Relative Humidity Testing: What It Is And Why It’s Your Best Concrete Moisture Testing Option

High concrete moisture levels can cause floor coverings to bubble and wood to cup.

The concrete moisture testing method you choose can mean the difference between a successful project and a failed floor covering.

This is because some concrete moisture test methods provide more accuracy, information, and credibility than others.

If you want to avoid any warping, cupping, or staining that could seriously damage your client’s floors, skip the uncertainty of insufficient testing methods and use the method proven to get the most accurate results—relative humidity testing.

In this article, we’ll explore:

• How relative humidity (RH) testing works
• The benefits of choosing RH testing
• How to choose the right RH testing system

Let’s start with a closer look at the RH testing process.

How Does Relative Humidity Testing Work?

Relative humidity testing uses in-situ probes to test the relative humidity within a concrete slab.

This is done by drilling a small hole into the concrete—40% deep if your concrete is drying from one side and 20% deep if your concrete is drying from two sides—once the room containing the concrete has reached service conditions.

From there, the in-situ probe sensor goes into the drilled hole. If you’re using the L6 Smart Sensor, it will usually give a reading one hour after installation that is within 3-5% RH of the reading you would see after the ASTM-required 24-hour mark.

Official readings, however, require you to wait 24 hours. But this early estimate will give you a sneak peek of what moisture level you can expect so you can start thinking about your next step—whether that’s making a business decision or speaking with a customer—sooner.

That’s it. Pretty simple, right?

But what is it that makes RH testing more effective than other concrete moisture testing methods?

What Are the Benefits of Choosing RH Testing?

RH testing measures deep, complies with industry standards, and helps you prevent flooring failure and save time and money.

Let’s take a look.

1. It measures deeper

Calcium Chloride testing is an ASTM compliant surface-level concrete moisture test.

One of the greatest benefits of RH testing is that it measures deeper than other acceptable concrete moisture tests. These deep measurements give a more comprehensive picture of how much moisture a slab of concrete contains.

Most moisture concrete tests—calcium chloride and concrete moisture meter testing—only measure the surface of a slab of concrete.

That’s not to say these surface tests don’t offer valuable information. They can still detect the presence of moisture. Concrete moisture meters are especially handy for finding moisture hotspots or surface conditions in that moment.

But RH testing is the best way to get a quantitative idea of how much moisture the slab contains, and your risk profile for long-term flooring failures.

RH sensors are placed into holes deep within a concrete slab. Since most concrete moisture is deep within the slab, deeper tests mean more accurate moisture readings.

Readings from surface-level tests are often just the tip of the iceberg. You might think you understand the problem, when in reality, the problem may be even bigger below the surface.

2. It complies with industry standards

RH testing is ASTM F2170 compliant. The fact that ASTM standards recognize this testing method further cements its credibility.

Besides that, RH testing isn’t limited to surface testing like calcium chloride tests or concrete moisture meters. It is also unaffected by factors that throw off concrete moisture meter readings like rebar, various mixes, and different types of aggregates.

3. It can help prevent flooring failure

The Total Reader sends the results of the Rapid RH L6 Probe to the DataMaster App where you can view moisture reading reports.

Some RH testing products can help you predict flooring issues by using apps and product add-ons.

Wagner Meter’s RH testing probes, the Rapid RH® L6 sensors, connect to the Total Reader® or DataGrabber® with Bluetooth® so you can view the moisture trends of the concrete slab using an app.

You can even program the optional DataGrabber™ to gather moisture readings at specific time intervals, allowing you to take readings as often as you want.

Having this record can help you see how your concrete’s moisture levels are changing so you know when it’s dry enough to safely install a floor covering on top.

4. It saves you time and money

When you make a purchase for your business, you don’t want to waste your money. You want something you know is worth it, something you’ll be able to trust and depend on, something that will make your life easier instead of harder.

So it’s not really saving money to buy cheaper but insufficient or confusing moisture tests that, in the end, can’t give you the level of information you need.

RH testing goes well beyond surface-level testing to provide comprehensive data about a slab’s RH levels, all while making the process straightforward and user-friendly.

RH testing can also save time and money in other ways.

Some RH products, like the Rapid RH L6 sensor, can be paired with other devices and apps to automate the moisture monitoring process. Not only can this save you and your team the time and money of taking trips back and forth to the jobsite, it can also help you predict high moisture levels so you can prevent flooring damage.

This way, you can save time and money by not having to repair damaged floors and a damaged reputation.

Choose the Right RH Tools for You

At Wagner Meters, we offer a variety of RH testing systems to suit your concrete moisture testing needs.

Our three main systems are:

• Hands-On Monitoring: If you don’t want to bother with the extra bells and whistles, this is one of the simplest forms of moisture testing. All you have to do is read the L6 sensor with the Total Reader. If you wish, you can also use the DataMaster app to get RH and ambient readings.
• Automatic On-Site Monitoring: This testing system ensures you can view moisture readings over time. Our DataGrabber with Bluetooth attached to our Rapid RH L6 sensor will take subfloor moisture readings while you’re away. When you come back to the jobsite, you can use our DataMaster app to gather all the readings the DataGrabber collected.
• True Remote Monitoring™: Skip all the unnecessary trips to check the RH probes at the jobsite in favor of getting live readings sent to your phone. You don’t even have to be in Bluetooth range to get the results. Floorcloud™ technology allows you to access your concrete’s moisture readings from anywhere in the world (as long as you have an internet connection).

Want to know more about what it’s like to use RapidRH?

See what other customers have to say about them on our customer testimonials page.

Or head over to our store to view the full collection of RH products for yourself.

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.