(Editor's Note: This is the third installment of a series that examines building materials and the moisture meters needed for accurate measurements.
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If there's one material that has earned its designation as a mainstay in construction, it's wood.
Going back to the first structures ever made, as a strong material in ample abundance, wood has been there. And while today's construction methods and materials have advanced far beyond what our ancestors used, wood is still one of the most widely-used building materials.
Considered a "living material," wood has a unique relationship with moisture. In a sense, it's able to interact with moisture in a way other materials don't. In construction -- or other applications, such as flooring installation or flood damage restoration -- wood's ability to absorb or release moisture matters.
But as with any material, it's important to understand how to properly measure moisture content in wood in order to ensure that it's within acceptable levels. Though it might seem like the best tool for measuring moisture in wood is a moisture meter for wood, not so fast.
Let's take a closer look at why.
Go down any aisle where moisture meters are in stock, and you're sure to find meters that advertise being made for very specific uses, including:
While a meter may be designed with a specific application in mind, the fact is the majority of moisture meters take readings across a variety of materials. In other words, a concrete moisture meter won't limit you to using it only with concrete. To that end, moisture meters billed a "wood moisture meter" (or even "timber moisture meter") is a misnomer -- there really isn't a meter that's made specifically and only for wood.
Ultimately, when you're in the market for a wood moisture meter, your best bet is to invest in a professional moisture meter.
Wood, however, sets baseline standards for moisture meters, no matter their advertised purpose.
A hydroscopic material, wood is reactive with moisture in its environment, meaning it absorbs or releases moisture until it’s in equilibrium. When a piece of wood reaches this point, it's possible to measure its equilibrium moisture content (EMC). The equilibrium moisture content of wood can be thought of as an indicator of how water-reactive wood is, and it's a key factor in determining the physical properties of wood. Generally speaking, EMC is more of a guideline, rather than a hard-and-fast number.
EMC however, lends itself to another important measurement for professional moisture meters -- wood moisture equivalency (WME).
The standard for moisture meter measurement, WME is a way of quantifying the amount of water contained in a material -- say, concrete -- as if it were wood.
At a basic level, WME takes into consideration the amount of water that would need to be added or removed for the material to reach the same level of moisture as wood. This is important since different materials can have quite different levels of moisture depending on their composition, which can influence how they react with other substances or elements.
While wood is a good barometer for measuring moisture in other materials, readings can get more finite with the material itself. In certain cases -- primarily with wood flooring -- it's important to understand the differences between wood species and the amount of moisture they're likely to contain.
For example, hardwoods such as maple and oak are more reactive to moisture than softwoods such as pine and cedar. This means that their EMC is lower, but also that they will be more affected by changes in relative humidity -- an important consideration when installing flooring as planks may change size from the amount of moisture they're holding.
Resource: Curious to learn more about meter readings and wood species? Check out our article: Professional Moisture Meters & Wood Species Calibration
Again, a wood moisture meter is no different than a professional moisture meter. So whether you're using it to exclusively test wood or plan on taking measurements on other materials, a dependable wood moisture content meter’s features include:
How does a moisture meter for wood work?
That’s simple – no different than any other professional moisture meter, be it a pin type or pinless meter.
With a pin-type meter, simply touch its probes to the wood surface and take a reading. Be careful to not force the pins into the wood, as the additional pressure can damage the pins or cause inaccurate readings.
Taking measurements with a pinless meter is also simple. When using a non-invasive moisture meter, make sure its contact plate is against the wood's surface and take a reading.
Resource: What should you take away from your measurement? Check out our article: Moisture Meter Readings: Taking & Interpreting Accurate Measurements
Wood is a popular building material for good reason -- it's strong, durable, and versatile. However, in order to ensure that wood can be used effectively in construction or other applications, it's important to understand how to measure moisture content in it properly and with the right tools.
With a professional moisture meter, you can easily & accurately measure the moisture content of wood to ensure that it's within a safe and acceptable range.
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