Hey there. We had hardwoods installed in the entire downstairs of our condo. The wood is buckling in the downstairs bathroom, and the epicenter of the moisture appears to be in front of the toilet. We have ruled out all plumbing problems or even a roof leak. I've had a multitude of professionals look at it. No one can give me a straight answer, but the general consensus seems to be that moisture is coming up from the slab in that spot. The house is very close to the lake (15 feet away). The floors were put down as follows: plastic, 3/4" subfloor, felt paper, then 3/4" oak tongue & groove nail down floor. They did NOT use a chemical waterproofer on the concrete. I have a floor installation guy that says a chemical waterproofer will DEFINITELY prevent this from happening again. But he says the ENTIRE downstairs must be covered so the water doesn't migrate somewhere else where we haven't put the sealer and cause buckling there instead. This obviously means ripping out ALL the flooring and subflooring and starting over. I would appreciate all expert opinions on this! Thanks!