Rethink Acclimation

Acclimation generally is defined as the process of becoming accustomed to a new climate or new conditions. It also commonly is referred to as “adaptation.” For humans, acclimation could be the process of going from a low altitude (sea level) to a higher altitude (mountain peak) or how someone would need to adjust their lifestyle when moving from the city out to the country. Acclimation is about adjusting to something new.

For decades, the wood flooring industry has taken this word and used it to acknowledge the preparation for wood flooring going in a home where it will be installed. Although this is partially appropriate, it isn’t accurate for our industry. This article is intended to show how and why the wood flooring industry has a misdirected perspective of what “acclimation” means and why we should rethink how we use the term.

• Old NOFMA publications stated, “Acclimation is the process that results in
  flooring adjusting to the surrounding environmental conditions.”
• In the 2007 version of the NWFA Installation Guidelines, we stated that acclimation is “…to allow the moisture content of the wood to adjust to the installation site’s ‘normal living conditions’ – that is, the temperature, humidity conditions, and moisture content that will typically be experienced once the structure is occupied.”
• In the 2016 version of the NWFA Installation Guidelines, we stated that acclimation is, “The process of adjusting the moisture content of the wood flooring to the environment in which it is expected to perform.”

“Adjusting the wood” is where we get in trouble and why our industry needs to begin rethinking what this old-school state of mind is insinuating. It insinuates that the new wood floor must be altered to be installed. It is a rare scenario where we would need to alter the wood in order to install it.

Wood is a hygroscopic material. This means that when the wood is exposed to air, it will dry out or pick up moisture until it is in equilibrium with the temperature and humidity of the surrounding air.

Wood is also an anisotropic material, meaning it shrinks and swells differently in each direction. When you adjust wood, it will change its dimension. This is evident on an already installed floor when the wood gains moisture and it swells and cups. Or when the wood loses moisture and shrinks and gaps.

Before installation, if you allow the wood to swell or shrink before installing it, you can expect it won’t go together tightly. Homeowners don’t like gaps in their newly installed wood floors.

Wood is manufactured to a specific tolerance. Those tolerances tell us what to expect when specifying a floor to be placed into service. Those tolerances may even allow for some slight variations in width. Installers and consumers reasonably expect the flooring they have purchased to be within those tolerances. When wood is outside of those tolerances, it won’t go together as intended and won’t likely produce an acceptable result.

So why would we bring flooring to a jobsite and then let it change to fit the facility’s environment? Shouldn’t we require that the facility be brought up to the specifications of the products going into the home? Rather than adjusting the wood to the home, get the home adequately prepared to receive the wood. As long as the home is within these parameters, the floor may be delivered and installed.

This is the simple alteration necessary to use the term “acclimation.”

So why would we bring flooring to a jobsite and then let it change to fit the facility’s environment? Shouldn’t we require that the facility be brought up to the specifications of the products going into the home? Rather than adjusting the wood to the home. Get the home adequately prepared to receive the wood. As long as the home is within these parameters, the floor may be delivered and installed.

Wood flooring must be installed in an environment that reflects the expected in-use conditions of the home. The flooring manufacturer defines what those conditions must be for that flooring to perform as intended. Most manufacturers also provide instructions and warranties based on the flooring remaining in those stated conditions.

NWFA Installation Guidelines, 2019 version, has taken this into account with what is written.

“The process of aligning the wood flooring and the environment it is to be installed in is defined as acclimation, or more accurately, conditioning. This process involves understanding that the wood flooring and the facility are compatible.” This is followed by an entire section that details the jobsite requirements.

Further, NWFA guidelines clarify that it is the responsibility of the builder or specifier to ensure the facility is capable of sustaining an environment conducive to the building materials being used in it. This isn’t exclusive to flooring; this is for every product being installed in the home. The jobsite must meet or exceed all wood flooring manufacturer requirements and NWFA Guidelines prior to wood flooring delivery and installation. It is the end-user’s responsibility to maintain those requirements for the life of those floors. There are always exceptions to the rule. There are many scenarios where wood has been specified, and the jobsite conditions will be outside the manufacturer’s requirements.

For additional information about acclimation, check out the NWFA’s Installation Guidelines at nwfa.org/technical-guidelines/.

If you can account for these scenarios, you can price in the additional time and work necessary to make the flooring project successful.

The next time you have a customer asking about “proper acclimation,” lead the conversation about whether their home is capable of sustaining the environmental requirements that will be necessary for the flooring they want. Don’t allow the discussion to go down the road of figuring out what you need to do to the flooring to prepare it for their home.

Brett Miller is the vice president of technical standards, training, and certification for the National Wood Flooring Association in St. Louis. He can be reached at brett.miller@nwfa.org.