Signs of Water Damage to Wood Floors

The absorbency of natural wood makes it susceptible to water damage, and wood flooring is no exception. While sealants and finishes are intended to protect wood flooring against water damage, improper installation or careless maintenance can leave flooring vulnerable.

Most water damage can be prevented by proper maintenance.

Rooms that involve plumbing fixtures, such as laundry rooms and kitchens are particularly prone to water damage as they are likely to have leaks.

Mold and mildew

Dark or discolored spots are an indication of mold or mildew, which is an obvious sign of water damage. If these spots are topical and haven’t penetrated through the sealed surface, it should be easy enough to simply clean it off. You may also need to reseal the area to ensure that continual build-up will not damage the floor. Find and eliminate the source of the mildew. If the room is susceptible to humidity, you may need to use Damp-Rid or some other moisture control method.


Cupping occurs when a dip appears in the center of a board with the edges raised around it, similar to the shape you make when cupping your hands. It is the result of a moisture imbalance in which the wood on the bottom of the board contains more moisture than the top. Spills left unattended can cause cupping but extreme humidity is usually the culprit. Once you have identified and eliminated the source of moisture, the board may return to normal after it has dried out, but it will most likely need to be sanded and refinished.


As opposed to cupping, crowning occurs when the center of the board bubbles up above the edges rather than dipping down. It is also the result of moisture imbalance, however, with crowning the top of the board has absorbed more moisture than the bottom. This is usually caused by leaky plumbing or condensation from appliances that are not functioning properly. Unattended spills can also contribute to crowning. As with other problems, locating and eliminating the source of the moisture is imperative. Once the area has completely dried you can better assess the damage and determine the necessary repairs.


Buckling is the rare occurrence in which the hardwood boards completely pull away from the subfloors. This is usually the result of extensive and long term flooding in the affected area. Flooring in which buckling occurs usually has to be completely replaced.