Page 3 - 2018-07-CFR Volume 118 - The Importance of Wood Flooring Acclimation in a Commercial Setting

The Two Main Phases of Flooring Acclimation July 2018
At the highest level, there are two main phases to
ensure wood flooring is properly acclimating. First is
the environmental preparation. Wood can’t acclimate
to its environment if the environmental conditions are
not stable. The second phase is the correct method
for allowing the wood flooring to acclimate, and then
measuring its moisture content to identify when EMC
has actually been achieved.
Environmental Preparation
Since the purpose of acclimation is to let the wood
adjust to its long-term conditions, the environment
has to have reached its own steady state. This
means that all wet work is done and there are no
sources of water or moisture, such as drying paint,
that can impact the wood. It also means that any
HVAC system is functioning and there aren’t any
open spaces, like uninstalled windows, that will inter-
fere with the temperature or humidity of the space.
If you are installing solid wood flooring on a wood-
based subfloor (plywood or OSB), the moisture con-
tent variance between the two must be within ac-
ceptable limits. For solid strip flooring 3 inches and
less in width, the moisture content variance between
the flooring and the subfloor is to be no more than
4% moisture content. For 3-inch and wider flooring,
the variance is to be no more than 2% moisture con-
tent.
If the wood is being installed on a concrete slab.
NWFA recommends a maximum of 75% internal RH
or below (as determined by the ASTM F2170 test
method) in the concrete before installing the wood.
Of course, this RH measurement of the moisture
condition of the concrete is separate from the EMC
required of the wood itself that’s being installed over
the concrete slab.
Acclimating the Wood Flooring and Measuring the
Moisture Content
The first step when the flooring arrives is to measure
its moisture content upon delivery. Getting this base-
line immediately lets a contractor decide whether the
wood should even be accepted. If the RH of the
wood and the air around it is too far apart, the wood

3 Commercial Flooring Report