Wood is hygroscopic, meaning it constantly interacts with the environment. When wet, it expands. When dry, it contracts. And when the wood flooring is laid too early, the expanding and contracting nature of the wood will ruin a job with cracking, cupping, crowning, or other issues.
All wood, including hardwood flooring materials, must reach Equilibrium Moisture Content (EMC) before it is in viable working condition. But it’s not just about reaching any EMC, it must reach the correct EMC—one that is similar to the conditions of the woods’ end-use environment.
To know if the wood has reached the correct EMC, the moisture content (MC) in the wood must be measured by an accurate, reliable moisture meter.
Skipping this step is never a good idea, and in fact, it can even be a project’s downfall. Here are the top-five moisture-related threats facing your flooring business.
1. Not letting the wood flooring acclimate to its EMC before installation
When the wood stops absorbing or releasing moisture, it has reached its Equilibrium Moisture Content (EMC). But even if the wood experienced initial moisture balance, it must have time to acclimate to its end-use environment.
EMC occurs when the MC inside the wood is balanced with the surrounding environment, specifically with the temperature and relative humidity (RH).
Simply put, wood is constantly trying to reach its EMC.
To reach equilibrium in a warehouse is one thing, but the moment the wood is moved, the balance is lost and the wood tries again to reach a new EMC. And each time the wood is placed in a different environment, the process will start again.
When the wood is finally in its end-result environment with balanced moisture levels, it should still be monitored to make sure it doesn’t continue to gain or lose moisture.
After all, it’s just a waste of time and money to work with wood that hasn’t equilibrated.
2. Not testing the MC in the wood flooring
Some wood moisture meters track and record the wood’s MC so installers know the wood product achieved its EMC state. And these meters make it easy for installers to continually and accurately monitor the wood’s MC, before, during, and after project completion.
Installers need to know the MC to be sure it’s balanced because that is what assures a stable, long-lasting flooring job.
Though important, it’s not enough if only the mill is responsible for the wood’s quality. The lumber kiln-drying process is crucial in the beginning, but the quality of the wood is not permanently assured, which is why builders and installers need to continually test and monitor the wood themselves.
It could’ve been stored in a different environment than one similar to the end-use environment. And if that’s the case, you’d need to know about it.
The innovative technology of the best wood moisture meters means users can observe, measure, and record the wood’s MC faster and easier than before. And this means it can easily be done on a regular basis.
Regularly logging this information helps ensure your job because in the end, if something goes wrong (or right), the customer goes straight to you—the builder or installer—not to the mill.
3. Not inspecting the flooring
Buying kiln-dried wood from reputable suppliers is key, but once the wood is in your care, you’re the one responsible for physically inspecting the individual boards.
Even in the same species, board color variation can be wide-ranging—that’s normal.
There could also be a discrepancy in the length of the boards. But this isn’t a project-ruining problem; it’s just one to be aware of because of potential issues related to staggering. Knowing these issues in advance can help you plan accordingly.
And beyond inspecting for superficial differences, boards must be inspected for imperfections like cracking, splintering, or warping.
Remember, all these variations are to be expected when working with the unique nature of hardwood flooring. Not every piece is perfect, which is why it’s the job of the installer to strategically pick and place boards accordingly.
4. Not using an accurate/reliable moisture meter
Investing in a good, reliable moisture meter is like buying insurance. With one, you can regularly measure the MC in the wood and protect your projects and reputation.
Using a lower-end meter might save you money immediately, but if the meter returns inaccurate or unreliable test results, that will end up costing you more in the long run. Better to front the cost for a quality meter you know you can trust. That way you have confidence in every job you do.
The confidence and peace of mind you get from a quality meter are priceless. No more losing sleep over whether or not to trust your moisture meter. And that means all your energy can be poured into the quality of your work.
Then, once the job is done, continue to monitor the wood product’s MC for optimum long-term health.
5. Not following the NWFA guidelines
A successful flooring job follows both the industry-wide standards and the specific manufacturer guidelines.
The National Wood Flooring Association’s (NWFA) technical guidelines offer “industry-accepted standards and straightforward information” that helps users through every part of the installation process.
NWFA guidelines represent “all segments of the hardwood flooring industry, including manufacturers, distributors, retailers, installers, importers/exporters, inspectors, and consultants.” An example guideline goes like this:
“Strip width less than 3” allows for no more than a 4% moisture difference between finish wood and subfloor. Wider width plank 3” or greater allows for no more than a 2% difference between finished wood and subfloor.”
Guidelines like these are documented and continually updated by the NWFA.
Also, be sure to follow manufacturer guidelines. They won’t differ much from the industry standards, but they may add additional, relevant information for your particular situation.