Posted on: 19.08.2022 Posted by: Редакция Comments: 0

Although it is undeniable how beautiful hardwood floors can be, unfortunately, they can also be sensitive to heat and moisture. Improper care can lead to excessive temperature changes and moisture exposure, causing cupping in certain areas. The good news is that it is possible to fix the problem and reverse the damage if it is addressed quickly.

To dry cupped hardwood floors, start by absorbing any visible water and running industrial fans in the room. Once the area starts to dry, introduce a dehumidifier to remove excess moisture trapped in the wood’s pores. Finally, use a moisture meter to check if the area is completely dry.

In this article, we will discuss what cupping is and how it can occur in your home. We will then explore how to properly dry your floors before potentially sanding and refinishing to level out the edges. When the edges curl up, the center of the board has a concave surface, bending inward instead of sitting flat. With the sides of the wood boards now sitting higher than the center, the floor becomes a tripping hazard.

Cupping occurs when the underside of the hardwood is exposed to moisture. Cupping is usually a sign of a water leak from pipes or even appliances like a refrigerator. Where the finish protects the top of the wood, moisture seeps into the unprotected parts that you cannot see.

Another common reason hardwood floors start to cup is that they were installed in the warmer months before the air conditioning was installed. When building or renovating a house, the flooring should be one of the last things installed. However, many construction companies lay the floors first because it is easier before fixtures or cladding have been added.

Unfortunately, this often results in the floors being laid before the heating and cooling systems are in place. Once these systems are installed, they are usually run to ensure they are functional. This leads to significant temperature changes that need to be taken into account before installing hardwood.

How to Dry Cupped Hardwood Floors

The first step in fixing your hardwood floors is to dry them thoroughly. After fully drying, you should be able to sand and refinish the affected area. In more severe cases, you may need to remove and replace some parts of the floor that are too damaged to repair.

Start by identifying the source of moisture and fixing any leaks in pipes or appliances. This can range from burst drain pipes to refrigerator leaks or a dishwasher overflow. If you are unsure where the moisture is coming from, it is recommended to hire a professional to locate the cause and address the problem before it gets out of control.

Before starting the drying process, always remove any furniture or carpets from the room. These can trap moisture and hinder the drying process. Make sure these are completely dry before placing them back in the room.


As mentioned above, cupping can occur when the hardwood is exposed to hot, humid temperatures in the summer and then cooler winter temperatures. This causes the wood to expand and contract, allowing moisture to seep into the gaps between the boards.

A dehumidifier is an excellent way to control the humidity levels in your home. If the moisture damage is minimal and the cupping is minor, a dehumidifier may be sufficient to address the problem. While removing moisture from the air, keep the doors and windows of the affected room closed and, if possible, run the air conditioning to prevent excessive moisture from entering during the warmer months.

As the wood expands in the summer, moisture can penetrate the wood grain, settling and not easily coming out. With a dehumidifier, this moisture should dry out when it runs long enough. For larger areas, rent an industrial-sized dehumidifier and let it run for at least 24 hours.


Industrial fans can also be rented from hardware stores or specialty shops. These fans are very powerful and can aid in the drying process, especially when used in conjunction with a dehumidifier. However, these types of fans are great for drying out a room with extensive water damage and should initially be used alone to remove as much moisture from the room as possible.

Set up the fans and let them run at full speed with windows open to allow for proper airflow. Once the area is sufficiently dried, bring in the dehumidifier and run it concurrently to ensure the hardwood is as dry as possible.

Wet/Dry Vacuum

If the moisture in your hardwood is the result of a leak or accident, such as a spilled mop bucket or dishwasher overflow, it is best to ensure the wood is as dry as possible with a wet/dry vacuum. This specialized vacuum is designed to suck up standing water.

Thoroughly go over the area, and once you have removed the visible water, wipe it dry with a cloth. Once the surface appears dry, proceed to vacuum and move slowly across the boards to remove moisture from the wood pores that will continue to cause damage down the line.

Moisture Meter Testing

A moisture meter is a tool used to determine the moisture content in building materials. If you suspect you have a leak, you can use such a device to check the moisture level of your floors to potentially locate the affected area.

After drying the floors with fans and dehumidifiers, use the moisture meter to ensure no moisture stains remain in the wood pores. If the meter shows positive, continue running the fans and dehumidifier for at least another day.

Sanding and Refinishing Hardwood Floors

In some cases, the damage to your hardwood is too severe to be fixed by simply drying the floors. If you still see depressions on the edges of some boards after thoroughly drying the floors, you will likely need to sand and refinish the area.

Sanding should be done by a professional or an industrial floor sander. This machine moves slowly across the hardwood, bringing it back to its normal state. Once the floor is leveled, make sure to treat it with sealant and stain as necessary.

Preventing Cupping on Hardwood Floors

When installing hardwood floors, it is best to have the heating and cooling systems running for a few weeks. This way, the house has a chance to adjust and acclimatize, preventing the hardwood from absorbing excessive moisture. During such times, try to keep the air conditioning running to keep your home cool and ensure all heat recovery ventilators are turned off. This prevents the unit from drawing in moist air from outside.

Lastly, always remove any spills on hardwood immediately and never mop with excessive water. The amount of water contained in mops will seep into the space between the boards and begin to accumulate under the hardwood. Over time, this will cause the edges to warp.

Moisture Testing Before Installing Hardwood Floors

While it is commonly assumed that most moisture issues are due to broken pipes or leaks, it is not uncommon for moisture to affect your flooring from the subfloor. Flooring consists of several layers, including:

  • Joists, which are the foundation for everything that comes above. Unless the floor is concrete, it will have joists made of laminated wood or wooden beams.
  • The subfloor is the next layer, providing a stable surface on which the underlayment and topmost layer sit. This layer facilitates the installation of the flooring and increases walking comfort.
  • The underlayment sits directly beneath the surface, providing insulation and support. For carpets, an underlayment can be thicker to provide additional cushioning and also helps prevent moisture from affecting the topmost layer.
  • The topmost surface is what you see as the finished result. This can be hardwood, laminate, or carpeting and is purely aesthetic, providing no structural support.

If any of the layers beneath the surface have high moisture content when installing the topmost layer, you may find that this leads to water damage. While it will take some time, the moisture will seep to the surface, causing your hardwood to warp or cup.

Additionally, leaving the subfloor or joists with high moisture can cause them to deteriorate over time. This can result in weakness and rot, eventually leading to a collapse of the floor. Always make sure the floor is completely dry before installing the next layer.

Final Thoughts

While hardwood floors may be beautiful, it is important to remember that they require more care than tiles or carpet. Even though a splash on the floor may seem insignificant, it can quickly penetrate the pores and cause depressions and warping within the wood.

If you notice depressions in your hardwood, start by identifying the source of moisture and fixing issues such as cracked pipes. Once the underlying problem is addressed, thoroughly dry the area with industrial-grade tools and sand down any remaining raised areas.

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