9 Hardwood Floor Problems and Their Causes

By Samuel N •  Updated: 11/04/22 • 

Hardwood floors are one of the most popular types of flooring for most homeowners. A hardwood floor’s elegant look and natural characteristics add warmth, depth, and character to any room. Their visual appearance is also unlike other types of flooring, despite the many designs that try to emulate them.

Hardwood flooring requires proper care and maintenance from the time they are installed in your home. Normal wear and tear is normal and will depend on the usage of the floors. Because wood is a hygroscopic material, there will be changes due to the environment – Temperature and humidity.

Some changes in hardwood floors are normal and hardly noticeable. However, at times they can be noticeable and even destructive. Below are some hardwood problems to check out in your home.

1. Cupping

Hardwood floor cupping is the floor’s reaction to excess moisture. Hardwood floors are cup if the edges of the hardwood planks are raised in comparison to the center. Cupped flooring happens when the edges of the floor absorb more moisture, which makes them swell. Cupping leaves a concave shape on the wood planks like the one shown below.

Cupping (concave) in wooden floor strips

Cupping (concave) in wooden floor strips

Cupping can happen to even newly installed wood floors. The common causes are changes in moisture, subfloor moisture, leakages and spills, and improper cleaning and installation.

To manage cupping and reduce severe damage, first, you need to keep the moisture in check. Avoid high humidity and properly install the floors to stop subfloor moisture. Proper acclimation of the hardwood flooring to the environment they are to be installed should also be done. Read more about floor cupping and how to fix it.

2. Crowning

Crowning is the opposite of cupping. With crowning, the center of the wood planks bugles higher than the edges creating a convex shape. The cause of crowning, as you guessed, is high moisture. However, unlike cupping, installed hardwood flooring can swell or shrink on the underside, resulting in a slightly crowned or cupped appearance.

Moisture imbalance through the thickness of the wood can also cause crowning. Wood usually has a higher moisture content on the top. If it absorbs more moisture, this can create a crowning appearance.

If your hardwood floors are cupped or flooded, we normally advise against sanding them until the moisture content is stabilized. If they are sanded to remove the raised edges, this will result in thinner and lower edges. As the hardwood planks dry, the edges will go lower than the center, causing a crowned appearance.

3. Buckling

Buckling is one of the extreme ways wood flooring reacts to high moisture. Buckling happens when the wood flooring lifts from the subfloor. Flooding is one of the main causes of buckled wood floors. Other causes include subfloor moisture, leaks, high humidity, or wet mopping that leaves liquid on the floor.

Improper installation techniques can also cause buckling in nail-down, glue-down, and floating wood floors. These include improper acclimation, lack of expansion gaps, inadequate nailing, incorrect fasters use, improper application of adhesive, insufficient adhesive, and missing transitions among many other factors.

To avoid buckling, eliminate sources of moisture to prevent wood flooring from absorbing the moisture and swelling up. Also, hardwood flooring should be properly installed to prevent buckling.

If your hardwood floors buckle, allow them to dry back to normal levels before attempting any repairs. Afterward, you can remove and replace the affected areas if necessary. Read more about floor buckling, the causes, and how to fix.

4. End-Swell or Flared-Ends

This is a condition that usually happens before installing hardwood floors. Wider and thicker ends characterize it compared to the rest of the flooring board.

There are different causes of end-swell or flared=ends. If the boxes are opened during acclimation and exposed only at the ends, high moisture will cause the ends to expand at a higher rate than the rest of the board. The ends may be exposed to high moisture levels during storage or transportation, causing swelling. Changes in moisture can also cause fluctuations in the thickness of the, which can result in end-swell. This is usually common in rift and quarter-sawn flooring.

To prevent end-swell in uninstalled flooring, condition or acclimate the flooring properly. Also, avoid installing the affected boards, as they will be a problem in the future.

5. Warping

Warping is one of the extreme wood floor problems that cause the wood boards to change shape and no longer appear flat. There are different types of warping, which include bow, crook, and twist.

The main cause of warping is when a wood board shrinks or swells in relation to its grain direction. The shrinkage or swelling is affected by the size and how the wood was cut. It is common to see one side of a wood floor shrink or swell more than the other side due to moisture change, resulting in warping.

Improper handling and storage of wood boards after manufacture can also cause warping. This can occur during transportation, storage, acclimation, and if the packaging is opened or damaged.

To avoid warping for installed hardwood flooring, ensure proper acclimation before installation, use starters and finishers when installing, and cut off objectionable materials when installing. For installed hardwood flooring, replace the affected boards or repair the affected boards using fillers or siivers.

6. Splits/Cracks

Splits, cracks, and fractures can manifest by tearing apart or rupturing wood at different angles to the growth rings. There are different causes of splits, but the common one is mechanical damage from different sources.

Splits can occur if you mishandle the flooring boards when transporting or during installation. When installing hardwood flooring, avoid overdriven or improper fasteners that can crack the tongue of the boards. Adjust the air compressor settings to the proper level.

Apart from mechanical damage, splits and cracks can also show up when wood flooring shrinks because of low humidity or dry conditions. Excess shrinkage exposes prior damage to wood boards and exacerbates cracks and splits.

7. Wood Discoloration

Wood can change color over time and darken or lighten. The causes of color change in hardwood flooring are different and include oxidation, age, floor coverings, and resanding multi-species wood floors.

Oxidation or photochemical exposure is naturally occurring and cannot be prevented. However, the change in color due to oxidation will be more drastic in some wood species than others. This is very natural and should be taken into account when selecting your preferred hardwood flooring.

Age can also cause discoloration in your wood floors. Some wood species, such as American cherry, Douglas fir, Brazillian cherry, and Purpleheart, will darken with age. Others, such as Black walnut and cork, will lighten with age.

Parts of hardwood floors covered by furniture, area rugs, or exposed to less direct light can also change color slower than other parts exposed to direct sunlight. Move the furniture and area rugs periodically to help equalize the color.

8. Staining

Although hardwood floors are treated to prevent staining, they are not invincible and can be susceptible to staining. Different types of stains affect hardwood floors, ranging from moisture stains, iron stains, and chemical stains, among many others.

Moisture stains are caused by high humidity, spills and leaks, and pt accidents, among many others. To prevent moisture-related stains, eliminate the source of moisture and clean up faster after a spill or pet accident.

Chemical stains cause irregular spotting and discoloration because of the reaction of chemical or air pollution. Household chemical spills, cleaning products, reactive conditioners, bleach, and mineral deposits can cause chemical staining on wood floors.

Sanding or scraping can remove some stains from the surface. however, sometimes some stains cannot be removed by sanding, and the damage remains permanent. Replacement of the affected flooring is the only option to deal with stubborn stains.

9. Noisy Boards

Squeaking, popping, crunching, and hollow sounds are some noises that you’ll hear from hardwood floors. Some of these sounds are not a concern and are completely normal if they do not affect the performance of the floor. However, other times they signify old floors, improper installation, and damage or change in humidity and temperature.

Proper installation procedure from the time of acclimation to nailing down or laying glue-down flooring should be taken. For moisture-related issues, identify the cause and address it. Sometimes mis-milled wood flooring can also be the cause. Contact the manufacturer for individual board replacements or inject adhesives if possible.

Apart from the above hardwood flooring problems, you can also get sanding marks, wood color inconsistencies, hardwood flooring finish problems and performance, and many other problems. I have covered some of these problems in detail posts, and I’ll continue adding information for other problems too.

Samuel N

Samuel N is the founder of Improve Floor and has been in the flooring industry since 2005. Since then, his mission has been to make flooring easier for everyone. He helps countless people with flooring installation, finishing, maintenance, and repairs each year.