Background: I have posted 2-3 threads related to cracks in Scandian Bonita wood in "Yikes I have problems" section.
To cut long story short, we started seeing cracks in installed wood after 4-5 weeks of installation. Each party pin-pointed to each other that means consumer -> Installer, Installer -> Manufaturere and Manufacturere to installer. All parties met at our house last week. Again all facts were discussed and 5-6 pin meter tests done at different areas and conclusion is sub-floor moisture is high.

Manufacturer recommended to do Calcium cloride test to measure sub-floor moisture.

Installer is recommending (ASTM 2170). As per him, indepndent inspector will be using (ASTM 2170), drills into the concrete subfloor, probe check will be performed after 73 hours to determine the moisture content of the concrete slab.

Question is : Any method (Calcium Cloride Vs ASTM 2170) better than other? Do we have to stick to Calcium Cloride test if it is recommnded by maufaturer.

A very controversial subject, pros and cons.

But yes, if the manufacturer says CaCl then you should do it. Although some say you can do both.

Personally I like to know whats coming out of the surface and a CaCl tells you that, but not a Rh test. Rh tells you what potentially might come out of the surface but there is no correlation between the two tests. Rh only tells you what the relative humidity is in the concrete. And they all can change if there is no barrier under the slab. So if you did not test prior to the installation there is no way to tell if the slab was beyond specs at that point in time.

Porosity, surface structure (steel troweled) and admixes have a huge bearing on what comes out of a slabs surface.

The inspector should grind the concrete surface 24 hrs prior to setting the CaCl tests. If doing a Rh test he should have documentation that his reusable probes have been re-calibrated in the last month. But if using the Rapid Rh probes re-calibration is not required.

I think your info might be off a bit. An Rh test (reusable) can be read an hour or so after the probe is set as it needs time to equilibrate. But not a Rapid Rh, it can be read in minutes. It's the CaCl test that must be read BEFORE 72 hours. Of course you can read the Rh test anytime after the initial equilibration time, even weeks or months for that matter.

But here's the kicker, a resuable probe reads from the top of the hole to the bottom. In a normal sized slab the depth is an inch and a quarter or so. The Rapid Rh probe only reads at that depth....below the probes bottom. There fore IMHO re-usable probes are deficient in that they read the rh at the top to the bottom of the hole giving you a potentially skewed result. Or an average if you will.

floormeintucson , Thanks for elaborate reply. You have awesome knowledge for both the tests.

Have a nice DAY!!!