Perpetually moist concrete slab

[ThatShouldHaveWorked]

We have a plant in Oklahoma City that was built in the 50's. There is a natural spring that runs underneath it. I think the issues we are having is a result of the slab perpetually having moisture in it.

The first issue is we've attempted to have it epoxy painted multiple times both in house and professionally following proper procedures. We have used the same product in multiple plants without issue. However, in this one between a year and year and a half it will start pealing off. We have the same issue when patching with self leveling concrete.

The second is that floor anchors (wedge or epoxy) are hit or miss on how long they'll hold.

I'm hoping someone will have a recommendation for sealing the top surface for painting.

Along with a solution for strengthening floor anchoring. Alternative anchors? Perhaps a chemical to apply to the anchor holes?

Additionally, we are going to be grouting under several machine and tracks. If the issue is moisture in the slab should I be concerned that it may leach into the grout over time and cause problems?

Thank you.

 

[phamENG]

Epoxy coatings can be effective to keep vapor down, but it doesn't do anything if there's bulk water coming up through cracks or water seeping through through the concrete (which sounds like it could be the case).

You need to get rid of the water. Find the source, cut a hole in the floor, and develop a system to move it outside.

 

[ThatShouldHaveWorked]

Epoxy coatings can be effective to keep vapor down, but it doesn't do anything if there's bulk water coming up through cracks or water seeping through through the concrete (which sounds like it could be the case).

You need to get rid of the water. Find the source, cut a hole in the floor, and develop a system to move it outside.

I'll be back there at the beginning of the month. I can't think of a time I saw water coming out of cracks or even holes drill through it. When we cut a short lane to a side door on the building it was darn near a river flowing under the surface. Built a retaining wall out of bags a sacrete it was so wet.

We did have an issue with it flowing into one of the reuse water pits. Got a call that we went from 15-20% less out than in to 25-50% more out than in.

At a quarter of a million gallons a week that adds up fast.

When the city came out to check their meter and it passed I asked them if it worked like solar. "Since it appears we're now making water do you have to pay us for it"

 

[rlmengineer]

You might try lowering the water table by installing a few sump pumps several feet below the floor.

 

[JAE]

phamENG and rimengineer suggest what I would consider.

But you could end up chasing your tail and pouring money into stopping the pouring water.

Might have to remove the slab, excavate down to create a thick layer of drainable material (uniformly graded gravel) with either a thick vapor barrier on top or even a waterproofing system (Volklay panels) and top with a new slab.

Note that with concrete slabs placed over an impermeable membrane you have to be careful to avoid slab curling during the concrete setting.

 

[jhnblgr]

almost all coating will fail if moisture is present above the recommended maximum. The ideal option is to install a barrier under the slab which isn’t likely a viable solution now. You could drill and inject a waterproof slurry but not sure how well that would work. Cutting holes in the slab is an option to lower the ground water elevation but could result in flooding if power goes out. Best solution if possible is to install a manhole and under drain around the area to lower the ground water table and if possible daylight or pump.

 

[ThatShouldHaveWorked]

Thanks for the advice everyone. Seems like there is not a great or easy solution and the risk is greater than the reward.