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Hardwood’s Worst Enemy

Most hardwood troubles can be boiled down to one word:


challenges of installing hardwood flooring

Many hardwood flooring problems are preventable simply by acclimating the wood before you install and testing the moisture condition of the subfloor.

Moisture on the floor, moisture underneath the floor, and moisture in the air can cause gapping, buckling, cupping, crowning, and squeaking. Moisture issues can make installing and maintaining hardwood quite the challenge.

Many of these challenges fit into one—or both—of these categories

  • Not properly acclimating your hardwood floor
  • Installing hardwood over a wet subfloor

Let’s talk about these in detail, and stay tuned because we will touch on one of the most reliable ways to prevent these challenges.


Gapping happens when wood hasn’t been given time to acclimate to its new setting.

Wood adapts to its surroundings by expanding and contracting. When the air is humid, wood absorbs moisture and expands. When the air is dry, the moisture evaporates, and the wood contracts as a response.

If the hardwood floor is installed before it has had a chance to acclimate, it might be too wet. When it finally stabilizes to the humidity and temperature of the space, the floor will contract, leaving large gaps between the boards.

A bit of separation between boards is normal, but large gaps indicate a lack of acclimation.

But gapping isn’t the only challenge that occurs because hardwood has not had time to acclimate.


Buckling is gapping’s extreme opposite.

Rather than gaps forming from hardwood contracting, buckling is what can happen when boards expand due to moisture..

If boards are stored at an overall drier climate than the climate of their new location, they will be in a contracted position when installed. Because the new location is more humid, the boards will tend to push each other up and off the subfloor as they expand.

Buckling can also happen if floors are improperly attached to the subfloor or if there is extreme flooding. You can’t control flooding, but following the proper installation practices is your duty.


Cupping is when a board’s edges are higher than its center, creating a concave surface.

If hardwood is installed over a subfloor—such as concrete—before the subfloor is sufficiently dry, it can absorb moisture from below. Because the underside of the board will not dry as quickly as the surface, the moisture content (MC) of the board will be inconsistent, which will result in a cup-like shape after the surface dries.

It’s generally not liquid water that causes cupping, though that can certainly happen. Often, a high relative humidity (RH) in a concrete subfloor or from below a wood subfloor will be the cause of cupping in hardwood floors.

Like gapping and buckling, cupping also has an opposite: crowning.


If cupping is caused by excess moisture underneath the board (or excessive dryness on top of the board), then its opposite, crowning, is caused by excess moisture in the top portion of the board.

The same logic applies to crowning as it does to cupping. Because the top of the plank has an increased moisture level compared to the bottom, the moisture imbalance results in crowning. Rather than a concave shape, crowning creates a convex shape, as the edges of the board curve downward and the middle rises.

While these issues are easily visualized, the final one affects a different sense: auditory.


Who hasn’t experienced a squeaky wood floor?

If a squeaky floor lasts past a change in seasons where the climate changes, it might mean that nails are loose, something is wrong with the subfloor, or the adhesive is breaking down.

All of these might be caused by a moisture-related problem.

The Solution to Your Moisture-Related Problems

One of the best things you can do to prevent and diagnose problems with wood flooring is to measure the moisture content of both the flooring and the subfloor—and if the subfloor is concrete, be sure to use an in-situ relative humidity (RH) test.

Keep in mind, though, that many other factors help limit wood flooring challenges, including:

  • Proper installation
  • Adequate fasteners
  • Moisture retarders

Instead of risking your next installation job, test the moisture content of your flooring accurately and non-invasively by using a pinless moisture meter.

smart wood moisture meter with app

One very important way to stay in control of moisture is to use an accurate, non-damaging, pinless moisture meter.

Non-damaging pinless moisture meters help you determine both the wood’s MC and the ambient RH, which ultimately guide you to making those ever-important installation and repair decisions.

If you want to avoid all the moisture problems mentioned above, an Orion pinless moisture meter by Wagner Meters is your best option for accuracy, reliability, and ease of use.

Simple Ways to Maintain the Beauty of Hardwood Flooring

Wood floors are gorgeous but not effortless to care for. Keeping floors as beautiful as the day they were installed isn’t easy—but it is definitely worth the effort.

If your customers know proper care of their wood floors, their floors can last a very long time.

Things like regular cleaning, removing shoes, and clipping a pet’s nails can help increase the floor’s lifespan. And it’s always a good idea to remind your customers of the simple practices they can implement so they can keep their floors beautiful for years to come.

Bottom Line?

There are plenty of challenges to installing and owning hardwood floors. However, the most common and damaging culprit is moisture.

Stay in control of moisture by acclimating your floors, making sure your subfloor is dry, and regularly testing the MC of the hardwood with an accurate, non-damaging pinless meter.

Previously published in Tomorrow’s Contract Floors