinced he genuinely believed that an electric oven had a water inlet, but that is neither here nor there. The problem was a partial obstruction in the main cleanout that resulted in a back-up. The washing machine drain was part of a recessed fixture, so the overflow was not apparent in the utility room. The back-up water was running behind the baseboards and along the bottom-plate and found an exit into the living space behind the stove.
I'm essentially agreeing with Harry; do you think its plausible that there is a leak from somewhere along the wet wall behind the sink/washer that is traveling beneath the VCT and pooling in a low spot? Will a marble roll from the washer to the puddle?
It's possible that you have a "Hydrostatic Head" under the slab. That is, a small "dome" of water pressure in the earth that gradually pushes moisture through the slab, where it is trapped between the VCT and the slab. The reason that it was not noticeable prior to the VCT installation is that it probably evaporated as it hit the surface of the slab.
It doesn't sound like a lot of pressure, so you may want to remove the tile from the affected area, let it get dry, then perform a moisture test on the slab. Kits are available for that.
While the area is uncovered, I'd go ahead and seal the slab, overlapping the damp area out into the dry slab. Then wait a week during a rainy period and see what occurs. If the dampness does not show up again, then you can replace the VCT.
Location: Sometimes Maryland, sometimes NoVA. Depends on the day of the week
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The more I think about it, the more I think its along the wall, too. We are going to move a few things tonight and look deeper. The good news, its really half-a## finished, in that two walls in the laundry room are just painted block, and all the water lines are exposed. That, and I want to move the freezer, as my gut says there may be condensation on something, what with the humidity of all the rain, no a/c running, and a laundry room. I'm thinking that if we move the freezer, we may find water on top of the VCT. Thats my working theory, as it seems like the best, easiest fix one
BTW, the house is 40 years old. We have owned it for 2+ years. And we have a high water table around here, so the "hydrostatic head" theory intrigues me.
You agree with "leak inside the slab"? But the only pipe in the slab is at least 6 feet away, and its an unpressurized sewer drain. I had it scoped back in Dec and the part in the slab was fine then (should probably consider replacing the 10' line between the house and the septic tank). How could a leak in the sewer line cause water to come up through the slab, rather than percoluating down? Additionally, the spot did not dry out when we were gone for 10 days, which, if it were a sewer line, should have as that would have been 10 days without anything running through the drain. And finally, the area with the drain line is the lowest point in the garage. When the garage flooded, it flowed over to that wall.
I'm going to do more looking. Perhaps there is a leak in a fixture somewhere I'm not seeing that, as Harry suggested, is sneaking around under the flooring...
Good luck figuring it out.
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