Atelier is right on the money as far as moisture testing is concerned and it is best to slab test on or right after high humidity and rainy days to get the worst-case-scenario test returns. The flooring system integrity will only be as good as it is in its worst day in the enviroment its installed in. After you get test results and compare them to the manufacturers product tolerances, then you can decide on the right product for that application or other remedies to bring it to withing manufacturer tolerances. The key here is prevention. Guessing isnt knowing, and any preventative measures used by guessing might be overkill OR might not be enough for the product. You just dont know without testing and in some cases an area will never be good enough for some products without rectifying the underlying construction causing the problem. Yes, some adhesives and substrate treatments will add a water vapor barrier and stop or stem hydrostatic pressure in the substrate but they all have cap limits. Owens Wood Flooring has a comptehensive information section of their site on Owens Plankfloor Gluedown Installation Owens states the following: "MAKE CERTAIN BUILDING INTERIOR AND SUBFLOOR ARE DRY Interior walls should be dry enough to be painted and a room temperature as required by adhesive manufacturer with a relative humidity of 30-50% should be provided before any installation begins. To determine if a concrete slab is suitable for hardwood flooring, please follow the NWFA guidelines to perform a Calcium Chloride test. If excessive moisture is present, do not lay flooring. Check floor in several locations. Concrete sub floors must be clean, flat and sound and of sufficient compression strength (3000lbs PSI) being sure that the surface is not slick. Sections not flat such as waviness, trowel marks, etc. are to be eliminated by grinding or the use of an acceptable leveling compound. Especially along the walls, the sub floor flatness must be checked and, if necessary, improved. Flat to 1/8" in an 8 radius. In addition to concrete sub floors, these products can be installed over dry, flat wood sub floors, such as plywood. If plywood is used as an overlay over an existing sub floor, the thickness of the overlay material much be such as to yield a total ¾" sub floor thickness. New wood type sub floors should also be checked for moisture using a moisture meter. In general, wood or plywood sub floors should not exceed 12% moisture content or 4% moisture content difference between wood flooring and sub floor." The NWFA is a resource you can only get information from if you are a paying member, so you might want to search around for the same information on calcium chloride tests from a independent source if you or your installer isnt a member. It should be noted that there are different types of moisture testing. 1. Relative Humidity of the Installation Area. 2. Moisture in the substrate itself hydrostatic Pressure. 3. Moisture testing the wood looring itself before the install to ensure its equalized to the within-tolerance installation area humidity. Here is some more information you may find useful: moisture testing hardwood flooring moisture testing for relative humidity in a room hydrostatic pressure in concrete ASTM F2170 ASTM F1869 your installer should be well educated in all of the above. ask them plenty of questions and get a good comfort level in their abilities. ask for and check out their references too.

Could the weeping be condensation and not a wet floor. If the floor was wet, wouldn't the carpet you pulled up be kind of moldy and damp? Have you tried the moisture test? You take a piece of polypropylene plastic and tape in down with tape so it is well sealed. You leave it for at least 24-48 hours. You can google "moisture teat on concrete slab" for further details.

To the worthy's "inevitable" point, unless the slab is done REALLY well, you're going to end up with water under the concrete somewhere, and concrete wicks. I've yet to see a "normally produced" home that has the poly under the slab done completely right (i.e. all seams taped, penetrations from pipes sealed, use of non-sharp gravel to avoid small punctures). Once that small amount of moisture is in your slab, You can deal with that small amount a few ways. 1) use a subfloor system that permits the moisture through but attempts to provide a drying or draining mechanism and keeps it away from the finished floor for it. 2) Cover the concrete in something with a very low vapor permeability that won't rot or degrade and make an insulating vapor barrier (i.e. XPS foam board) under your flooring. Your "tote" is a perfect example of this. All the water under that container was kept there until you lifted it. Imagine one large unbroken tote from wall to wall. Unless you have running water, this will keep the ambient moisture in the slab right where it is if done well. 3) Use a flooring product that is semi permeable, like stone or tile, and simply condition / dehumidify the space and be mindful of what is left sitting on the floor. If you try to use a masonry flooring that blocks the water, it may loose its bond over time from vapor pressure. Here's a good BSC article explaining the basics: https://buildingscience.com/documents/digests/bsd-103-understanding-basements

We had beautiful wood-grain style tile in our master bath and liked it well enough until I saw the newer luxury vinyl planks. I had to be convinced to even consider them for our new house, but after reading posts on this site and going to a reputable flooring distributor, I am convinced that this is the best alternative to hardwood. Softer and warmer and yet your house could be underwater for months and the floors would still be intact. You have to decide between SPC and WPC (I'm going with WPC) and glue down (quieter - even though we have large rugs) or floating installation, but I was stunned by the beautiful options.