The point of acclimating wood flooring prior to installation is to allow the moisture content of the wood to adjust to “NORMAL LIVING CONDITIONS” at the site; that is, the temperature and humidity conditions that will typically be experienced once the new home moisture is removed and the structure is occupied. We manufacture our hardwood flooring to a moisture content between 6% and 9%. Going from the temperature and humidity chart (in Chapter 3), 40% humidity creates a wood moisture content of 7.7% which is in the centre of the range. In the North Eastern Region, where we are located, is the centre of the range that a house should be in after the “new home” moisture is removed. Other regions may require periods of acclimation to bring the wood within 2% of the subflooring. Our warehouse is climate controlled to a relative humidity as close to 40% as possible. This range is the most comfortable and healthy for humans. In most cases, our flooring is ready to install immediately after delivery. If your home is within this range the wood is going to remain the same whether it is in our temperature controlled warehouse or in your home. Our climate, in the Northeast, is very dry in the winter and very humid in the summer. When flooring is acclimated too long in the extreme dry winter conditions and installed when it has shrunk, it will expand excessively and possibly cup when the humid season arrives. If the flooring is acclimated to high humidity conditions and installed when it is expanded when the dry season returns the floor will shrink excessively resulting in large spaces between boards. If you have a cottage that is not heated in the winter, a crawl space, a structure on piers, or any situation that may not be considered normal, please contact us at firstname.lastname@example.org. It must be understood that the wood based subfloor must be within 2% moisture content of the hardwood flooring before installation can proceed.
Having the wood flooring on the jobsite before these conditions are met will cause it to change dimensions, especially on the ends. If the humidity is higher than the recommended levels, the ends of the wood will absorb moisture first and will become wider. If the humidity levels are lower than the recommended levels, in solid wood the ends will lose moisture and shrink; for engineered flooring the top layer of wood will crack. In both of these cases problems are created unnecessarily.
Acclimation is very misunderstood. Many times I have come into situations where someone was adamant that the wood flooring needed to sit in the house 2 to 3 weeks prior to installation to acclimate. This was true ages ago, before the wood was kiln dried; the flooring had to sit in the house to complete the drying process.