Hardwood floors are prized for their warmth and long-lasting beauty. But even the most durable wood floor isn’t immune to one of its oldest enemies: humidity. As a natural material, wood responds to changes in moisture in the air—and if those changes are too extreme, your flooring can suffer in ways that are both unsightly and costly to fix.
If you notice changes in your wood floors, reach out to a hardwood flooring pro for tips and assistance.
But first, understanding how humidity affects hardwood and what you can do to protect your floors will help you maintain their appearance and integrity for years to come. Here’s what you need to know:
Why Wood Reacts to Humidity
Wood is hygroscopic, meaning it naturally absorbs and releases moisture based on the surrounding environment. When humidity levels rise, wood draws in moisture and expands. When humidity drops, it releases moisture and contracts.
This process is completely normal. In fact, it’s expected and accounted for during installation. But when humidity levels swing too far in either direction—or change too quickly—your floors may begin to show signs of stress.
What Happens When Humidity Gets Too High
Excessive humidity can lead to:
1. Cupping
Cupping happens when the edges of a wood plank rise higher than the center, creating a slight bowl shape. This happens when the underside of the plank absorbs more moisture than the top.
2. Swelling and Warping
When wood expands causing boards to lift or distort. This pressure causes buckling, where planks actually lift off the subfloor.
3. Mildew or Mold
High humidity can contribute to mold growth beneath or around your flooring. Even if it’s not visible, it can affect indoor air quality and damage the structure over time.
What Happens When Humidity Drops Too Low
On the other end of the spectrum, low humidity—especially during dry winter months—can cause:
1. Gapping
As moisture leaves the wood, the planks shrink and leave gaps between each board. These gaps may be temporary and close up in spring, but if the humidity drop is too extreme or too frequent, the gaps can become permanent.
2. Cracking or Splitting
Boards can crack due to repeated expansion and contraction. This impacts the appearance of your floor and its long-term stability.
Ideal Humidity Range for Hardwood Floors
Aim to maintain indoor humidity levels between 35% and 55% year-round. This range gives the wood enough moisture to remain stable without risking expansion or shrinkage.
How to Prevent Humidity Damage
Protecting your wood floors from humidity isn’t difficult, but it does require being proactive.
1. Use a Hygrometer
This small, inexpensive device measures the humidity in your home. Keep one in rooms with wood flooring to monitor conditions throughout the year.
2. Install a Humidifier or Dehumidifier
● In winter, when indoor air becomes dry from heating systems, use a humidifier to maintain moisture levels.
● In summer, especially in humid climates or basement levels, consider a dehumidifier to reduce excess moisture in the air.
Whole-house systems tied to your HVAC are ideal, but portable units can work well for single-room adjustments.
3. Maintain Consistent Temperatures
Sudden changes in temperature can affect humidity. Avoid wide fluctuations in indoor heating and cooling settings, especially when you’re away from home for extended periods.
4. Control Moisture at the Source
If your floors are installed over concrete or near plumbing, make sure vapor barriers are in place and that leaks are promptly addressed. Kitchens, bathrooms, and laundry areas need special care to prevent prolonged moisture exposure.
5. Let New Wood Acclimate
Before installation, wood flooring should acclimate to your home’s environment for several days. This step allows the wood to adjust to the temperature and humidity of your space, reducing the chance of future movement.
Hardwood Flooring Done Right for Over 80 Years
At Cameron the Sandman, we specialize in restoring and protecting hardwood floors in homes throughout Michigan. We’re here to provide expert advice or a complete flooring refresh. Give us to have our team help you maintain your floors’ appearance.