I've read all sorts of articles about making sure you do a moisture test, with zero information on what to do if it fails the moisture test. Most articles on the net basically say a moisture test will prevent moisture problems. Uh, hello? How exactly does that work? It all seems to be about installers avoiding liability with a waiver if a floor fails (and most state that). So if my concrete slab were to fail the test (hypothetical, since I haven't yet tested it- I'll be installing a floating floor on concrete slab at grade with moisture barrier underlayment), aside from not putting any floor covering at all on the cement (since all floor coverings will have problems with moisture), what is the point of the test? What can be done if it fails? Why doesn't anyone address that, if the test is so critical?

There's plenty of moisture mitigation systems out there. If the slab fails the test by a slight margin then there are many products out there to use that are topically applied.

Plus there are other things to do like fix grading issues, runoff from the roof ie rain gutters and french drains.

Thank you. That's the first time I've heard that addressed. Most treatments of the subject don't go into that, so I assumed that hardwood was simply a no-go if it failed.

No I did not say that. I'd say 50% of the time my CaCl tests are reading over the 3lb/24/1000sf ceiling which is the norm for the industry. My average is probably around 5lb. Lots of products will work up to 10 lbs without spending a fortune on mitigation. Then there are epoxy types that work well beyound that.

You need to find someone that is experienced at performing the tests and reading them correctly, plus be knowledgeable at application of the moisture retarders.

I am a big fan of the Franklin Products. If you have access to them I would recommend their 531 moisture barrier, paired with the 811 advantage. If you do not use their adhesive with the MB you will void the warranty. The 531 Moisture controll system has a ten year warranty on any moisture through the slab with NO moisture test necessary. It must be rolled on with a 1/2 inch nap. You have to read the directions carefully to ensure that you apply it to the correct thickness. You must also spend a great deal of time prepping the slab. I fully scrape the floor, then use a black pad, and an open coat disc. Subfloor has to be very clean. Once applied you have a very smooth subfloor to glue your new floor to. Fantastic product.

I have to second GHFS Adam. Franklin makes some awesome products and since I last checked the best warranty. They will even pay for labor and materials. But you better have your ducks in order.