Prior to installation a hardwood floor needs to acclimate to your environment. Which means that the wood flooring’s moisture content and temperature needs to come into equilibrium with the environment in which it will perform.
Before flooring is installed, the moisture content of the sub floor should be within four percentage points of the flooring that will be laid on it and within two percent if laying plank flooring.
For instance if you have a plywood subfloor you would measure the moisture content with a moisture meter. Around the Puget Sound area it could range from 6%-12%. Then you measure the moisture content of the flooring which usually comes in at 6%-8%. If your subfloor comes in at 12% and the flooring is at 6% you would need to let the flooring gain moisture and balance out at 12% or else a 6% rise of moisture content in the flooring after installation will cause the flooring to swell and cup.
If you do moisture testing on the subfloor and find readings closer to 20% or higher then you have an excessive moisture problem that needs to be remedied before the flooring is brought into the home to acclimate.
Wood Flooring has a comfort level
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 60 to 80 degrees. This gives the flooring a moisture content range of 6 to 9 percent. Even though some movement is to be expected within this range, percentages outside of this range will cause drastic effects on your hardwood flooring.
To help your floor perform at an optimum level keep your heat and humidity constant throughout the seasons.
Swings in temperature and humidity will affect the floor. The more drastic of the swing the more the floor will react. It is typical to have hairline cracks in the floor in the average home during the winter time. This is due to the fact of having the house closed up and running the heat which lowers the humidity. In the summer the house is opened up and the humidity goes up, the wood swells again and the cracks disappear.
We have a wood stove which provides wonderful heat but it is a dry heat as well. The wood around the stove would always shrink in the winter and we’d have small cracks in-between the boards. In the summer the cracks would be nonexistent. It was something we were aware of and didn’t let it bother us. We were the only ones to notice it.
It is important that if you take a vacation in the winter time do not turn off your furnace. If a floor goes from 75 degrees down to 50 or less, you will shock it and it will move on you.
If you are having a floor installed do not store the wood in the garage or outside shed. You want it in the environment that it will be installed in. Dense and exotic woods will take longer to acclimate usually a minimum of two weeks or longer. The same goes with Bamboo especially the Strand variant.
The moisture content of laminate flooring is not measured but it requires the same environment as a wood floor and typically requires an acclimation period of 48-72 hours.
It is important to note that wood flooring will always move but having it properly acclimated especially before installation will cause less problems in the future.
–Joshua Crossman, PTL Hardwoods, 253-732-4298 Serving Gig Harbor, Tacoma, Puyallup, Graham and the rest of Pierce County, along with Thurston and South King counties.