Hardwood Floors August/September 2017

RESOURCES WOOD FLOOR FACTS

Acclimation/Conditioning of Wood Floors

Wood flooring is a hygroscopic material. This means that it absorbs and loses moisture in response to its environment. When there is excess humidity in the environment, wood gains moisture and it swells. When there is a lack of humidity in the environment, wood loses moisture and it shrinks. These changes are completely normal and should be expected. Ideal environmental conditions vary from region to region and jobsite to jobsite. It is the flooring professional’s responsibility to know the expected living conditions for each jobsite and adjust product selection accordingly. Some key factors to consider include the normal temperate and humidity of the building and whether or not an air conditioning and/or heating system will be regularly running. To avoid excessive expansion, shrinkage, dimensional distortion or structural damage, it is important to acclimate the floor in a controlled environment. Acclimation can be facilitated by separating the flooring bundles into small lots and/or opening the packaging. A common practice is to cross-stack the materials with spacers between each layer of flooring to allow air circulation on all sides of all boards. As a general rule, with geographic exceptions, wood flooring will perform best when the interior environment is controlled to stay within a relative humidity range of 30 to 50 percent and a temperature range of 60-80 degrees Fahrenheit.

equilibrium moisture content in the environment in which it will be installed. Acclimate the materials as long as necessary to accomplish this task, taking the necessary moisture readings to indicate when the materials have reached the proper moisture content and when no further changes occur. More-detailed information about wood flooring acclimation and conditioning is available in the NWFA Wood Flooring Installation Guidelines and Methods publication, or at http://member.nwfa.org/ default.asp?page=InstallGuidelines.

While it takes time to acclimate a product, the most important aspect is that the materials reach the

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