7 Common Hardwood Flooring Problems and How To Prevent Them

A woodworker preparing boards for a hardwood floorRoger stepped back and sighed with a sense of accomplishment. His brand new white oak floor and kitchen cabinets glistened. The remodel was nearly complete.

Or so Roger thought.

Until he noticed something strange on the wooden floor near his fridge. Why were the sides of the floorboards turning upward?

His excitement vanished as he knelt down and ran his hand along the uneven flooring planks. Under the fridge, his hand hit a puddle of water.

More investigation revealed the culprit:

A steady leak from the ice maker line. Roger groaned. How could he have forgotten to tighten it when he had reinstalled the fridge a few days before?

Down in the basement, he discovered his greater fear:

Water had leaked through the floor.

What a headache! A long project had just become longer—all because of water damage.

Unfortunately, Roger’s situation is not rare. Water damage is one of the most common hardwood flooring problems. That’s why we’re here to help you avoid it as much as possible. So let’s discuss:

7 common hardwood flooring problems

Hardwood flooring is classy and beautiful, but not without challenges. Here, we’ll discuss seven of the most common problems.

They are:

  1. Dents and scratches
  2. Changes in color
  3. Gaps
  4. Squeaking
  5. Cupping
  6. Crowning
  7. Buckling

1. Dents and scratches

A cat sits on a wooden table with a hardwood floor in the backgroundDents and scratches are an inevitable part of owning a hardwood floor. They might come from a pet’s sharp claws or dropping a can of soup on the floor.

And as the floor gets older and the finish begins to wear off, dents and scratches will happen more easily.

Refinishing the entire floor can help prevent damage, but to deal with preexisting marks, you may have to sand the floor before adding a coat of finish.

2. Change in color

A hardwood floor can change color from sun exposure, pet urine, and spills. But the most common is when UV rays from the sun affect the finish on the wood floor, causing it to fade or darken—this is called oxidation.

You may not even notice it.

That is until you decide to move your rug or couch around. Surprise! Your floor has a couch-shaped spot that’s different from the rest of the floor.

What to do now?

The good news is that with some sun exposure, this part of the floor will eventually oxidize to match the rest of the floor.

But there are other options. (And you’ll have to resort to these options when it comes to stains from pets or spills.)

You could screen the floor, meaning that you sand the floor to remove the finish layer without removing any of the wood. Once this is done, add a new coat of finish. If the color change is more significant, sanding the wood and refinishing may be your next best choice.

3. Gaps

A wood floor with gaps between the boardsGaps between floorboards are another common occurrence in wood floors. In fact, some slight gaps are normal with the changing seasons as the wood contracts and expands.

Here’s what’s going on:

If the floor was installed during a humid time of year (summer), the change to a drier season (winter) can cause it to shrink as it loses moisture. This results in gaps.

The problem is when these gaps become large, ruining the appearance of your otherwise pristine floor. In this case, installing a humidifier and running it throughout the winter may help the wood to expand and may prevent large gaps from occurring again. Be sure to monitor the humidity levels in your home so that you don’t end up with too much moisture in the environment.

If you determine that the gaps in your floor are not related to a change in environment, you may consider putting wood filler into them. But be sure to do this in the summertime when the gaps will be the smallest. You don’t want to fill them during the winter, only to have the wood planks expand in the summer, causing more damage.

For large, unsightly gaps—particularly those in an old floor—replacing the floor might be your best option. After all, wood filler is subtle in minor gaps but much more obvious in large gaps. It will never look exactly like the original wood.

4. Squeaking

Hardwood floorboardsSqueaking can happen, even in new floors. It’s usually due to a change in the wood of the subfloor or joists (horizontal boards that support the subfloor and floor).

Possible culprits? Changes in climate, improper MC (moisture content) of the wood that was used, water damage, or improper installation (such as not enough nails, wrong kind of glue, weak or thin subfloors, etc.).

The warping or shifting of the wood can lead to the floorboards, subfloor, or joists touching each other in ways that cause squeaking.

To deal with it, first fix any moisture issues.

Once you’ve ruled out moisture, find ways to fill the spaces or gaps that are causing the squeakiness. If you can access the floor from underneath, fill any gaps or spaces between the joists and the subfloor with adhesive or wooden shims. Nailing a wood plank along the joists from underneath may also help.

If you can only access your floor from above, then try using a lubricant between the floor joints or nailing the floorboards into the joists. Use wood filler to cover the nails.

5. Cupping

Another type of moisture-related damage is cupping, which occurs when there is more moisture on the bottom of the floorboard than on the top. As a result, the sides of the board begin to lift up (lengthwise), creating a cup.

This problem can have a number of causes, such as:

  • A subfloor with excessive moisture
  • Moisture in a crawlspace or basement
  • Lack of a vapor barrier
  • Changes in climate
  • Waker leaks or spills

When fixing moisture-related damage to hardwood floors, deal with the source of the moisture, especially if it’s a leak of some sort. Then determine the EMC (equilibrium moisture content) for your area and use a moisture meter to figure out how close your flooring and subfloor are to that number.1

If the damage is minimal, a dehumidifier and better climate control can help the cupped floor to correct itself.

But substantial damage may require sanding and refinishing or replacing the affected boards.

6. Crowning

Crowning is the opposite of cupping. With this type of damage, there is more moisture on top of the board than on the bottom, causing the center of the board to swell and rise.

As with cupping, it’s important to identify and solve the moisture issue before trying to fix the appearance of the boards. If the problem was related to the climate, adding a dehumidifier may solve the problem.

But if not, you can sand and refinish the boards once they’ve dried sufficiently.

7. Buckling

Buckling is a more severe type of damage in which the floorboards begin to lift from the subfloor. It can result from flooding or major leaks that leave standing water on the floor.

It can also occur if the floor doesn’t have enough expansion joints to allow for some changes in moisture.

Once again, it’s important to fix the source of the leak. Then, you’ll probably need to take up the damaged boards and allow them to dry, also airing out the subfloor.

Only when your moisture meter indicates that the boards are at the correct moisture content should you put in the repaired boards or new boards.

The rest of Roger’s story

After Roger called in a professional to take a look at the damage to his floor, he learned that he was dealing with—you guessed it—cupping.

The solution?

He would have to remove the new cabinets, pull up the damaged flooring, and dry the subfloor before he could re-install the flooring and cabinets.

The wasted time and money were agonizing!

So how can you avoid an issue like Roger’s? Read on to find out!

3 steps to prevent hardwood flooring problems

When it comes to hardwood flooring problems, especially those related to moisture, the best thing you can do is prevent them by following proper installation procedures, protecting your floor, and maintaining it.

Let’s walk through these steps.

Follow proper installation procedures.

The Bessemeter S300 wood moisture meter with two other wood moisture meters in the backgroundWhen preparing for hardwood floor installation, read up on the type of wood you’re using and follow the specific procedures for it.

Here are some other best practices:

  • Make sure the flooring is being installed in a controlled climate that already has an HVAC system in place.
  • Use a moisture meter to check that the wood is at the right moisture content before installation. The NWFA (National Wood Flooring Association) recommends checking 40 boards per 1,000 sq. ft. of flooring.
  • Follow the proper acclimation process if the wood is not at the right moisture level.
  • Check that the subfloor is at the right moisture content. The moisture content of the wood flooring should be within 2–4% of the subfloor.
  • Put a moisture barrier or retarder over the subfloor. Check with the manufacturer to determine the right kind for your project.
  • Use the right type and amount of fasteners for your project.

Protect your floor

Once your hardwood floor has been installed, you’ll want to protect it.

To prevent dents and scratches:

Put protective pads on the feet of all your furniture and remove your shoes indoors. High heels and wood floors don’t get along very well!

If you have pets, you may need to take some extra measures to protect your floor. A good place to start is keeping your animals’ nails trimmed and coating your hardwood floor with a scratch-resistant finish. If you’re particularly concerned about certain areas in your home, add a large rug there and save yourself some worry.

To prevent moisture damage:

Use oil, lacquer, or varnish to finish the floor. Sealants can also help. How often you refinish your floor will depend on the type of flooring and the manufacturer’s instructions. Generally, solid wood flooring should be refinished every 7 to 10 years (but sooner if it’s looking dull and scratched).

In addition, you’ll want to seal gaps around windows and doors where moisture could slip in.

Put down rugs and mats, especially at entryways, to catch water puddles when your children come in with sopping shoes and jackets.

To prevent UV oxidation:

A window with a curtain to decrease the wood floor's exposure to sunlightPut curtains or blinds on your windows to lessen the floor’s direct exposure to sunlight.

If you like the sunlight streaming in, use a polyurethane finish that will help protect against UV rays. Or put UV films on your windows.

Maintain your floor

Maintaining your hardwood floor can be as simple as keeping a consistent climate and using proper cleaning techniques. Take good care of the floor now and you will not only prevent moisture problems but also preserve it for years to come—even up to 100 years!

Keep a consistent climate in your home by preventing drastic changes in temperature or relative humidity. If your region switches from high humidity in the summer to a very dry winter—as is the case for many states on the east coast—invest in a humidifier that will regulate your indoor environment.

When it comes to cleaning, make sure your cleaners are designed for wood floors and never pour them directly onto the floor. Rather than mopping with water, a cloth or spray mop for wood floors will do the trick.

It’s also good for homeowners to check areas where water might leak onto the floor—under appliances, sinks, etc. Though there isn’t an exact timing for how often you should do this, make it part of your weekly cleaning routine. The earlier you catch water leaks, the better!

The best way to deal with wood floor problems? Stop them before they happen.

A yellow Bessemeter wood moisture meter with a black case and a calibration verification reference
No one likes to deal with damage to their hardwood floors, and we hope you won’t have to! That’s why we’ve given you a plan of action to stop common hardwood flooring problems long before they happen.

Since moisture is a typical source of damage to hardwood floors, you’ll want to make sure you’re equipped to detect it. An accurate moisture meter will help you check moisture content throughout the installation process.

And if perchance, you run into damage, a moisture meter can help you assess the problem.

So, what are you waiting for? Visit our shop for some moisture meter options to suit your needs.

  1. “Moisture and Wood,” National Wood Flooring Association, p. 27. ()