Damp basement floor

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rogar6

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I'm in the process of building a theater in my basement but after performing the taped plastic to the floor test and seeing moisture develop, Im down to essentially one solution.

I have a sidewalk about 4 feet from my house that is tilting towards the property and causing water to collect near the house. I'd like to mudjack to get it level and install a french drain however I live in a townhouse and dealing with the association is a hassle.

My last option is to install a radon fan to see if it will dry out the slab. I recently drilled a few holes in the slab to see what was going on. One area ( a dry spot in the concrete) I dug up had a moisture barrier under the slab but in one of the "dark" concrete areas I dug up there was no moisture barrier.

Any suggestions?

basement.jpg
 

Sparky617

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Do you have a sump pump in the basement? Is it completely underground or a walk out on one side of your townhouse (front or back) Are you an end unit?

What flooring are you looking to use?
 

rogar6

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Yes I have a sump pump that is underground. I would like to lay down carpet tiles although I even considered a concrete stain with epoxy but even an epoxy would eventually be worn away with the moisture in the slab.
 

nealtw

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Sump pump for drainage or sewer?

The water table is to high under the house, so if there is a perimeter drain, it is not doing the job.
 

rogar6

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It's for drainage. Would you recommend scoping the drain tiles (pipes)? The strange thing is the damp spots are about 20' or so from the outside wall.
 

nealtw

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Yes I would and if nothing else works, think about trenching a few lines to pick up the water under the floor. And what about sewer leaks, under the floor, plumbing?
 

Sparky617

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  • Does the sump pump run periodically?
    Are there any sewer lines close to the damp areas?
    Where do your downspouts dump out?
    Are they piped away from the house or do they drain on to the sidewalk that slopes towards your house?
    Is the HOA responsible for all exterior maintenance on your townhouse?
 

rogar6

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neal, what do you mean by "trenching a few lines to pick up the water under the floor?"
There are no drains or water lines under the floor.

Sparky, Yes, the pump only runs when it rains. The downspouts drain far enough away that they're not the problem, I think it's mostly the sloped sidewalk along with a hill in the middle of my front yard that also directs some water towards the house.
About the HOA, they're responsible for certain aspects of outside maintenance but I need to see if drainage is included.
 

nealtw

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Trenching: cut lines in the floor and dig ditches and install perferated pipe and gravel so water can be pumped out.
Exterior perimiter drain should be looked after for you as that is outside maintenance but short of that, finding a way to remove the water is what you have to do.

If the perimter darins are not carrying water away from the building, the pressure will build up against the foundation and sooner or later it will find a way in.
 

rogar6

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Just wanted to update this thread. I sent an email to my homeowners assoc about my drainage issues and am waiting for a response. Will post again with any new info. Thanks for all the helpful advice.
 

stadry

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there are also epoxies which will be applicable + stop water vapor from rising to the floor's surface,,, we often use them for that purpose prior to installing acid stain/epoxy/polyaspartic/cementitious overlays
 

rogar6

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What happens when the moisture meets the epoxy? It seems like the pressure of the moisture will build up and if it does, what would happen?
 

stadry

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damned if i know but the places in which we used it are still in fine shape - some jobs are 12yrs old
 

rogar6

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Stadry, you've used an epoxy coating on basement slabs that would fail the taped plastic sheet test? If so, was there anything special about the epoxy?
 

stadry

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its a standard for epoxy coatings & decorative conc overlays,,, i don't recall the 'rising damp' spec just now but most mtls will have that # on the product sheet,,, 'special' = formulated for the purpose
 

rogar6

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ok. I'll research some epoxies out there and see which will do the best job, thanks.
 

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