Hardwood floors are timeless. They bring warmth, elegance, and durability to any space. But over time, many homeowners notice something unsettling—gaps between the planks. These gaps may seem like a small issue, but they can become a source of frustration. They might change the look of the floor or even lead to potential long-term damage. So, what exactly causes these gaps, and more importantly, how can they be prevented? Let’s explore the science behind why hardwood floors shrink and expand, and what you can do to keep them looking flawless for years to come.
What Causes Gaps in Hardwood Floors?
The primary culprit behind gaps in hardwood floors is moisture. Wood is a natural material that responds to changes in humidity and temperature. When wood absorbs moisture, it expands; when it loses moisture, it contracts. This constant expansion and contraction are known as wood’s “moisture content equilibrium,” and it’s the foundation of why gaps appear in hardwood floors.
- Humidity and Temperature Fluctuations. As humidity levels rise and fall throughout the year, the wood in your floors expands and contracts. In warmer, more humid months, wood absorbs moisture from the air and swells. In colder, drier months, the moisture is released, causing the planks to shrink. This cyclical pattern is a natural behavior of wood, but it can lead to noticeable gaps if the fluctuation is significant. The most extreme changes tend to happen between winter and summer. In winter, homes tend to dry out due to heating systems, while in summer, humidity levels can rise, and the air is wetter.
- Improper Installation. If the wood isn’t acclimated to the room’s temperature and humidity before installation, it may not fit properly. Wood needs to adjust to the environmental conditions in the space where it will live. Without proper acclimation, the wood may shrink once it’s installed, leading to unsightly gaps between the planks.
- Subfloor Issues. The condition of the subfloor can also play a role in the formation of gaps. If the subfloor is not level, or if it’s too dry or too wet, it can affect the way the hardwood planks sit and expand. A subfloor that’s too moist can introduce excess water into the wood, causing it to swell and potentially buckle. Conversely, a dry subfloor can cause the wood to shrink as it loses moisture. Both extremes create imbalances that lead to gaps.
- Seasonal Shrinkage and Expansion of Wood. Wood is a living material, and like many other living materials, it responds to its environment. During the winter months, when indoor heating systems dry out the air, the moisture content in hardwood decreases, causing the wood to contract. This contraction is the primary cause of those frustrating gaps between planks.
In the summer, the air becomes more humid, and wood absorbs moisture, leading to expansion. In the absence of a tight seal between the planks, this expansion can cause the boards to cup or buckle. This seasonal back-and-forth movement can be expected in any hardwood floor. However, how much this impacts your floor depends on the wood species, the quality of installation, and how well the floor is maintained.
How to Prevent Gaps in Hardwood Floors
While it’s impossible to completely stop wood from responding to moisture changes, there are several measures you can take to minimize the risk of gaps and ensure the longevity of your hardwood floor. Let’s look at the best ways to prevent this common issue from turning into a headache.
- Maintain Consistent Humidity Levels. The most effective way to prevent gaps from forming in your hardwood floors is to control the humidity levels in your home. Installing a humidifier during the winter can add moisture to the air, preventing the wood from drying out too much. In the summer, using a dehumidifier can help reduce excess moisture in the air, preventing the wood from absorbing too much water. Ideally, the humidity in your home should be maintained between 35% and 55% year-round.
A whole-house humidifier or dehumidifier, which is integrated into your HVAC system, can be an especially effective way to maintain consistent humidity levels. For smaller rooms or areas that are more susceptible to moisture imbalances, portable units can also be a practical solution.
- Acclimate the Wood Before Installation. One of the best ways to prevent gaps from appearing in new hardwood floors is to ensure that the wood has been properly acclimated to the space before installation. Hardwood floors should be left in the room for 48 to 72 hours before they are installed, allowing them to adjust to the room’s temperature and humidity levels. This practice helps the wood reach an equilibrium, reducing the likelihood of shrinkage and expansion after installation.
- Ensure Proper Installation. Hiring a professional who understands the nuances of hardwood installation can make all the difference. A skilled installer will leave the appropriate expansion gaps around the edges of the floor to allow for natural wood movement. These gaps, typically covered by baseboards or molding, are critical to preventing buckling or gaps between planks.
In addition, if you’re considering floating hardwood floors, which don’t require nails or staples for installation, ensure that the subfloor is properly prepared. A floating floor allows for slight movement of the wood, preventing the planks from becoming too tight or too loose.
- Use High-Quality Hardwood. Choosing high-quality wood that is well-suited for the environment in which it will be installed is crucial. Hardwoods like oak, maple, and hickory are generally more stable than softer woods like pine or cherry, which tend to shrink and expand more noticeably with changes in humidity. The more durable the wood, the better it will handle the natural fluctuations of temperature and moisture. Also, consider opting for engineered hardwood, which consists of multiple layers of wood that are bonded together. Engineered hardwood is less susceptible to changes in temperature and humidity than solid hardwood, making it a more stable option for areas with fluctuating conditions.
- Practice Regular Maintenance and Cleaning. Maintaining your hardwood floor by keeping it clean and protected can also help prevent issues with gaps. Dust, dirt, and debris can settle into the spaces between planks, causing damage or allowing moisture to get trapped, leading to expansion or contraction. Regularly sweep, vacuum, or mop your hardwood floors to keep them free from particles that can disrupt their surface. Additionally, avoid using harsh chemicals or excessive water to clean your hardwood floors. Over-wetting the surface can damage the wood and cause it to swell, which, over time, can lead to gaps. A damp mop with a wood floor cleaner that’s appropriate for your floor type is the safest choice.
- Consider Professional Help for Repairs. If you notice existing gaps in your hardwood floors, addressing them early can prevent further damage. You can attempt wood floor gap fillers or consult a professional who can sand and re-stain the planks. In more severe cases, an experienced flooring professional may recommend re-finishing or replacing certain planks.
For floors with excessive moisture damage, it might be worth considering replacing sections of the wood that are more prone to expansion and contraction. This may involve re-acclimating the new wood to the space before installation.
Conclusion
Gaps in hardwood floors can be a natural and common occurrence, but with the right care and preventative steps, they don’t have to be a major issue. By maintaining stable humidity levels, acclimating wood properly before installation, and choosing high-quality materials, you can minimize the risk of gaps appearing in your floor. Keeping your hardwood floors clean, regularly checking for moisture imbalances, and ensuring proper installation will ensure that your floors maintain their beauty and functionality for many years to come.