How To Read A Moisture Meter Correctly

how to read a moisture meter

A moisture meter is an essential tool for the detection of moisture content in materials in many industries. Also, home and building inspectors use moisture meters to identify potential problems and damage to moisture building structures. Woodworkers, like furniture manufacturers, use wood moisture meters to ensure a product of quality. Contractors are using moisture meters when they install a floor over a concrete slab or floor, to determine the ideal conditions. With this, you must know how to how to read a moisture meter.

Moisture Meter Content

Whoever works on wood, whether they are woodworking specialists, wood floor installers, furniture manufacturers, cabinet manufacturers, building materials sellers, or manufacturers of musical instruments, to name a few, must know their moisture content. The moisture content of wood is defined as the weight ratio of water in the wood part to the weight of the wood without water.

You can not know if a piece of wood is right for your project without knowing its moisture content. The required wood moisture content usually reaches 6-12 percent, depending on the type of project and where you live. Some research may be necessary to determine the correct moisture content for your geographical location and your specific wood project.

Why is the quality of moisture outstanding?

The moisture content of wood is relevant because the moisture content of wood is reduced or increased. In other words, it changes its physical size. This can cause several problems. Imagine building a beautiful wooden cabinet for hundreds of hours only to see it start to deform later. These problems can be avoided easily if you know the moisture content of the wood.

Wood Shrinking and Expanding

While the amount of diminution or expansion varies between species, wood generally shrinks or expands around 1% across the grain, with moisture content changing by 4%. However, even with significant changes in humidity, wood shrinks or extends throughout the grain.

You will need a range of equipment to do a detailed and systematic job as a water damage specialist. One of the most important is a reliable moisture meter.

What Is A Moisture Meter Scale?

Most humidity meters may be used in a mode offering measurements taken on a scale with two endpoints. Different ranges will indicate whether the space is wet or dry.

For instance, one moisture meter can run from 0 to 200. A particular low range in that scale can show that a space is too dry and that moisture measures are far below acceptable. The focal range on this scale indicates that a room is in good shape. And the high end of the scale means that a region has too much humidity and requires remediation.

Why use the moisture meter scale of this type? Because in more than one type of material, it enables you to use a moisture meter. In other words, it allows a moisture meter to be much more flexible and versatile than otherwise.

When tested with a moisture meter, different materials have physical properties that make them react differently. For example, wood is electrically resistant to drywall — this affects how a moisture meter measures the moisture content of each material.

A moisture meter is, therefore, typically designed to deliver accurate, measurable results in specific content. The type of material for which the humidity meter is calibrated is usually referred to as the reading scale of the meter. A wood-calibration humidity meter is said to have a wood-moisture reading scale, while a drywall-calibrated meter has a drywall reading scale.

However, the reading scale for a specific material is not optimized for all humidity meters. These humidity meters have a so-called “reference” reading scale for humidity. These measurements provide a qualitative or estimated evaluation of a material’s moisture content.

Additional Information

Why would someone like to use a reference read moisture scale rather than a more specific (and accurate) scale? Part of the explanation is that certain products don’t have moisture read scales. For instance, concrete does not have a true, quantitative reading moisture scale. It is because the mix used for the production of concrete may vary too much from batch to batch. This leads to inconsistencies that make a direct assessment of the moisture content of concrete almost impossible.

Another explanation might be that moisture tests on the reference scale may provide a fast pass / fail moisture content assessment.

Flaws and How To Read A Moisture Meter

While pinless humidity meters are not as susceptible to inaccuracy from material temperature changes, defects in a material can affect them. Why would the material defects be tested? Since the electromagnetic frequencies used to inspect the material in question use radio wave distortions to determine the humidity content of construction materials.

Material defects such as wooden whorls or air pockets in poured floorings affect the specific gravity of the material (SG). Since pinless meters are calibrated as standard by using specific gravity, random SG changes for materials can impact the accuracy of their moisture readings.

How Do I Read A Moisture Meter?

Here’s how you can interpret and read moisture meter correctly.

Start by taking an unimpacted area measurement. 

You can use this as a base for other measures when capturing the amount of moisture in a non-affected area. For example, if you take a hardwood floor measurement in a non-affected area of 25 on a scale of 0 to 100, you can use that as your baseline. A 25 read does not mean that a substance has a moisture content of 25 percent (MC); it simply means that the substance has relatively low humidity.

If you take a 0-100 scale test in the affected area 63, you will know that the area is much too humid.

As you start your work on the floors in the space concerned, you can set your ultimate goal at level 25. When you dry the space, you can use the moisture meter to track your progress. You can check whether your drying of the affected materials is really progressing.

Some moisture meters have features that help you monitor your progress. 

Many readers of moisture have an analog pin that goes up and down with moisture. When the pin goes up and down, it is set in one of the three color-coded areas of the dial. If it settles in a green range, you know that there is an acceptable amount of humidity. If it settles in a yellow band, you have to look more closely. When it ends in a red range, you know that the area is far from dry.

Ensure that you take both wet and dry measurements every day. Weather conditions can change temperatures and relative humidity in size. You may also note that comparable metrics such as these are not as precise as other tests. But, they can be useful for measuring your progress.

Pro Tips To Read A Moisture Meter Right

If a reference scale humidity meter is used, reading humidity from a sample of material that you know is dry until further testing can be helpful. This gives you a point of comparison for potential references — which helps you to classify products with moisture more accurately.

Also, it is important to remember that the number provided does not precisely measure the moisture content of the material being tested when using a reference scale meter. Arbitrary number ranges like 0-255, 0-300, or 0-100 can be available in reference scales. However, the number you provided is not an absolute, percentage-based indicator of humidity content, even for a reference measurement of a range of 0-100.

How Moisture Meter Affects Accuracy

Damage to a moisture meter can have a significant effect on the precision of the meter. For instance, a toothed or scratched moisture meter scanning platform can prevent the meter from contacting the surface of the material you are testing smoothly. This removes the accuracy of moisture reading. Broken or rusty contact pins may not lead the electricity as quickly — increasing resistance to dry materials.

Another problem with a moisture meter that can impact precision is a low battery moisture meter. Weak batteries can prevent the meter from working correctly. It can even cause permanent damage to the meter over time by using a meter with depleted batteries.

Making Sure That You Read The Moisture Meter Correctly

Some higher-end humidity meters can switch between different read scales of moisture. However, it can lead to incorrect readings as conveniently as this function is. It will happen if the consumer holds the meter in the wrong reading scale when checking certain products.

One of the ways to understand moisture meter readings and achieve accurate results is to consider the meter’s ability and to ensure that the meter is in the appropriate reading mode. Therefore, please check which reading mode the meter is in before starting work on any moisture testing task.

Also, it is essential to check the species correction feature for the meter for the wood moisture meters. Different wood types can have different physical characteristics that could alter moisture measurement results. To ensure accurate readings, a wood species correction is necessary for the moisture test results. Like in scales for reading moisture, it is essential to verify that you apply the correct species correction before moisture testing in wood starts.

Final Words

Over time, a moisture meter can fall out of calibration through repeated use or accidental damage and lead to inaccurate moisture test results. It is, therefore, necessary to test the accuracy of a moisture meter before you use it.

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