Need Sales Help?

Huge Sale
Expires 5/27/2016!

Indoor Humidity and Its Impact on Flooring

Posted: July 01, 2002

Anyone who has installed wood, bamboo, laminate or cork flooring is familiar with the term “acclimation” – and if they didn’t acclimate their flooring according to the manufacturer’s instructions, they may have learned a hard lesson about warranty coverage.

Acclimation Basics

For those who are not familiar with acclimation, it is a required pre-installation process that allows the flooring material to adjust itself to the environment of its installation. The details of the process vary slightly among flooring manufacturers, but the basic concept is the same. The general consensus is to place the flooring in the room where it will be installed for 2-3 days with the temperature at 60-75° F and the humidity at 35-55%. It is important to note that the referenced humidity range is not the outdoor humidity level as stated in a weather report, but the controlled, indoor humidity level.

As the seasons change, humidity can fluctuate dramatically in some parts of the country, while other areas experience lesser swings. The desert southwest, for example, has very low humidity levels year round. In contrast, coastal regions have higher levels throughout the year. The rest of the country, especially the north, gets a taste of both extremes with humid summers and very dry winters.

Solid and Engineered Wood Flooring

Because wood is fibrous, it absorbs or releases moisture to equalizes itself to the humidity of its environment. Fiber saturation occurs when the moisture content is about 28%. As the humidity level begins to decrease, wood releases moisture, and when its moisture content drops below the saturation point, the wood begins to shrink. If the moisture content is below the saturation point and the humidity level increases, the wood will absorb moisture and begin to swell. Once it reaches its saturation point, wood becomes relatively stable. It remains that way until the moisture content reaches approximately twice the saturation point. That is why manufacturers recommend maintaining a room with wood flooring at a 35-55% humidity level.

Bamboo Flooring

Bamboo is actually a grass, but because it is fibrous, it is affected by moisture the same as wood. Therefore, acclimation and post-installation humidity levels must be controlled to maintain dimensional stability.

Laminate Flooring

Although laminate flooring is often thought of as “plastic flooring,” it is still constructed with a wood core. As such, laminate flooring is also sensitive to humidity and must be acclimated and cared for the same as wood and bamboo.

Cork flooring

Cork is not as susceptible to shrinkage and swelling as wood or bamboo, but since it is a natural product – the bark of the Cork Oak tree – it will fluctuate with humidity changes. Therefore, acclimation and continuous humidity control is recommended by cork manufacturers.

Controlling Indoor Humidity

To contend with very low humidity levels, humidifiers are used to maintain the recommended range and prevent the flooring from shrinking and separating. For extremely high humidity levels, air conditioners and dehumidifiers are used to keep the flooring from swelling and buckling.


All of the preceding information is important for two reasons. First of all, if you are going to spend a lot of time and money installing a new floor, you would obviously want to keep it in good shape for a long time. Secondly, in order to insure your warranty coverage, you must follow all of the flooring manufacturer’s recommendations to the letter.

Therefore, instead of thinking of flooring acclimation as a pre-installation process, think of it as an ongoing process. By carefully controlling your home’s humidity level you will maintain the integrity of your floor and the protection of your warranty.