Key Questions to Ask Flooring Contractors About Moisture Testing

Getting flooring installed is a big project that takes significant time and expertise—which is why many people hire flooring contractors to complete the project. This can take away a lot of stress, since licensed professionals should know the ins and outs of the job.

It’s usually not too difficult to find a contractor. Finding a good one, however, can be another story.

So when it comes to flooring installations, what can help you determine the difference between the good contractors and the so-so? The seasoned pros and the rookies?

Accurate moisture testing is one part of the project that can make or break a flooring installation. It’s essential in helping you avoid costly flooring failures from damage like cupping, buckling, or gapping.

So, any flooring contractor who skips moisture testing, rushes through it, or tests improperly can end up costing you thousands of dollars and a lot of wasted time.

So what questions should you ask a flooring contractor before hiring them? How can you tell if they rely on tried-and-true methods for testing and managing moisture before, during, and after an installation?

Let’s take a closer look at the relationship between moisture and flooring installations, and then determine what you need to know from flooring contractors before deciding to work with them.

Why moisture testing is critical in flooring projects

Excess moisture in subfloors or flooring—whether concrete, wood, or another engineered material—can lead to costly flooring failures.

Buckling occurs when wood picks up extra moisture (from the air or from the subfloor) and the wood swells, which creates little hills, or humps, in the flooring.¹

Cupping happens when the bottom of a floorboard absorbs moisture from the top of the subfloor due to a moisture imbalance. This causes the edges of the floor boards to swell higher than the center, creating a “cupped” shape.²

And since wood expands and contracts due to changes in relative humidity, if floorboards are installed with a higher moisture content than the surrounding environment, they will evaporate the excess moisture and shrink, forming gaps between the boards.³

The possibility of these types of moisture damage, among other causes of flooring failures, is why moisture testing is critical in flooring projects.

Additionally, different flooring materials have different moisture sensitivity levels. For example, while different types of tile (e.g. porcelain and ceramic) and vinyl have low moisture sensitivity (or are highly resistant to moisture) while engineered wood and laminate are moderately moisture-sensitive. And hardwood flooring can be highly sensitive to changes in humidity.

No matter the moisture resistance level of flooring, none of them are completely waterproof.

That’s why it’s so important to hire a flooring professional who understands different types of flooring, how they behave in different areas of the home, and how the humidity in an environment fluctuates over time. Each situation can require a different method of moisture testing, and you want to make sure your contractor understands these details.

Key questions to ask a flooring contractor about moisture testing

There are a number of questions you can ask flooring professionals to make sure they’re the right contractor for the job ahead. Here are a few to get you started.

1. What moisture testing methods do you use?

There are several moisture testing methods that can be used based on the type of flooring, the type of subfloor underneath, and the environment the flooring will be installed in.

This means there are also different moisture meters that can be used for this testing: pin or pinless. There are pros and cons to both, and the flooring professional should know which type of meter works best for your flooring project.

Pinless meters use electromagnetic waves to detect moisture in the material. Higher-end pinless meters, like Wagner’s Orion 950, have a dual-depth setting, so they can measure at ¼” or ¾” of the material’s surface.

Because pinless meters don’t puncture the flooring material, they are fast, which means you can get more readings, in more places, across a wider area—giving you a more complete picture.⁴ They can provide surface readings and in-depth readings of up to ¾” of the flooring material.

However, pinless moisture meters can have difficulty testing material that isn’t completely flat.

Pin meters typically come with different pin lengths, so you can measure moisture at various depths. They measure moisture content between two pins that are inserted into the material, so more readings at various areas of the flooring material are necessary to get a fuller picture of the overall moisture content.

However, since pin meters use two prongs, they poke holes in the flooring material. Also, it can be difficult to get the pins to puncture harder flooring types, and this can cause broken or damaged pins in the meter.⁵

There’s also relative humidity (RH) testing, which is best for testing concrete when flooring is installed over a concrete subfloor. For this test, contractors drill a hole in the concrete and insert in-situ probes or sensors to measure the moisture content deep within the slab.⁶ Products like the Rapid RH L6 make this an easy process.

2. Do you test for moisture in both the subfloor and flooring material?

Testing the subfloor—which is often concrete or wood—and top flooring material is crucial because any moisture from the subfloor could get trapped between it and the flooring on top, whether it’s a new or existing floor covering. This can cause buckling, warping, mold, or any other number of moisture-related flooring issues.

When installing wood flooring, a good contractor should also know the equilibrium moisture content (EMC) for the type of wood being used (or “the moisture level where the wood neither gains nor loses moisture since it is at equilibrium with the relative humidity and temperature of the surrounding environment”).⁷

Since wood either shrinks or expands as it takes in and releases moisture from the environment it’s in, the contractor must make sure the flooring material is at the proper EMC before installation so that it won’t expand or shrink after it’s been installed.

In short, moisture testing the subfloor and the flooring material ensures that the flooring project will last a long time, so make sure your contractor tests both!

3. How do you determine if the flooring has properly acclimated?

It’s important to let wood acclimate to the environment it’ll live in, making sure it has time to reach the proper EMC before installation.

The timeframe for acclimation varies based on the flooring material and the humidity level of the environment.

Your contractor should understand the acclimation process for whatever kind of flooring material you want installed. After the appropriate time, the contractor should then use a moisture meter to test the moisture content of the flooring material to verify that it’s ready for installation.

4. What moisture content levels do you consider safe?

As mentioned before, ideal moisture content levels vary by flooring type. But if moisture content levels are too high in the flooring material, it can cause cupping, buckling, crowning, or even mold growth. If the levels are too low, the flooring might crack or split.

Gauging the optimal EMC in flooring materials before installation significantly reduces the risk of running into moisture-related flooring issues later on.

5. Do you use a moisture meter? If so, what type?

There are various moisture meters on the market, some better than others. The difference between professional-grade and cheap-grade all comes down to having consistently accurate moisture readings.

Professional-grade moisture meters will be highly accurate and include a way to check the calibration of the device. If a meter’s calibration is off, the readings will be inaccurate, which can ruin a flooring project from the start because flooring installation decisions are based on those readings.⁸

So even though a professional-grade moisture meter will certainly cost more money on the front end, they save thousands of dollars on the back end. A flooring project with no mistakes to correct is the goal, and a professional-grade meter will get your contractor there.

Whether the contractor has a cheap-grade or professional-grade meter (or whether it’s pinless or pin-style), they should take multiple readings of the flooring material to get as accurate a reading as possible. If you notice the contractor only takes one reading, you might want to question whether or not they know how to use a moisture meter correctly.

They should also verify the calibration of the device (if possible), and even make sure the device is set to the correct material they’re measuring. All of these will be signs that your contractor is knowledgeable about how to use a moisture meter properly.

6. Do you provide documentation of moisture readings?

Flooring professionals should always document moisture test results so that they can keep track of when flooring material is ready to be installed.

A proper moisture report includes several elements: date, location, temperature, humidity, testing method, and the moisture content reading. If any of these elements is missing, it can compromise the flooring project and make potential future problems difficult to dispute. When all of the necessary information is consistently present, then there is an accurate log, or narrative, to look back on to see where something may have gone wrong or to rule out possible issues along the way.

Wagner Meters includes a series of apps—for concrete, wood, and ambient conditions—that make keeping track of information quite simple. Available for both Android and Apple devices, these apps can log data automatically, generate reports, and have Bluetooth connectivity.

Red flags: When to be concerned about a contractor’s moisture testing practices

Asking the right questions can help you hire the best contractor for your flooring project, but asking questions isn’t a guarantee that the contractor won’t make mistakes. If, for example, you notice the contractor doesn’t mention moisture testing at all, or if they don’t use a moisture meter but instead use touch and visual inspections to detect flooring moisture issues, that is a cause for concern.

Not documenting moisture readings, not generating reports, or dismissing humidity and environmental conditions as factors in flooring failures…those are also causes for concern.

To put it more simply, observing and communicating with a flooring professional before, during, and even after a flooring project is key to a successful installation.

Asking the right questions leads to flooring success

Asking a flooring professional these key moisture testing questions can prevent flooring failures that will cost you time and money. Working with contractors who prioritize moisture testing, use professional-grade moisture meters and keep track of accurate data will lead to a successful flooring installation project.

And if you’re looking for professional moisture testing tools, look no further than Wagner Meters’ industry-leading moisture meters!

Last updated on April 6th, 2026