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The Best Way to Save Money While Drying Lumber

What if there was one simple way to save your lumber mill thousands (and perhaps millions) of dollars?

And not only that, but you would also deliver a better product more consistently.

Sounds like a win-win!

And it’s not a closely guarded secret or trick of the trade. It all comes down to the finer details of moisture management and optimizing the drying process.

It’s widely known that underdrying wood could hurt your business.

But overdrying wood can be just as costly, if not more. And it’s easy to do, especially with softwood.

But fear not! Using a reliable wood moisture meter and fine-tuning the drying process can help you prevent both issues and maximize the value of your lumber.

So let’s more closely look at why moisture testing can make such a difference, and how to do it properly:

How moisture content affects the quality of your lumber (and what to do about it)

You know the basics: Wood that is too wet is prone to shrinking, warping, splitting, or cracking, and wood that is too dry is prone to swelling. But there are parts of the moisture management process that can sometimes fly under the radar and affect the final quality of your product.

And because moisture management and the drying process are so different for hardwood lumber versus softwood lumber, we’ll address each type specifically.

Let’s start with softwood.

Managing moisture for the production of softwood lumber

The balance between overdrying and underdrying wood in the softwood lumber industry is a fairly small margin. Especially because drying times are so much shorter than hardwood.

Properly measuring and managing moisture content (MC) helps you find that balance between too wet and too dry. And doing so makes a big difference for your bottom line.

As you know, wood that’s too wet isn’t ready to be shipped out since it’s at risk for mold growth if a stack sits above 19% MC for too long.

But here’s the dilemma many softwood lumber producers face:

With so much emphasis on avoiding wet claims and making sure the wood is dry enough, it’s often dried more than necessary just to be on the “safe” side.

So overdrying may be occurring much more often than you might think, and it could be significantly decreasing the profit of your operation.

Here’s why.

Avoid “overcorrecting” by overdrying

If lumber is tested for moisture at the end of a drying cycle and you find that it’s still too wet, the kiln can be restarted. The wood itself still has all its value and integrity.

But for overdried wood, that integrity has passed a point of no return.

Overdrying causes irreversible damage like splitting, cracking, or warping, which causes degrade, which means many of those pieces of wood will end up in a lower grade, causing the value of the wood to be significantly reduced and sold at a lower price.

So overdrying causes a considerable loss of profit, and you may also be using more energy than necessary because of longer drying times.

So rather than just making sure the lumber gets fully dried, you want to dry it to a specific target MC. And since mold can begin to grow in softwood lumber if the MC is above 19%, you want to dry the wood to just below that moisture level.

Managing moisture for the production of hardwood lumber

Hardwood and other specialty types of wood need to be dried to an even lower MC than softwood lumber. The target range is typically somewhere between 6–10% MC, depending on the equilibrium moisture content (EMC) of the wood’s final location.

You’ll need to look up the EMC for the wood’s final destination and use that as your drying target. Or, the wood should be dried to the moisture content that is specified by the end user.

Otherwise, damage or warping could occur in the final product, if the final product’s MC does not match the environment of its new home.

Additionally, since the drying times for hardwood are much longer and the wood is dried to a much lower MC, it’s a good idea to take moisture measurements an extra time or two throughout the drying process. That way you can tell if everything is on track, or if some adjustments might be needed.

So no matter which type of lumber you produce, it’s worth the investment to carefully monitor the drying process. And the best way to do that is to test your lumber with a reliable moisture meter.

Wood moisture meter options for lumber producers

As a lumber producer, you may have several types of moisture meters to consider: in-line (if your operation has a dry sorting line) or in-kiln moisture meters, and handheld moisture meters. Within the handheld category are also pin and pinless meters.

Many lumber mills have a variety of moisture meters on hand. Let’s look at each one in more detail:

In-line and in-kiln moisture meters

An in-line system is the most effective way to measure the bulk of your lumber as you dry it, run it through a planer, or process it through the conveyor system or chain deck.

An in-kiln system allows you to be alerted when the wood has dried to the final moisture content. Some in-kiln systems are programmed to shut down the kiln when it has reached the target moisture content.

An in-line system fits onto a chain deck and contains sensors that measure MC as the lumber passes over it. Or, an in-line system can be installed on the outfeed of a high-speed planer.

Though these systems are an initial investment for a sawmill, the amount you save from automatically checking the moisture content of every piece of lumber will quickly make them worth it.

However, they are not the only way to check the lumber’s MC. Some mills, especially smaller ones that do not have a chain deck or conveyor system, choose to use handheld meters to determine the moisture levels of the wood being dried.

Handheld moisture meters

Handheld moisture meters are smaller devices that allow you to measure the MC of wood by moving them onto the wood by hand. They can be either pin-type or pinless.

Pin meters have two metal pins that are pressed into the wood to measure the MC. They work best when you’re measuring:

  • Small quantities
  • Softer wood species
  • Wood with rough parts or very few flat surfaces available for measurement

Pinless moisture meters allow you to quickly scan the wood without leaving pinholes. Use them for:

  • Large loads of wood
  • Harder wood species
  • Flat boards

At some lumber mills, an employee will use a pinless moisture meter to quickly scan boards on a chain deck.

How to choose a wood moisture meter for drying lumber

Considering how crucial moisture measurement is for lumber producers and sawmills, you’ll want to have a reliable wood moisture meter for the job.

You may choose an in-kiln or in-line system if you have a conveyor system, but if you’re not ready to make the investment, then a handheld wood moisture meter is the place to start.
For larger producers, having a good handheld moisture meter in addition to in-line systems helps you to more closely track your lumber’s progress toward its target MC, and it also allows a person to verify the calibration of the in-line system.

Here are some factors to consider when choosing a handheld meter.

Accuracy

As you can guess, accuracy in a moisture meter ensures that the number you see on the screen is close to the actual MC of the wood. Not all moisture meters are created equal, and some are able to provide much more accurate readings than others.

When you’re drying lumber, an accurate, high-quality moisture meter will help you know when the wood has truly dried to its target MC. Otherwise, you might think the wood is ready when it really isn’t.

Even just a couple percentage points off could mean the difference between dry or overdry when measuring softwood, or between shrinking or swelling occurring when a shipment of hardwood reaches its final destination.

So, how do you know if a meter is accurate?

First, make sure you’re buying the meter from a reputable company. A solid warranty (at least one year) will help you know the company stands behind its products. The company may also have third-party tests that can speak to its accuracy.

Second, check that the meter has a way for you to verify its calibration. Even a quality meter, if it’s not properly calibrated because it’s been dropped, can skew the readings.

At the very least, the meter should come with a calibration verification block for you to check.

Species and temperature correction features

Different species of wood have different densities and chemical properties. Those differences can impact the results you get on your moisture meter.

Moisture meters are often calibrated to Douglas fir. A good meter should have a setting that will correct the readings based on the species you input.

Some pinless meters aren’t significantly impacted by temperature, but pin meters are (whenever you’re not measuring at room temperature). To account for this, pin meters should have a temperature correction feature or come with a correction chart for when the wood is not close to room temperature.

Ease of use and efficiency

When you’re working with large quantities of wood, you don’t want to be fumbling around with a meter that’s complicated or slow.

So, look for a meter with a simple user interface.

Ideally, for larger volumes of wood, you’ll want a pinless meter that allows you to quickly scan board after board. Not one that requires you to push pins into the wood, which can be particularly challenging when working with hardwoods.

Also, if you need to check your wood during its drying process in the kiln, consider finding an industrial meter that has a stack probe attachment. This way, you can put the probe in between boards and take readings in the middle of a stack, where boards tend to be wetter than at the outside of the stack of wood.

Durability

The moisture meter you choose should be designed to handle a rougher industrial environment.

Price

Naturally, we want the best bang for our buck when we’re shopping for a tool. Be cautious with moisture meters, though. If you’re looking for precise and accurate readings, a cheap meter isn’t going to cut it since cheap ones are often many percentage points off from the actual MC of the wood. (And just a few percentage points could mean the difference between mold growth or not.)

By limiting your search to cheaper meters, you will likely be getting a tool that won’t give you the accurate results you need.

Next, we’ll cover a few more details about using a handheld moisture meter for wood.

Tips for using a handheld moisture meter for lumber

Pinless wood moisture meters are quick and easy to use. Just set your meter to the correct species for the wood you’re testing and you’re ready to go!

Firmly press the meter on the boards of wood for an instant reading. Take a sampling of multiple boards to get a good representation of the whole load.

For a pin-style meter, you’ll also want to input the species of wood you’ll be testing. Push the pins into the part of the wood you want to measure, then hold the meter steady until the reading is displayed. For thicker boards, you will need a meter that has long pins that can be driven into the wood with a hammer probe.

You will need to insert the pins in multiple places to get a big-picture idea of the wood’s MC throughout the stack of wood that you’re measuring.

Lumber drying and moisture testing go hand in hand

Whether you kiln dry or air dry your lumber is a decision you’ll make based on the time and space you have. But regardless, moisture testing will be part of that process, helping you to know exactly when your wood is ready.

An accurate wood moisture meter is your ticket to properly dried, high-quality lumber.

Learn more about wood moisture meters and the best options on the market by taking a look at our buying guide.

Frequently asked questions

Still have questions about lumber drying and moisture testing? For quick reference, here are a couple of common questions and their answers:

How do I know when my lumber is dry enough?

Using a moisture meter will help you know when your lumber has reached the target MC, or how much more it needs to dry. If using a pin meter, press the pins into the lumber to get a reading. With a pinless meter, all you have to do is scan the wood and compare the reading to your target number.

How often should I check the moisture content of my wood?

The frequency of moisture testing will depend on the type of wood you’re drying and how you’re drying it. For kiln drying, consult your kiln schedule. You can also get valuable advice from wood-drying workshops and discussions with others who have dried similar species before.

But regardless of how often you test during the drying process, be sure the wood has reached the desired MC before you send it on for further processing.