If you’ve ever installed laminate flooring—or even just admired it—you might have noticed something frustrating: sometimes, the planks swell, warp, or start to buckle seemingly out of nowhere. I’ve seen homeowners pull their hair out when the floor that looked perfect on installation day suddenly turns into a wavy mess within weeks. Trust me, I’ve been there too.
Understanding why laminate flooring expands isn’t just a curiosity—it’s essential for keeping your floors looking sharp and lasting for years. Laminate reacts to humidity, temperature changes, and moisture in the subfloor, and ignoring these factors is like building a sandcastle too close to the tide. One wrong move and your hard work can go up in smoke.
In this guide, I’ll walk you through everything I’ve learned on the job: what causes laminate to expand, how to spot the warning signs, common mistakes DIYers make, and practical solutions to keep your floor flat, stable, and beautiful. Along the way, I’ll share first-hand tips, real-world examples, and actionable advice so you don’t have to learn the hard way like I did. By the end, you’ll know exactly how to prevent swelling, protect your investment, and keep your laminate floors looking like new.
Key topics we’ll cover:
- The materials that make up laminate flooring and how they react to moisture
- How temperature swings can cause planks to move
- Signs your laminate is expanding
- Common causes of excessive expansion
- DIY solutions and repair tips
Think of this as your roadmap to keeping your laminate flooring smooth, stable, and stress-free—even if you’re a first-time DIYer.
How Temperature Affects Laminate Expansion
Laminate flooring doesn’t just react to moisture—it’s sensitive to temperature changes as well. Hot summers, cold winters, or even the afternoon sun streaming through your windows can cause planks to expand and contract. Understanding how temperature interacts with your flooring is key for DIYers and homeowners who want their floors to stay flat and smooth over time. In this section, I’ll break down how heat affects laminate and what you can do to minimize movement before it becomes a problem.
Heat Causes Plank Movement
One thing I’ve learned over years of installing laminate is that heat can be just as sneaky as moisture. Laminate flooring expands and contracts with temperature changes, and if you’re not prepared, those planks can start shifting right under your feet. For example, a sun-soaked living room in the afternoon can cause the flooring to expand, while cooler nights make it contract.
I remember installing a floor in a San Diego home where the client’s living room faced west. By the end of the day, the floor had already started pushing against the baseboards. The culprit? Direct sunlight combined with a warm indoor temperature—simple physics, but enough to make a DIY job go sideways.
Tip for homeowners: Avoid installing laminate in extreme temperatures. If it’s hot outside, let the air conditioning run for a day before you start. Conversely, in cold climates, give the room a chance to warm up. That little adjustment can save you from costly repairs later.
Sunlight and Room Location
The room where you install laminate matters more than most people realize. Planks near windows or doors exposed to sunlight expand faster than those in shaded areas. Over time, this uneven expansion can lead to gaps, buckling, or even warped edges.
A quick fix I often recommend is using UV-resistant blinds or curtains, especially in rooms with large windows. Not only do they reduce sunlight-driven expansion, but they also protect the floor’s surface from fading—a two-birds-one-stone situation.
Pro Tip: When planning your installation, take note of the orientation of the room and windows. If you anticipate heavy sun exposure, leave slightly wider expansion gaps. It’s a small step that pays big dividends down the line.
The Science of Laminate Expansion
Before you can prevent laminate from buckling or warping, it helps to understand the science behind why it moves. Most laminate floors are made with wood-based cores that naturally expand and contract in response to changes in moisture and temperature. Knowing how your flooring reacts, and why expansion gaps are essential, will help you avoid surprises and DIY mistakes. In this section, I’ll dive into the science, explain what makes laminate expand, and share practical tips from my years of installation experience.
Hygroscopic Nature of Wood-Based Core
Here’s where things get interesting: the core of most laminate flooring is made from high-density fiberboard (HDF), which is essentially compressed wood fibers. Wood is hygroscopic, meaning it naturally absorbs and releases moisture from the surrounding environment. This is why your laminate can expand during humid summer days and shrink during dry winter months.
I’ve seen it happen countless times—newly installed planks looking perfect one week, then starting to buckle slightly the next. The homeowners were puzzled, but once we measured the humidity and checked the subfloor, it was a no-brainer. The HDF core was simply reacting to moisture in the air, doing exactly what nature intended.
DIY Tip: Keep indoor humidity levels between 35% and 65%. A simple humidifier or dehumidifier can make a world of difference in controlling seasonal expansion.
Expansion Gaps Are Non-Negotiable
If there’s one lesson I’ve learned installing floors across countless homes, it’s this: skipping expansion gaps is asking for trouble. Laminate needs space to expand and contract, and those gaps act as a safety valve. Without them, planks push against each other, baseboards, or walls—and that’s when you see buckling or warping.
Standard practice is to leave around 1/4” to 1/2” of space at all edges and around doorways. I once had a client insist on a “tight fit” for aesthetics, and within weeks, the floor started to lift at the seams. Lesson learned: sometimes beauty needs a little breathing room.
Pro Tip for DIYers: Use spacers during installation to maintain consistent expansion gaps. Don’t eyeball it; even a small miscalculation can turn into a bigger headache down the road.
Signs Your Laminate Flooring Is Expanding
Laminate flooring doesn’t usually shout when it’s having problems—it gives subtle warnings first. Knowing what to look for can save DIYers and homeowners from costly repairs and frustration. From visible warping to unusual noises, the signs are often right under your nose if you know where to check. In this section, I’ll walk you through the most common indicators that your laminate is expanding and what you can do before the damage escalates.
Visible Buckling or Warping
One of the first signs I always tell homeowners to look out for is visible buckling or warping along the edges or between planks. If a section of your floor looks like it’s rising or forming a small ridge, that’s your laminate crying for help.
I remember visiting a home where the laminate near the patio doors had started to curl upward. A quick check revealed that the homeowners had neglected proper expansion gaps, and the planks were swelling due to the humid air from outside. Catching these early signs is critical—once the buckling worsens, you may have to remove and replace entire sections.
Tip: Regularly inspect your laminate, especially in areas prone to humidity like kitchens, bathrooms, and sun-facing rooms. A little preventive check goes a long way.
Clicking or Popping Sounds
Another subtle but telling indicator is clicking or popping sounds when you walk across the floor. This happens when the laminate expands and the planks rub against each other or the subfloor. Many homeowners ignore the noise until it becomes a visible problem.
I’ve had clients call me about “noisy floors” only to discover that the planks were tight against walls and furniture, causing minor buckling. Fixing the gap or relocating furniture slightly often resolves the issue without major repairs.
DIY Tip: If your floor starts making unusual sounds, check the edges and expansion gaps immediately. Addressing it early can save you a ton of headache—and money.
What Laminate Flooring Is Made Of
Before you can tackle expansion problems, it’s important to understand what laminate flooring is made of. Most DIYers don’t realize that beneath the stylish wood-look surface lies a high-density fiberboard (HDF) core that behaves much like natural wood. The materials, layers, and construction all play a role in how your floor reacts to moisture, temperature, and wear over time. In this section, I’ll break down the composition of laminate, explain how each layer reacts to environmental changes, and share practical tips to minimize problems before they start.
Core Materials Matter
When I first started installing laminate floors, I quickly realized that not all planks are created equal. At its heart, laminate flooring is made of high-density fiberboard (HDF), topped with a decorative layer and sealed with a melamine overlay. The HDF core gives the plank its strength, while the decorative layer mimics real wood, stone, or tile.
Here’s the kicker: that HDF core is wood-based, which means it reacts to moisture and temperature just like natural wood. That’s why understanding the materials is the first step in preventing your floors from suddenly expanding like a balloon in a sauna. If you ignore the core’s properties, even the best-looking laminate can turn into a headache.
Role of Moisture in Laminate
One of the most common mistakes I see DIYers make is underestimating moisture. The wood fibers in the HDF core are hygroscopic—they absorb water from the air and release it when the air dries. In practical terms, this means your laminate will expand on humid days and shrink during dry seasons.
I once installed a laminate floor in a kitchen without checking the subfloor moisture. Within a week, the edges started lifting, and the planks were buckling near the sink. Lesson learned: even small amounts of water or high humidity can wreak havoc. Using moisture-resistant underlayment and keeping an eye on indoor humidity can save you a lot of grief down the line.
Tip for DIYers: Always store your planks in the room where they’ll be installed for at least 48–72 hours. This acclimation period lets the planks adjust to the local temperature and humidity, which dramatically reduces the chance of unwanted expansion.
Common Causes of Excessive Expansion
Even the best-installed laminate floors can run into trouble if certain conditions aren’t controlled. Over the years, I’ve noticed that most cases of excessive expansion fall into a few predictable categories. Knowing these causes can help DIYers and homeowners take preventive action before your floor starts buckling or lifting. In this section, I’ll walk you through the most common culprits and share practical solutions that actually work in the real world.
High Indoor Humidity
One of the biggest offenders is high humidity inside the home. Kitchens, bathrooms, and basements are particularly prone to moisture, which causes the HDF core to absorb water and swell. I remember a client whose laminate near the bathroom door had started curling upward after a week of heavy rains—simply because the room’s humidity was consistently above 65%.
DIY Tip: Maintain indoor humidity between 35–65%. Use a dehumidifier in damp areas and consider placing moisture barriers under the laminate in particularly humid rooms. It’s like giving your floor a pair of breathable shoes—it keeps everything snug but not suffocated.
Improper Acclimation Before Installation
Skipping or shortening the acclimation period is a mistake I see all the time with DIY installations. Laminate planks need 48–72 hours to adjust to the room’s temperature and humidity before being installed. Installing them straight out of the box can cause immediate expansion issues, as the planks will adjust once in place.
Pro Tip: Always check the manufacturer’s instructions and let your laminate “rest” in the room where it will be installed. Trust me, a little patience here saves you from pulling up planks later.
Subfloor Moisture Issues
Even if your indoor humidity is perfect, moisture from the subfloor can wreak havoc. Concrete slabs, water leaks, or uneven dampness under the flooring can lead to swelling and warping. I once inspected a living room where the subfloor had a minor leak—planks installed above started expanding, leaving noticeable gaps at the edges.
DIY Tip: Always test your subfloor for moisture before installation. Use a moisture meter if needed, and never install laminate on a wet or damp surface. A proper underlayment with a moisture barrier can also help prevent problems before they start.
DIY Solutions to Prevent Laminate Expansion
After years of installing floors, I can tell you that preventing laminate expansion is mostly about planning and consistent maintenance. There’s no magic trick—just smart preparation, attention to your environment, and following a few key rules. In this section, I’ll share the most effective DIY strategies to keep your laminate stable, flat, and looking brand-new for years.
Control Indoor Humidity
Humidity is the number one culprit behind swelling laminate. In my experience, the most successful DIYers are those who monitor and control their home’s humidity.
- Keep indoor humidity between 35–65%.
- Use a humidifier in winter if your air is too dry.
- Use a dehumidifier or air conditioning during summer or in humid climates.
I once helped a homeowner in a humid coastal area prevent buckling simply by running a dehumidifier in the living room. A small investment prevented a massive headache down the line.
Leave Proper Expansion Gaps
Expansion gaps are your laminate’s safety valve. I can’t stress this enough: never skip them. Without the proper spacing, planks push against each other and the walls, causing warping or buckling.
DIY Tip: Use spacers to leave 1/4” to 1/2” gaps around all walls, doors, and fixed objects. Check your manufacturer’s instructions, because some planks require slightly larger gaps depending on length and width.
Use Quality Underlayment
A good underlayment not only cushions the floor but also acts as a moisture barrier, reducing expansion risks. Over the years, I’ve seen cheap underlayments fail, allowing moisture to seep up from the subfloor.
- Invest in moisture-resistant or foam underlayment.
- Choose options with soundproofing or thermal insulation for added comfort.
- Always ensure the underlayment is flat and continuous, with seams properly taped.
Routine Maintenance Tips
Even a perfectly installed floor can run into problems if neglected. A few simple maintenance habits can save you from major repairs:
- Wipe up spills immediately to prevent moisture absorption.
- Avoid wet mopping—use a damp mop instead.
- Move heavy furniture carefully; consider felt pads or sliders.
- Check expansion gaps periodically to ensure they remain clear.
Pro Tip: Think of your laminate like a high-maintenance car—you don’t need to baby it constantly, but regular care keeps it running smoothly.
Repairing and Managing Expansion Problems
Even with the best preparation, sometimes laminate flooring still decides to push the envelope. From minor buckling to full-blown warping, the key is knowing how to act quickly before small issues turn into expensive repairs. In this section, I’ll share practical steps for fixing minor expansion problems, as well as guidance on when it’s time to call in a professional.
Fixing Minor Buckling
If your laminate is just starting to curl or lift at the edges, there’s often a simple solution.
- Remove the baseboards or molding along the affected area.
- Gently push the planks back into place.
- Place a heavy object on top for a day or two to help them settle.
I’ve done this countless times for homeowners who panicked when they saw the first signs of lifting. In most cases, the floor returns to normal without replacing a single plank.
Dealing with Moisture-Induced Swelling
When moisture is the culprit, you need to tackle both the floor and the source.
- Identify the leak or high-humidity area and fix it immediately.
- Use fans or a dehumidifier to dry the room thoroughly.
- In some cases, you may need to remove the affected planks temporarily until the subfloor is dry.
A client once had a small leak under a laminate floor near a kitchen sink. By acting fast—drying the subfloor and replacing just a few planks—we avoided a full replacement. Acting early is the name of the game.
When to Call a Professional
There are times when DIY fixes aren’t enough:
- Extensive buckling across multiple rooms
- Severe water damage from leaks or flooding
- Planks that cannot be reseated properly
In these situations, calling a professional is not a sign of weakness—it’s smart risk management. Professionals have the tools and experience to remove damaged planks, address subfloor moisture issues, and reinstall floors without further damage.
Pro Tip: Even if you’re a DIYer at heart, don’t hesitate to get expert help when the problem exceeds minor corrections. It can save you from headaches, wasted time, and extra costs down the line.
Final Thoughts
Laminate flooring can be a dream for DIYers and homeowners—durable, stylish, and surprisingly easy to install—but only if you understand why it expands and how to manage it. Over the years, I’ve learned that most expansion problems boil down to a few key factors: moisture, temperature changes, poor acclimation, and skipped expansion gaps. Recognizing the warning signs early and taking proactive steps can save you from headaches, costly repairs, and warped floors.
Key Takeaways:
- Acclimate your planks for 48–72 hours before installation to reduce initial expansion.
- Maintain proper expansion gaps around walls, doors, and fixed objects—never skimp on this step.
- Control humidity and temperature in your home to minimize seasonal swelling or shrinking.
- Inspect and maintain your floor regularly, especially in high-moisture areas.
- Act quickly at the first sign of buckling or popping sounds to prevent minor issues from becoming major problems.
In my years of installing floors across countless homes, I’ve seen what works and what doesn’t. With a little preparation, attention to detail, and timely maintenance, you can keep your laminate floors looking smooth, stable, and beautiful for years to come. Remember: a stitch in time saves nine—catch problems early, and your floor will thank you.
