Hardwood flooring acclimation
Acclimation of Wood Flooring
How many days does wood flooring need to acclimate before installation?
Three days? A few days? Those are common answers floating around the Internet, and even in the minds of some in the wood flooring industry.
But they are wrong answers – except when they are right.
That’s not black and white, is it? Neither is acclimation, because there are a few variables that must be taken into account. But acclimation is easy to accomplish when you understand the variables involved.
Variables of Wood Flooring Acclimation
Acclimation is specific to each wood flooring installation job. Here are the key variables that influence what it takes to properly acclimate wood for any given installation:
> Manufacturer’s instructions (Warranties depend on following them)
> Wood species to be installed (Tropical or domestic?)
> Moisture content (What’s right for your region?)
> Home environment (Consistent temperature and relative humidity)
Definition of Wood Flooring Acclimation
Acclimation is the process of conditioning the wood flooring to the environment in which it’s expected to be installed, by bringing the moisture content of the wood flooring into balance with its home environment.
Storage of Wood Flooring for Acclimation
Read and follow the flooring manufacturer’s instructions for product-specific information, and so not to void the product warranty.
In general, to acclimate wood flooring for installation, it must be stored at the jobsite, enclosed in climate-controlled conditions in the space(s) in which the flooring will be installed.
Do not store the wood in uncontrolled environments, such as a home-building construction site that has not been enclosed or had heating and cooling systems installed and turned on.
Do not store the wood in a garage or on an exterior porch.
The flooring should be unpackaged. It’s a good idea to cross-stack the boards to allow air to circulate on all sides of the boards.
Ideal Climate Conditions for Wood Flooring
The ideal home environment varies across geographic regions. Acclimation in the highly humid South will differ from acclimation in the highly arid Rocky Mountains. A wood flooring professional should understand his/her home region, and its ideal conditions in low and high moisture seasons.
Proper moisture content should be reached with the home temperature being maintained between 60 and 80 degrees Fahrenheit, and with relative humidity in the home typically being maintained between 30-50 percent. The disclaimer: Manufacturer instructions and geographic climate zones can cause the ideal relative humidity to shift higher or lower. Consistency is king.
The National Wood Flooring Association (NWFA) publishes maps by the U.S. Department of Agriculture, Forest Products Laboratory that show moisture content by area of the United States and Canada.
For example, the ideal climate for most of Colorado requires six to seven percent moisture content for wood flooring. The state’s western area is even drier, at five to six percent.
More examples: Florida’s moisture content should be 12 to 13 percent, while Michigan’s ranges from seven to 11, and Nevada ranges from four to seven.
Tropical species often require more time for acclimation than do domestic species. Some tropical species gain or lose moisture at different rates than domestic species due to higher overall density, oil and resin content, and cell structure.
Testing Moisture Content for Acclimation of Wood Flooring
When wood flooring is delivered to a job site for acclimation and installation, the moisture content of the wood should be checked using a moisture meter. The flooring should be unbundled, and a representative sample should be tested to establish a baseline for the wood’s moisture content at that time.
A typical sample size is 40 boards per 1,000 square feet of flooring. Compare the average moisture content readings for the sample against the ideal for your region.
When the moisture content of the wood flooring matches the needed moisture content level for installation in your region, the wood is ready for installation.
If upon delivery the moisture content readings already show a level appropriate for that region, then immediate installation is possible.
If the moisture content is well outside the range of the optimal condition, that flooring might need to be rejected, as the flooring will begin to fail even during the acclimation process.
For example, if the wood is delivered to the job site having only been dried to 12 percent by the manufacturer, but you need the wood to be acclimated to six percent, failure is likely to occur. Floor failures could include: excessive shrinkage, bowing, cupping, and other physical anomalies.
If the wood has been dried properly by the manufacturer, moisture content readings should be reasonably close to what is required for installation. And a short period of time for acclimation will prepare the wood floor for installation.
For example, Palo Duro’s manufacturer partners typically dry wood flooring to five to eight percent moisture content, depending on the manufacturer. Acclimation for installation in Palo Duro’s home state of Colorado is easily achievable from those levels.
The Bottom Line: Acclimation of Wood Flooring
Only one number determines when wood is properly acclimated: moisture content.
The number of days is irrelevant, because there is no magical, black-and-white number of days that works in all situations.
If the wood reaches the needed level of moisture content through acclimating to its home environment in one day, or in three, seven or 10 days, then that is how many days that particular wood flooring requires in that particular home setting.
Acclimate wood flooring as long as necessary to reach the proper moisture content level.