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Cupping, crowning, buckling, and peaking are used to describe warping and damage caused to both wood floors and engineered hardwood floors due to moisture or changes in humidity. It’s essential to keep these changes in mind during installation.


When excess moisture saturates the underside of your floorboards, a typical result is cupping. The sides of the boards will become higher than the center of the boards. This gives each floorboard a concave (or cupped) shape.

You can see the effect of this by placing a few drops of water on a countertop. Set a piece of paper on top of the water. Notice how the area that has contacted the water forms a concave bowl-like shape. This is what happens when your floorboards become wet from underneath.

The Cause

If the cupping happens rapidly, over a few days, the cause is likely a leak somewhere. Repair the leak and then call a professional to assess the problem and fix it. Hopefully, it will only need to be repaired rather than completely replaced.  

Floorboards can also cup and warp due to the humidity in the air. It can take up to a year or more to become evident, but changes will occur unless your home has a relative humidity level of zero or less. Usually, these changes are compensated for during installation, so no damage occurs with the boards’ natural shifting. Unfortunately, it can become a problem if the installation wasn’t done correctly.


Crowning is the opposite of cupping. Instead of the edges being higher than the board’s centerline, the centerline is raised like a little hill, and the edges are lower. One of the ways this can happen is after improperly repairing cupping. If the cupped boards are not thoroughly dried and then are sanded flat. Once the boards dry over time, the sanded areas will shrink, leaving a higher center and lower edges.


Buckling is yet another example of the damage that moisture can do to your wood floors. Buckling is when you notice the floorboard pulling away from the sub-floor. It can happen as a result of flooding, leaks, or humidity. But, water isn’t the only cause of buckling.

Buckling can happen if you don’t acclimate your floorboards to the climate in your home. The moisture content in your home’s air is different from that in the store or in the warehouse where the boards are stored. It’s important to allow time for the boards to acclimate to your home’s temperature and humidity level before installation.

Another cause of buckling is poor installation. The installers must give the wood extra room to expand and contract throughout the year with fluctuating temperature and humidity levels. If they don’t provide the floorboards with this space, the boards will buckle.

Improper Cleaning

Improper cleaning is another cause of buckling. Never use soap and water on your hardwood or engineered hardwood floors. Instead, use a cleaner that is meant for wood flooring, along with a microfiber mop.


Peaking occurs the same way that buckling does, except that improper installation is the most common culprit. Often the boards have not been given enough room to expand, and when they do, they end up heaving upward.

Dave’s Floor Sanding and Installation has been serving the Twin Cities metro area for over 40 years. You can count on us to repair or replace your flooring correctly. If you are having issues with cupping, crowning, buckling, or peaking, contact us today!