Best Practices for Acclimating Hardwood Flooring

Previously published by Tomorrow’s Contract Floors

Some high-quality pinless meters, such as the Orion 950, make it easy to know when your hardwood flooring has reached EMC and is ready to install.

No doubt, you want everything to be just right when preparing to install a hardwood floor. Which is why you’ll want to avoid a common and very serious misconception about moisture in wood—a misconception that could wreak havoc on your floor after it’s installed.

The misconception? Some contractors believe that if you bring wood flooring to the job site and let it sit for a few days, it will acclimate properly and be ready to install. This belief is simply not true. Sure, this approach works much of the time. But there will be instances when a few days won’t be enough. In those situations, if you go ahead and install, you may end up with a moisture-related flooring failure and costly repairs.

Something, of course, you’d want to avoid! So, how can you be assured that you’ve waited long enough for the wood to acclimate properly?

Let’s take a close look at these three best practices.

Prepare your job site

Once the hardwood flooring has been chosen, it’s only natural to want to bring it to the job site to acclimate as soon as possible. But be careful! You’ll want to verify that certain conditions have been met before the hardwood flooring gets delivered.

A controlled environment is best for wood storage, even in the short-term. Make sure both on-site temperature and relative humidity (RH) are stable and at or near service conditions. To help accomplish this, you’ll want the building to be completely enclosed with the heating and/or air conditioning up and running.

The idea here is to prevent extreme shifts in the flooring’s MC. Significant, sudden, and/or repeated changes in MC may harm the integrity of the wood.

Check your wood’s moisture content and compare to EMC

When the hardwood flooring arrives at your job site, your first task is to check its MC using a high-quality, moisture meter (a non-damaging pinless moisture meter is preferred) capable of taking accurate measurements down to 5-6% MC. Check at least 40 boards for every 1,000 square feet for a good baseline representation of the flooring’s MC. These readings may even help you estimate how much time you’ll need to allow for your wood to acclimate to be ready for installation.

Along with a moisture meter, you should also use a thermo-hygrometer to measure the ambient temperature and RH. Some moisture meters come with this capability built in. For example, the Orion 950 by Wagner Meters not only monitors ambient conditions (temperature and RH), but it also uses this information to calculate the equilibrium moisture content (EMC) for you. Plus, the Orion 950 even stores your data for review later.

EMC is extremely important because this is your target moisture level indicating when the wood has fully acclimated to the surrounding environment. You want the wood’s MC to be within 2% of EMC before installing the hardwood flooring.

Don’t forget the subfloor

Aside from the MC of the wood, you’ll also want to pay attention to the subfloor. If it’s concrete, for example, a surprising amount of moisture may be lurking deep inside the slab. Never assume the concrete is sufficiently dry just because the surface appears dry. And this means: don’t rely on a moisture meter, which only takes measurements near the surface of the concrete and typically only gives relative readings. An in-situ RH test is needed to get accurate, reliable moisture measurements.

Bottom line: How long does it take to acclimate hardwood flooring?

Hardwood flooring could acclimate in three days, at minimum, assuming the interior space is at service conditions. However, never count on it since acclimation times can vary. Use a pinless moisture meter to check and monitor the MC of the wood and compare your readings to the calculated EMC.
By following these tips, you can be certain that you are installing properly acclimated hardwood flooring. And that, in turn, will help ensure success—giving you a beautiful, long-lasting floor and satisfied customers.

Find more information about moisture in wood or concrete, or to learn more about the Orion 950 moisture meter.