Last Updated: February 26, 2024
Hardwood is an elegant, durable, and practical flooring option for many interior applications. Hardwood floors are used in offices to create an elegant and sophisticated atmosphere, while homeowners use them to create beautiful, smooth, easy-to-clean surfaces.
Appropriately maintained hardwood floors can last for generations but are sensitive to extreme climatic conditions such as sweltering summers and frigid winters. Along with temperature changes, changes in living conditions and humidity levels can also affect your beautiful hardwood floor. Both high and low humidity are harmful to wood. According to the National Wood Flooring Association (NFWA), 90% of wood flooring failures relate to relative humidity and moisture problems in the home.
Maintaining a consistent, ideal humidity level is essential for keeping your hardwood floor looking great and for a healthy home environment. Wood is hygroscopic, meaning that it gains or loses moisture until it reaches an equilibrium with its surroundings. Hardwood floors are derived from living trees. Once a tree has been cut, the lumber is kiln-dried to remove moisture content before it is converted into hardwood flooring and various wood products. Although the lumber is separated from the tree, the cell structure remains the same, with the ability to absorb and release moisture. Wood dimensions expand or contract depending on how the wood absorbs or releases moisture based on its environment. When the expansion rate or contraction changes too drastically, wood flooring will display tell-tale, potentially worrisome signs.
How Humidity Affects Your Wood Floors
Once the temperature drops in winter, people turn on furnaces, fireplaces, and other heat sources to heat homes. The heat that keeps us warm dries the air out, lowering the humidity, leading the wood flooring to lose moisture and contract due to the dry, heated air.
Gapping: If the relative humidity in your home moisture is below 30%, the moisture content in the wood floor begins to evaporate. Excessively dry wood floors will shrink, and gaps will appear between the boards. Dry floorboards may splinter or split along the grain. Having gaps between your wood planks is normal. Once relative humidity returns to the average level, the hardwood floor will expand, closing most gaps.
Splits & Checks: When your home is very dry or humid, it can stress wood beyond its limitations. As the wood dries out, it increases the likelihood of split, check, cracking at the end of the wood planks and/or at the center, along the grain, damaging the finish. This can cause splinters to stick out that may hurt people or pets in the house. This damage is permanent as your hardwood floor finish is cracked. The problem worsens with time, as the finish no longer protects the wood flooring; moisture and debris can seep inside the wood and lead to more deterioration. Installing a whole-house humidifier that can be combined with the furnace or buying a portable humidifier and placing it into the room with hardwood flooring will help keep your flooring from developing gaps between the planks. Maintaining the optimal humidity level stable in this range will help avoid dimensional change and movement in the hardwood flooring. Installing a humidifier can also help your house plants enjoy higher moisture levels in the air as they brave through the dry winter months with the heat blasting.
During summers, humidity levels increases. As the humidity rises above 50%, wood floors begin to absorb moisture. The more humid the environment, the more moisture the wood absorbs and the more it expands. As the wood gets larger, the spaces between the planks shrink. In extremely high humidity and an inadequate expansion at the outer perimeter, wood floorboards can cup, crown, or even twist from the increased pressure brought about by water absorption. Even if the humidity levels return to normal levels, it can take some time for the wood to shrink back and regain its flat contour.
You can fix some of these problems by adjusting the humidity levels in your home. In the long run, the repeated changing of humidity levels can cause severe problems with your floors that may not resolve until you replace the damaged hardwood. Keeping your home’s humidity stable year-round is the best way to prevent humidity-related damage to your hardwood floors. It is important to note that the hardwood floor warranty does not cover the damage caused by humidity variations. Hence it is imperative to take proper care before it becomes expensive.
To keep the expansion of your floorboards to a minimum, it’s essential to keep the humidity level in your home below 50% during the summer months. Air conditioning naturally removes some humidity from the air. However, if you have wooden flooring installed in naturally humid areas, such as a basement, you may need to buy a dehumidifier for your hardwood floor to remove excess moisture.
Ideal Humidity Level for Hardwood Floors
Keeping the humidity and temperature at the recommended level is essential for keeping your hardwood floor looking great and providing you with a healthy home environment. While the optimal moisture for interior conditions can change for different types of wood, seasons, and climates, it’s ideal for keeping humidity somewhere in the 40 to 60% range to minimize contraction and expansion. As per the NFWA, the average relative humidity levels should range between 30%-50% to ensure the successful long-term performance of your wood flooring. However, this range can often be challenging to achieve in certain country areas during certain seasons.
If your home is consistently above the ideal humidity levels, it may lead to condensation that can harm your hardwood flooring. High humidity can also negatively impact your health as it may lead to mold and mildew growth and lead to viruses, dust mites, and bacteria thriving. Avoiding extremely dry air improves health, keeps skin from drying out, and limits the spread of airborne viruses.
How to Take Proper Care of Your Hardwood Floors
It is essential to take protective measures for your wooden floors to prolong their life. Wood is an incredibly popular building material, yet it is sensitive to environmental factors like humidity. With proper care, you can protect your laminate or hardwood flooring from buckling, cracking, and otherwise reacting to moisture and seasonal humidity. Try to follow these guidelines to prevent moisture problems on your floors:
Regulating your home’s humidity is the best way to keep moisture content levels at an ideal level. Installing a humidifier or a dehumidifier along with your heating system can help you maintain the right level.
While most modern-day appliances are equipped with a hygrometer, if yours is not, purchase it separately. This will allow you to monitor and adjust the humidity level in your home, similar to a thermostat.
Avoid using water or water-based cleaning products to clean your wood floors regularly, especially after sanding.
Carefully sweep or vacuum hardwood flooring and use a new finish or cleaning product made for the purpose.
Never mop on a wood floor, and do not let spilled water remain pooled on the floor as it can cause lasting damage to the boards. Wipe it up with rags or paper towels right away.
Instead of mopping, clean your floors with a cloth lightly dampened with a cleaning product recommended explicitly for wood or laminate.
Maintain proper humidity levels with an air conditioner, dehumidifier, or by turning on your heating system periodically during the summer months.
Do not use vinegar to clean your floor. Vinegar is acidic; prolonged exposure to it will break down the finish on the surface of your hardwood floor and will reduce the shine, and leave a dull appearance.
Undergo professional hardwood floor deep cleaning every 1-2 years. Apply maintenance coats or polish may be applied as needed on high traffic floors.
When running around on hardwood floors, indoor pets can cause expensive damage over time. A softer variety of woods is prone to gauge and scratch. Even the most durable floor finishes will not prevent this from happening. Hence keep their nails trimmed.
If you have indoor plants on your wood flooring, it is ideal for keeping plastic trays under them. Constant excessive moisture from the moist plant-soil may lead to hardwood flooring expansion and discoloration in that area.
Choose a hardwood flooring cleaning kit, and keep the water usage minimal. Always immediately clean up any water spills.
When you use wood stoves or electric heat, ensure to keep your humidifier on as they tend to create very dry conditions.
If you are a “snowbird” or travel frequently for a long time, make sure always to keep the temperature and relative humidity at the recommended level.