Easy moisture testing strategies for job sites

moisture testingJason Spangler—Wwith today’s technology, moisture testing is no longer grueling work. And yet some professionals still overwork themselves to get accurate moisture readings through unreliable or time-consuming methods. Of course, not all standards need to change. But as the industry becomes more innovative, some standards must be broken to create new ones.

A good example of this is the calcium chloride (CaCl) test for concrete moisture measurement. This test has been used in the industry since the 1940s, but it’s time for a change. For starters, the CaCl test takes 72 hours – 48 hours longer than the standard RH test. It can also be difficult to set up. The concrete slab must be prepared for each test and for the actual application you must bend over or kneel on the floor. It is a very labor intensive process.

“There is no scientific documentation as to why the original test conditions were established,” said Howard Kanare, author and technical director of Koster American Corp. “There are no reasons or published data for shell and dome dimensions, amount of CaCl used, or even why CaCl was used in the first place.”

Surely there is an easier way to perform moisture tests? Relative humidity (RH) testing is steadily gaining popularity as it addresses things that the calcium chloride test is simply not qualified to test for. First and foremost, RH tests are supported by solid evidence. It was specially designed and tested by researchers at Lund University in Sweden. Much of their research is what the ASTM F2170 standard outlines: The RH test provides a quantitative measurement of the moisture conditions in a concrete slab.

That valuable, internal data is something a CaCl test cannot provide, as it only measures the surface conditions of the plate. With the RH test method, you will also get valid results within 24 hours. No more waiting 72 hours. And since there are only a limited number of hours in a day, imagine what it would be like to reclaim time for your construction project.

What is the best test?

Clear and simple, the relative humidity test with in-situ probes is the best choice. The ease of use and accuracy of these types of tests save you time and money. RH testing with in-situ probes involves placing the probes at specific depths in the slab per ASTM F2170 standards. After the RH probes balance, you can take measurements to assess the overall moisture condition of the plate. All you need to do is drill the hole, insert the sensor and collect your measurements. Simple, easy and fast.

There are additional tools and technology that you can connect to in situ probes to help you collect the data. Some companies offer an app that users can download on their smartphone to collect and store readings. Having a central digital storage location for your measurements means your hard work is protected should there be any damage in the future.

In short, don’t gamble away your hard work with an unscientific test. RH testing is the most reliable method as it reveals the true moisture state in concrete slabs – something the CaCl test cannot do.

If you want to take steps to prevent floor disasters, the Rapid RH test system may be the right choice for you.


Jason Spangler, Sales Manager for Wagner Meters, has over 25 years of experience in sales and sales management across a broad spectrum of industries. He has extensive industry involvement with groups such as the NWFA, CFI and FCICA.

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