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What Humidity Means For Your Wood Gymnasium Floor

What Humidity Means For Your Wood Gymnasium Floor

Wood floors are commonly used in gymnasiums because of their durability and natural aesthetic.  They are also the preferred flooring for several sports such as volleyball and basketball.  However, as the winter months count down and we move closer to the spring and summer, the increase in humidity can affect your wood gym floor.

wood gym floor

Wood is a hygroscopic material which means that it absorbs and releases moisture.  This causes the individual wood boards of a gym floor to expand and contract.  During the winter months, the low humidity levels cause the wood to contract, leading to visible gaps between the floorboards.  The higher humidity levels in the spring and summer cause the wood to expand, leading to tighter seams between the floorboards.  It is extremely important to maintain the appropriate humidity levels within your gymnasium to avoid excessive expansion and potential crowning of your wood gym floor.

In this guide, we will discuss how humidity affects wood gym flooring and what you can do to control the humidity levels in your gym or facility to protect the floor.

How Humidity Affects Wood Gym Flooring

Wood is a porous material which means it will always react to changes in humidity levels.  Higher humidity levels cause wood gym flooring to expand as it absorbs water and drier conditions cause the wood floor to contract by releasing moisture.  For the most part, the changes are small enough to go unnoticed and wood gym floors are typically installed to account for the inevitable expansion and contraction caused by minor changes in humidity.  However, large changes and inconsistent humidity can cause problems with the wood floor.

The best way to avoid issues with a wood gym floor is to keep the relative humidity level between 35 and 50 percent.  This is the recommended humidity level from manufacturers and installers of wood gym flooring as the humidity level can increase and decrease within this range without causing issues. When the humidity level gets above or below this range, problems with wood gym flooring are much more likely.

How Does High Humidity Affect Wood Gym Flooring?

Wood Gym Flooring from Kiefer USAWhen the relative humidity is too high, the wood gym floor will absorb excess moisture which leads to the following issues:

  • Cupping: Absorbing too much moisture can cause cupping in which the edges of the floorboards curve up towards the center, creating a “u” shape.
  • Crowning: Crowning is when the moisture absorption causes the center of the floorboards to rise above the edges and create a bubble under the wood.
  • Cracking: The floorboards expand as they absorb more moisture. The expanding floorboards push up against each other which can cause visible cracks in the wood.
  • Buckling: Buckling occurs when wood gym floors absorb enough moisture to expand beyond their current space, causing a gap between the gym floor and subfloor. Gym floors affected by buckling feel bouncy because of this space.

How Does Low Humidity Affect Wood Gym Flooring?

When the humidity level is too low, moisture within the wood is released, leading to the following issues:

  • Splitting: Wood gym floors must hold a certain level of moisture to be in the best shape. When the wooden floorboards become dried out, the wood can split, damaging the finish, and leaving the wood unprotected.  When the floorboards of a wood gym floor split, they need to be replaced.
  • Gapping: When wood floorboards release moisture, they shrink which creates gaps between the boards. If the floorboards shrink too much, they may not be able to expand again and will need to be replaced.

How to Control Relative Humidity Level

It is important to maintain the proper humidity levels in your gymnasium or facility to keep the wood gym floor in the best possible condition.  The easiest way to track the humidity level is to install hygrometers that can give you a reading of the relative humidity and temperature in real time.  It helps to have multiple hygrometers installed in different locations to get a complete picture of the humidity levels throughout the facility.

You should pay attention to the humidity levels in the gymnasium, especially during dry and humid seasons.  If the humidity levels are too high or too low, there are steps you can take to get the humidity back to the recommended range.

How to Lower the Humidity Level in the Gym

Wood Gym Flooring from Kiefer USAIf the humidity level gets too high, it can cause the problems described above, including cupping, crowning, cracking, and buckling.  The following tips can help you lower the humidity level in your gym if it rises above 50 percent:

  • Use dehumidifiers: Dehumidifiers help lower humidity levels by extracting the moisture from the air. Gyms in humid climates should invest in industrial dehumidifiers that can work with the HVAC system to dehumidify the gym when the humidity level reaches a certain point.  For gyms in dryer climates, portable dehumidifiers can help control the moisture level.
  • Control the temperature: Keeping the temperature within a moderate range can also help keep the humidity under control. The optimal indoor temperature for a gym with wooden floors is between 65° and 75°F.  A good air conditioning system may be required to maintain these temperatures during the summer.
  • Clean and replace air filters: HVAC systems help maintain indoor temperature and humidity levels when they are working efficiently. One way to ensure the efficiency of the HVAC system in the gym is to regularly clean or replace the air filters.  Clean air filters not only help the HVAC system better regulate the humidity, but also prevent dust and debris from falling on the gym floor and making the surface slippery.

How to Increase Humidity Level in the Gym

While this may not happen often, it is important to prevent the humidity levels from dropping too low in the gym.  Excessive dryness can cause the wood gym floor to split and gap which generally requires replacement.  If your gym is in a dry climate, you should consider installing humidifiers.

Industrial humidifiers can be incorporated into the HVAC system and blow humified air into the gym.  These are ideal for gyms in climates where dryness is a concern.  For areas that experience lower levels of dryness, portable humidifiers may be enough to keep the humidity within the appropriate range.

Wood Gym Flooring from Kiefer USA

Basketball Purdue Hardwood FlooringHardwood gym flooring gives gymnasiums and facilities a classic aesthetic and they can last a long time with effective care.  A major part of caring for wood gym flooring is maintaining the proper humidity levels to prevent damage to the floor.  By keeping the relative humidity levels in your gym between 35% and 50%, you can ensure that your wood gym flooring lasts for many years.

Kiefer USA is a premier installer of hardwood gym flooring for professional leagues, facilities, and schools at the elementary, high school, and collegiate levels.  Our experts help you through the entire process, from the design of your floor to the installation, to ensure that your wood gym flooring meets your exact specifications.  You can expect expert installation and we can incorporate team colors and logos into the design of the floor to give it a personal touch.

We have installed hardwood gym flooring for prestigious institutions such as the University of Kentucky, Purdue University, and the University of Notre Dame.  You can call us at (800) 322-5448 to learn more.



Amber Stromberg

Kiefer USA is a leading athletic surface design and sports flooring installation company. Amber Stromberg is a Director of Marketing. 10 Years with Kiefer.
Favorite Hobby: working out and spending time with her kids and family.

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