Industry Professionals Prefer RH Testing for Concrete Moisture over the CaCl Test. Here’s Why You Should Too!

Calcium chloride (CaCl) tests for moisture in concrete slabs have been shown to be misleading and unreliable when compared to in situ relative humidity (RH) test results. But that’s not just our opinion...

Howard Kanare, a leading expert in concrete moisture issues, says, “With CaCl we’ve got a test which we know has no scientific basis, and in which you can get both false positive and false negative results. In effect, it’s fundamentally unreliable.”

So what moisture test does Kanare recommend? In situ relative humidity (RH) testing. “It’s the only method that’s scientifically proven for accuracy and reliability...and the best predictor of whether or not a floor covering or coating on a concrete slab will succeed or fail.” Learn More



More compelling reasons why thousands of contractors, flooring installers, and moisture testing professionals are switching to RH testing using the Rapid RH® system.

Simplest to Use

The CaCl surface test requires cumbersome prepping, weighing, and recording desiccant. With the Rapid RH® system, simply drill and clean test holes before installing sensors.

Lowest Cost per Test

With the associated time and labor, administering and monitoring a CaCl surface test costs you about 45 times over the Rapid RH® system.

Fastest Test Method in the Industry

Apply the CaCl surface test on a 10,000 square foot slab and you'll spend more than 72 hours administering and monitoring for test results. With the Rapid RH® in situ relative humidity (RH) testing system, you'll have official results in 24 hours. No other test method beats that.

Easiest Compliance with ASTM Standard

With the Rapid RH® system, you are complying fully with ASTM F2170 for RH Testing. Not only that, the CaCl test measures only at the surface of the slab, providing misleading results. The Rapid RH® system measures deep inside the slab for the most accurate moisture readings.

It’s TIME to Celebrate Your 24-Hour Advantage!

The American Society for Testing and Materials (ASTM) has recently reduced the time period to obtain official in situ RH test results by 48 hours. CaCl surface testing (ASTM F1869) requires waiting a full 72 hours before getting test results. With Rapid RH® testing you’ll have scientifically valid results in only 24 hours.

This means the Rapid RH® test gives you the data you need to make important project decisions much sooner. Check out the 24-hour advantage.


The Easy, Convenient, No-Hassle Method

Future Rapid RH® concrete slab relative humidity (RH) sensor readings can be repeated at any time with no extra equilibration time.

With the Rapid RH® testing system, recording your data is also easy and convenient. Simply add the Rapid RH® DataMaster™ app in tandem with the Bluetooth® Smart Reader for wireless tracking. That’s way less hassle versus CaCl surface test reporting.

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