Hardwood Floors October/November 2025

AT THE SITE

WHAT IS HYSTERESIS? A DEEP DIVE INTO ACCLIMATION AND WHY WOOD FLOORS OFTEN GAP PERMANENTLY

THE EVOLUTION OF ACCLIMATION METHODS In full disclosure, I don’t know the exact history of how acclimation was done in the early days of twentieth century, but based on the 1907 maple floor in my own home, my guess is that it was not. There are some common methods for acclimation that I’d like to address here: The first is the “leave the wood in the house for seven days prior to installation and you will be good” method. I would say that today, among non-NWFA members, this is still the most pervasive method for acclimation. The problem is that if the house is not within normal living conditions during that period of time, you could be installing the floor too dry or too wet, leading to either gapping or cupping. It also does not take into account your starting point for acclimation.

In 2021, I joined the NWFA. This was a decision that was built out of frustration from issues occurring on jobsites that usually involved distributor reps coming out to jobsites to tell me how I had installed the flooring incorrectly. At this point, I had been installing wood floors (on and off) since 2011. I knew I needed to relearn the basics, so at the very least, I would have a leg to stand on when jobsite issues arose and to answer lingering questions I had about things that I was seeing in the field. Among the most recurring of these questions revolved around why every aged floor that I saw had gaps that aren’t closing, regardless of the time of the year.

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