Mitigate effects of seepage in finished basement


Old 06-30-17, 10:16 AM
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Mitigate effects of seepage in finished basement

I have a finished den in my basement. This morning I heard a dripping sound and cut out some sheetrock. The sound I heard was water dripping off the end of an abandoned piece of wire which was running down the block foundation wall. I can see far enough down the cavity between the block and the studs to see a number of glistening beads of water running down the block wall. This appears to be just seeping water from outside (it is raining steadily today).

The basement was finished like this:

The concrete slab was not level, so treated 2x4's were ripped down as necessary and fastened to the floor with ramset nails. Then heavy black plastic on top of these "joists" followed by 3/4" plywood subfloor, then carpet.

2x4 stud walls were built (treated wood) about 2" or so away from the block foundation wall. The blocks have been painted at some point (not sure if regular paint or drylock). No vapor barrier or insulation in these walls. MMR greenboard drywall was used for the walls.

There is what appears to be an old perimeter drain system at the bottom of the block walls. Basically a stiff piece of plastic that runs into the concrete where the slab meets the block. At one point there was a tarp-like material that ran from behind that plastic up the block walls, but most of it was cut out at some point in the past. I don't know where this plastic drain thing is channeling water (around the perimeter to some kind of exit point? or just back out the bottom of the wall?) but from what I can see the slab itself seems pretty dry except for where I heard the dripping.

It does smell quite musty or possibly mildew-y in the cavity between foundation wall and stud wall. I don't see any signs of mold but visibility is somewhat limited and the drywall is less than a year old.

I'm not yet at a point where I am willing to take down the entire finished wall to address the water seepage. Nor am I willing to dig up the back yard to address it from that side. I have 2' overhangs and gutters and the ground is graded away from the house. I believe it is simply a 60 year old leaky basement wall and I can see it being very difficult if not impossible to stop water intrusion altogether.

I'm not sure how concerned I should be about this. Aside from the water dripping off of the wire outside of the plastic channel (which I fixed this morning), most of the water that I can see seems to be going into the drain thing. I don't know if it is just sitting in there or exiting somewhere.

I ordered a humidity meter and will likely get a dehumidifier. However I am more concerned with dehumidifying the cavity behind the finished walls than I am the finished den itself (it doesn't seem overly damp or musty).

I wonder if I were to cut several holes in the drywall and covered them with hvac grilles if that would allow a 70pt. dehumidifier to pull in the damp air and treat it?? Or, would it just allow the mustiness to enter the finished room?

Another idea is to put a very small dehumidifier in the wall cavity behind an access panel. I suppose then I would have to open the panel and check the water then empty it manually periodically as these smaller units don't seem to have ability to hook up to a drain hose.

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Old 06-30-17, 10:22 AM
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Dealing with water once it's inside your basement is like bailing a boat but not fixing the leak. As always the best place to deal with a water problem is outside. First make sure any perimeter drain is not clogged and can freely drain to daylight. Also make sure all the ground around your house slopes away for 6-10 feet. Make sure the gutters and downspouts are installed, intact, clean and drain well away from the house. Basically do everything you can to keep water away from your house on the outside.
Old 06-30-17, 11:03 AM
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I have done that as much as is reasonably possible. Big overhangs. Big gutters.
Grading. But ultimately this is an old porous block wall. We have a high water table and when the ground gets saturated I believe pressure is just going to force moisture through the wall. Short of MAJOR work that I am not prepared to do, I just don't see a way to prevent 100% of the water from getting in. I'm not talking about buckets and buckets of water, but it is more than a few drops.
Old 06-30-17, 11:44 AM
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Sounds like you have a bad situation and it is actually worse than what you see. You are looking at the liquid form of moisture but the vapor form is just as damaging, perhaps more so because things can look dry yet once enclosed the moisture accumulates and that 4 letter word starts to grow. Buyers and insurance companies will run when you say that word.

The stiff piece of plastic you describe sounds like an attempt to catch the water and drain it away, but as you said, it has not been maintained and unknown where it drains to. I suspect the solution, if there is one, will be to start over but that will certainly be a budget buster. If the mold gets started and that is what you are smelling, those walls and the floor may need to be removed to save the house and your health.

The previous owner did a good job at hiding a major problem and he should pay, but that is impossible.

It is still a basement and it may have to return to being a totally unfinished one.

Old 06-30-17, 01:26 PM
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I believe it is simply a 60 year old leaky basement wall and I can see it being very difficult if not impossible to stop water intrusion altogether.
You are probably right and all the more reason to open the wall now.
I'm actually more concerned about what's trapped under the black poly on the floor.
Old 07-25-17, 06:36 PM
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Is there a sump pump in the basement, was the basement ever waterproofed?

Is there a plastic covering all along the basement perimeter wall? That would indicate weep holes were drilled and drainage to a french drain along the footing, under the concrete floor. The stiff plastic keeps dirt out and directs the moisture down to the french drain pipe.

Is there a sump pump pit, is it dry?

The fact that water is dripping means: there's a hole in the wall or the wall is not draining thru the weep hole (fast enough?); or there's a stream flowing directly to your house.

When my basement was water-proofed, they provided a clean-out opposite from the sump pump pit. I can test the piping by dumping water in the clean-out and watching if it drains to the sump pump pit (from both directions).

I can send a picture of what a plastic covered leaking concrete block basement wall's not pretty (when exposed).
Old 07-26-17, 06:48 AM
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I'm sorry but this sounds like a basement which never should have been finished. I think the walls (at least the sheetrock) need to come down or you need to bite the bullet and do the work outside to get the water away from the wall.
Old 07-26-17, 09:56 AM
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I'm not sure how concerned I should be about this. Aside from the water dripping
A lot, nothing good will come from just a few drops of water (at least what you have found so far) that will not turn into a much bigger problem.

You need to find where/how the water is getting in vs trying to convince yourself that there is a way to manage what you know is only going south.

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