The Proper Number of Tests for Concrete And Why It’s Vitally Important

RH testing using ASTM F2170 guidelines has been scientifically proven to be the most reliable method for measuring the moisture condition of concrete slabs.

Skimping on moisture testing is dangerous for your customers and your reputation.

It’s not worth the risk.

Instead, follow these guidelines for proper concrete moisture testing using the ASTM F2170 standard.

What Is ASTM F2170, and Why Is It Important?

ASTM F2170 provides the standard for relative humidity (RH) testing in concrete using in situ probes. For measuring the moisture condition of concrete slabs, this method has been scientifically proven to be the most accurate test.

So by following the ASTM F2170 guidelines, you are giving yourself the best shot at success.

How Many RH Sensors Do I Need?

ASTM F2170 requires you to use 3 concrete moisture sensors for the first 1,000 square feet of flooring. Then, for each additional 1,000 square feet, you’ll need to place another sensor.

So if you have 5,000 square feet to test, you’d need 7 RH sensors or in situ probes.

Why So Many RH Sensors?

A 1,000-square-foot slab poured at a 4-inch depth equates to about one truckload of wet concrete.

Typically, a 1,000 square-foot concrete slab poured at a 4” depth equates to about one truckload of wet concrete.

When you test with the proper number of sensors, at least each truckload will likely be tested with 1 sensor or more. And since the water-to-cement ratio can vary between loads way more than you might think, it’s important to test each one.

Using 3 sensors in the first 1,000 square feet increases the odds of accurately assessing the slab’s moisture condition. Sometimes, a sensor can be installed into a piece of aggregate, resulting in an unusual reading. That’s why it’s safer to use 3 sensors for the first 1,000 square feet.

Wondering the Best Way to Apply All This New Knowledge?

Now that you know why the 1,000-square-foot requirement is important and how many tests you need to use, the next step is to find the right testing system.

The best relative humidity testing kit on the market is the Rapid RH L6 system from Wagner Meters. It’s easy to use, and its accuracy is unbeatable. This technology, paired with a smartphone app, makes data testing and storage a breeze.

For your future jobs, be sure to use Wagner’s checklist for easy RH testing.

Jason Spangler

Jason has 20+ years’ experience in sales and sales management in a spectrum of industries and has successfully launched a variety of products to the market, including the original Rapid RH® concrete moisture tests. He currently works with Wagner Meters as our Rapid RH® product sales manager.