A Sawmill’s Guide to Using Moisture Meters

Moisture meters are a must for any sawmill that dries its lumber.

While the drying end of large sawmills might use an in-line moisture meter that sorts wet and dry wood after it’s been kiln-dried, many smaller-scale operations may rely more on handheld meters.

Either way, if you’re drying your lumber, moisture measurement and management are crucial.

What if you left wood in the kiln for just a bit too long and it developed significant degrade?

What if you lost customers after selling them wood that still had just enough moisture left in it to warp, or start growing mold after they received it?

It’s frustrating for all that hard work to end up falling prey to degrade or moisture damage.

But a trustworthy moisture meter can help you prevent these problems by telling you how much moisture your wood contains. This can help increase product yield and decrease product loss.

But what kind of moisture meter do you need? And what’s the best way to use it to verify that the wood is properly dried?

Let’s look at:

• The benefits of using moisture meters
• How they’re used in sawmills
• What moisture meters you’ll need
• Where to buy a high-quality moisture meter

Let’s start by understanding the importance of measuring wood moisture.

Why Use Moisture Meters?

Moisture meters help the dry end of a mill ensure high-quality lumber.

Wood is a hygroscopic material, so the structure of the wood changes in response to the amount of moisture it’s exposed to. If it’s in a humid environment, it will soak up moisture and swell. If it’s in a dry environment, it will release the moisture it contains, causing the wood to shrink.

To avoid this wood movement and produce quality products, sawmills must take moisture content into account, ensuring that the wood is at the appropriate moisture level for its end-use.

Typically, smaller sawmills serve local or specialty markets and produce lumber for furniture, cabinetry, or smaller woodworking projects where moisture management is critical. The type of wood used for these purposes (often hardwood) is very sensitive to changes in moisture content. Even a small amount of shrinkage or swelling can affect fit, quality, appearance, or performance.

Because of this, sawmills that provide this type of lumber need to dry it down, as close as possible, to the equilibrium moisture content (EMC) of its final environment. While EMC varies by regional climate and indoor conditions, a commonly accepted range for interior furniture is 6-8%.

Larger industrial sawmills, on the other hand, are more likely to produce softwood lumber for construction, and the acceptable moisture content range isn’t as small. Although wood movement is still a consideration in construction, building methods and standards can allow for some drying or acclimation time. So lumber used for construction is often purchased at a higher moisture content than lumber intended for furniture.

However, excess moisture could still lead to considerable problems like mold growth or post-installation shrinkage, which is why construction lumber is dried to below 19% moisture content.

While small sawmills have lower moisture content goals than large sawmills, both sawmills want to avoid underdrying or overdrying their wood. Underdried wood could grow mold or shrink unevenly, and overdried wood could become brittle and weak, leading to wood degrade and a loss of profit.

Fortunately, high-quality moisture meters give sawmills the readings they need to determine when their lumber has reached the proper moisture levels, which helps:

• Prevent moisture damage, mold growth, warping, or degrade
• Optimize drying time and streamline sales:
  • A moisture meter can tell you when the wood is ready to sell. By checking the wood regularly, you won’t waste any time waiting to make a sale (or waste time and money drying wood that’s already dry).
  • Knowing the moisture level of your wood can also help in drying wood more efficiently. Moisture meters show you which boards contain the most moisture. This information can help you pinpoint boards that may need special attention so you can speed up the drying process.
• Meet product quality standards:
  • If you sell wood that hasn’t been fully dried and your customer uses it to build something, and then their project develops moisture damage or mold…that ruined project leads to an unhappy customer.
  • If a customer can’t trust you to dry lumber properly, they might take their business elsewhere. And chances are, they’ll tell others to do the same. But if you can prove you’re dependable by producing consistent, high-quality wood, they’re more likely to bring you new business.

There’s no question that a trustworthy moisture meter helps ensure production of high-quality lumber your customers are sure to come back for.

How Sawmills Use Moisture Meters

Sawmills benefit from using handheld moisture meters throughout the drying process.

• You can verify when the wood’s been dried enough in the kiln: Use a moisture meter to determine whether your wood has reached the proper moisture content. Checking this regularly helps prevent over drying the wood, which can waste time and resources.
• You can take confirmation readings right before selling: The MC of your wood may change while it’s waiting in storage. It’s important to double-check the moisture of your wood before selling it to make sure it’s within the proper moisture range. (Doing this in the presence of customers also demonstrates your commitment to quality.)

Next, let’s get more specific about the kind of moisture meter your sawmill needs.

Understanding which Meter You Need

The perfect meter depends on the needs of the dry end of your mill.

Bigger lumber producers may want to use in-line moisture meters. These large systems can read the moisture content of each board automatically as it moves along a conveyor belt.

Smaller operations (or even big mills that want to double-check moisture content) will want to use handheld moisture meters.

Unlike in-line meters, handheld moisture meters are small and compact. You can bring them with you wherever you go. Their user-friendly interface also makes them easier to use.

If you’re interested in hand held meters, you need to decide whether to get a pin meter or a pinless meter.

Pin meters come with metal pins that need to be pressed or pounded into the wood to get a moisture reading. Once inserted, the pins send an electric current to measure the wood’s moisture based on the electrical resistance in the wood.

Meanwhile, pinless meters, as the name suggests, don’t have pins. Instead, they have a sensor plate on the underside of the meter that, when pressed against wood, sends out an electromagnetic pulse to get a moisture reading. It is also much quicker and easier to measure a large volume of wood with a pinless meter.

There are pros and cons to each option.

Pin-type moisture meters might be cheaper, but they aren’t always as accurate as pinless meters. They can also leave unsightly holes in your wood and measure a smaller area.

Pinless moisture meters, on the other hand, might be more expensive, but they’re usually more accurate and more convenient to use. You don’t have to spend a lot of time driving pins in multiple places. Instead, you can get readings at the push of a button without leaving pinholes behind.

Decide which type of meter is best for you, then you’re ready to make your purchase.

Want to make sure you’re up-to-date on the best way to use a wood moisture meter?

Here’s a guide to pinless meters.

And here’s a guide for fully understanding moisture readings.

Get Your Mill a Reliable Meter

Build your reputation as a sawmill dedicated to high-quality lumber by making wood moisture management a vital part of your daily routine.

The first step is choosing a meter you can count on.

No matter the size of your operation, we recommend handheld pinless meters for your industrial environment for smooth wood and measuring larger volumes of wood. Compared to pin-style meters, these will save time and effort while contributing to the peace of mind that your lumber is ready to sell and free of pin damage. If you have rough wood or curved surfaces, a pin meter will be the meter that you need.

Get a quality meter for easy, accurate, and efficient results.