For many industries, it’s very necessary to determine moisture content. For example, in concrete, tiles, wood, restoration, etc., moisture can affect the job negatively.
There are different methods for determining moisture content, and among them, using a moisture meter is the most popular way.
If you need to use a moisture meter, then you must have a clear idea about the chart and the different types of moisture reading scales.
In this article, I’ll discuss in detail how to interpret different moisture scales.
In this post we'll cover:
- Reference scale
- Wood scale
- Drywall scale
- Hay scale
- Paper scale
- Pin vs pinless moisture meter
- What’s a normal reading on a moisture meter?
- What’s an acceptable moisture reading?
- What should drywall moisture readings be?
- How accurate is a moisture meter?
- What’s the normal moisture level in a house?
- What’s an acceptable moisture reading for hardwood floors?
- What’s an acceptable moisture level in concrete?
- How do you calculate moisture content?
- Can moisture meters be wrong?
- What moisture level does mold grow at?
- Are cheap moisture meters any good?
- What is the most accurate moisture meter?
- Are soil moisture meters worth it?
- Know how to read a moisture meter
The moisture reading scales are designed to determine a specific, quantitative amount of moisture content (%MC) in a particular type of material. The reference scale helps to provide a qualitative estimation of moisture across different types of materials.
Some moisture meters use a range from 0-100 and others use a range from 0-300. There are several ways to use a moisture meter with a reference scale, such as:
- The reference scale is designed to use for different building materials. So you don’t need a different reference scale to measure the moisture content of different materials. A single reference scale is enough.
- Reference scales are preferred more to determine whether the material is too dry or too wet. The reading of dry material can be used as a reference in the future.
- It can be used to check the available moisture content in the soil. A popular moisture meter called Delmhorst’s KS-D1 soil moisture meter uses the reference scale (along with special gypsum sensor blocks) to diagnose the available moisture content in the soil.
From the name, it’s clear that the wood scale is used for determining moisture content in wood materials. It’s commonly used in the flooring, construction, lumber, and restoration industries.
Generally, wood scales are calibrated to cover a range from 6%-40% moisture content. There are dedicated wood moisture meters.
Drywall scales are used to determine the moisture content of construction, home inspection, and water damage restoration industries. It uses a reference scale and does a comparison with dry materials to determine the amount of moisture present.
Well-constructed drywall should have a moisture content below 1%. That’s why if the amount of moisture ranges from 0.1% to 0.2%, drywall scales can detect it more accurately.
You know that gypsum is one of the most commonly used construction materials and it’s very sensitive to water. An amazing application for drywall scale meters is checking the moisture content of Gyp-Crete flooring because drywall meters are calibrated for measuring moisture in this material.
Check out this video by YouTuber WagnerMeters to see how to use a drywall moisture meter:
As the name suggests, the hay scale moisture meter is used for detecting the moisture content of hay. The hay scale range generally remains between 6% to 40%.
It works best to measure the moisture of haystacks.
Hay scales are popular among farmers and distributors of hay.
For paper manufacturers, determining the moisture content is very necessary to produce papers of good quality.
The moisture content of raw materials used for the paper should remain in a particular range to prevent deterioration. For this purpose, the paper scale is used.
Pin vs pinless moisture meter
There are 2 main types of moisture meters: pin-type and pinless.
As the name implies, pin-type moisture meters have 2 or more pins that penetrate material. That’s how you get the moisture readings.
Pinless moisture meters don’t use any pins. Instead, they use electromagnetic waves, which means you don’t need to penetrate any material.
As you’d might imagine, they have their own pros and cons. Assess them to figure out which is the best tool for the job.
Here are some frequently asked questions and their answers.
What’s a normal reading on a moisture meter?
A normal moisture meter reading on wood ranges between 6% and 10%. However, for drywall, concrete, and masonry substances, the moisture meter should show low values (preferably less than 1%).
What’s an acceptable moisture reading?
Knowing the relative humidity (RH) conditions is a must when trying to determine what a “safe” moisture content for wood walls is. For example, if the temperature in the room is around 80 F, and the RH is 50%, then a “safe” level of moisture in the wall would be about 9.1% MC.
What should drywall moisture readings be?
While relative humidity can have some effect on moisture levels, drywall is considered to have an appropriate level of moisture if it has a moisture content of between 5% and 12%.
How accurate is a moisture meter?
A high-quality moisture meter used on the right material can be accurate to within less than 0.1% of the material’s moisture content by weight. However, a low-end moisture meter can be wildly inaccurate.
What’s the normal moisture level in a house?
It’s important to maintain the proper humidity levels in your home and workplace to keep a comfortable, healthy space. Indoor humidity levels should be between 30% to 50%, with the ideal level being about 45%.
What’s an acceptable moisture reading for hardwood floors?
To determine if your hardwood floors need to be acclimated, you can use a wood floor moisture test. First, test the moisture level of the subfloor.
In general, 12% moisture or above is too wet to install flooring. Ideally, it should be between 7% and 9%.
What’s an acceptable moisture level in concrete?
MFMA recommends the relative humidity level for a concrete slab for a non-glue-down maple floor system be 85% or lower. For glue-down systems, the concrete slab’s relative humidity level should be 75% or lower before installation.
How do you calculate moisture content?
The amount of water is determined by subtracting the dry weight from the initial weight. Then, the moisture content is calculated by dividing the amount of water by the dry weight or total weight, depending on the reporting method.
Can moisture meters be wrong?
Moisture meters are subject to false positive readings for a number of reasons that are well documented in the industry. Non-invasive meters have more false positives than penetrating meters.
The most common cause is metal hidden in or behind the material being checked.
What moisture level does mold grow at?
Sometimes, humidity or dampness (water vapor) in the air can supply enough moisture for mold growth. The indoor relative humidity (RH) should be kept below 60%; ideally, between 30% and 50%, if possible.
Are cheap moisture meters any good?
An inexpensive $25-50 pin type meter is good for measuring firewood. If you’re willing to accept a moisture reading with +/- 5% accuracy, you can probably get away with buying a cheap meter in the $25-50 range.
So a cheap $25-50 pin type moisture meter is good for firewood.
What is the most accurate moisture meter?
The Calculated Industries 7445 AccuMASTER duo pro meter is the most accurate moisture meter. The multifunctional moisture meter features a pinless pad to test a large area, plus a switch to a pin-style measurement for accurate tests that are within 3% at various depths.
Are soil moisture meters worth it?
The meters will tell you if soil is wet, moist, or dry at the root level, which make them especially effective for large potted plants. Other soil moisture monitoring tools, often used for agricultural applications, include tensiometers and electrical resistance blocks, which indicate the moisture tension of the soil.
So if they’re worth it to you will depend on how serious you are about soil moisture.
Know how to read a moisture meter
Moisture plays an important role in the production industry. Even in our daily lives, it has a significant role.
Its presence isn’t always bad; rather, in many cases, it’s useful. What we need is to keep the moisture content in a certain range.
A moisture meter is the most reliable way to determine the moisture level. There are different types of moisture meters and each type is for a specific purpose. Depending on your need, you should select the correct ones for the job.
I'm Joost Nusselder, the founder of Tools Doctor, content marketer, and dad. I love trying out new equipment, and together with my team I've been creating in-depth blog articles since 2016 to help loyal readers with tools & crafting tips.