How to Fix Hardwood Floor Problems: Cupping, Crowning, Chatter, and More

cupped hardwood floors

Knowing how to quickly identify and efficiently fix common problems with hardwood floors is an important skill to have.

Here are some of the most common problems that occur while installing hardwood floors — including cupping, crowning, and squeaky floors — and instructions on how to fix them.

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How to Fix Cupping

Cupping is denoted by wood that is raised on the edges of each individual floor board. The center of the board dips below the edges. This makes the wood appear to be in a “U” shape. (See the picture at the top of this post for an example of a cupped floor.)

Typically, cupping is a problem that stems from excessive moisture. Anything from pipe leaks to a still-wet concrete slab to improper HVAC usage can cause cupping.

To fix the issue of cupping the first and most crucial step is to assess the moisture problems. Take the necessary steps to stop or correct the source of the moisture problem. Once this has been completed, take readings with a moisture meter to confirm the wood is at the correct level according to the manufacturer’s specifications.

DO NOT sand a cupped floor. Sanding a hardwood floor while it is still cupped will result in a problem called “crowning.”

How to Fix Crowning

Crowning is typically a problem that is a direct result of cupping. Crowning is characterized by wood that is raised in the center and dips down on the long edges of the planks.

This issue comes from sanding a floor that was cupped and still had moisture issues. The cupped floor was sanded to be flat, but once the moisture levels return to an acceptable level, the edges of the plank were sanded down below the center.

To fix a floor with crowning, you must first be sure that the moisture levels are acceptable and there are no issues such as leaks, wet slabs, or improper HVAC usage. If you need a crash-course on testing moisture the content of a hardwood floor, check out our guide.

Once you are sure the moisture is at the right level, you must completely sand the floor to be flat.

Halo Effect/Picture Framing in Wood

The halo effect (also known as picture framing) is when the edges of a room appear to be a different color than the center.

The most common reason for the halo effect on a hardwood floor is when different sanding approaches are used in the same area. For example, picture framing could result from using 60, 80, 100 sandpaper on the big machine, but using 80, 100, 120 with the edger.

The fix for the halo effect is to re-sand the floor and use the same sanding schedule for the big machine and edger.

How to Fix Chatter Marks in Wood

Chatter marks are repeated imperfections on the floor that are between 1/2″ and 3/4” apart.

They are traditionally caused by some sort of failure in the big machine sander. Bad sandpaper

Lagler Trio

A multi-disc sander like the Lagler Trio can help you get rid of chatter marks.

alignment, uneven wheels, incorrect drum pressure, imbalanced drums, loose V-Belts, or failed

bearings are common issues that could produce chatter marks on hardwood floors.

The best way to prevent chatter marks is to make sure your big sander is operating perfectly. You may have to take it to a repair shop to have it serviced.

If there are already chatter marks on your floor one great way to fix them is by using a multi-disc sander like the Lagler Trio. The multi-disc sander is specifically designed for finish sanding. It is powerful enough to remove cross grain scratches but will not change the wood floor’s topography.

Read our blog about getting rid of chatter marks for more details about this issue.

How to Fix Squeaky Wood Floors

Hardwood floors with significant movement or noises could be the result of several factors.

If the floors were installed with improper nailing schedules or the incorrect adhesive, they will be loose and cause noise. If the subfloor is inappropriate for the wood floor being installed that could also be the cause the noise or movement.

Fixing the problem of movement and noise could be simple like adding adhesive to the problematic floor boards or top nailing. However, if the problem is extensive, then it may be necessary to reinstall the entire floor.

If you have any additional questions regarding these common problems with hardwood floors, feel free to contact us at (800) 737-1786 or

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8 thoughts on “How to Fix Hardwood Floor Problems: Cupping, Crowning, Chatter, and More

  1. Valerie Ewing

    We have an open floor plan with all new hardwood, I noticed the cupping right away, it’s getting worse. Why is this happening and what can I do about it. We are sick over it as we spent quite a it of money on this renovation. Please help

    1. Caran Baxter

      Hello. Sorry that you are not happy with your new wood floor. There are many variables that lead to a wood floor cupping, but they all have one thing
      in common, Moisture. I would definitely have your installer measure the relative humidity of the facility and moisture content of the wood floor
      and subfloor.

  2. Amy

    Is there anything I can do to reverse cupping in a two foot square area where a plant leaked water on the hardwood floors?

    1. Caran Baxter

      Hello. Thanks for the question. First and foremost address the source of the moisture and remove it. Unfortunately once the flooring has
      cupped the only real solution after it dries and reached Equilibrium Moisture content is to sand it.

  3. David Land

    I have a new (6 month old) on-site installation of 3/4 inch hardwood flooring that is cupping. Moisture is at 4.5%. I called the company who installed the floor and they said the moisture level was too high. I highly disagreed with them, as I am reasonably certain it should be at or about 6%. Being present for the installation, pieces of flooring were ripped and gently hammered into place, but very tight. Could the low moisture content or the tightness of the installation be the culprit for this issue? And it is not throughout the entire 1600 sq. ft. of hardwood floor. Most of this is where new wood was installed.

    1. City Floor Supply

      Hi David,

      We’re going to need a little more info in order to properly answer your question. What is the species, where are you located, how wide is the flooring, and is this material solid or engineered? When you say that the moisture is 4.5%, what was it measured with? What is the relative humidity? Is this install “toothed” into an existing floor?

      Sorry for all the questions, we just need a better idea of what’s going on.


  4. Laura Smith

    I am curious, my installer did not acclimate my 3/4″ white oak stained on site wood floors. They brought them over and installed the the next day. They did go around with a moisture meter on my sub floor and the new flooring and said that they were close enough to each other that there would be no issue.

    House is a 1960’s ranch with crawlspace. We recently replaced all visqueen vapor barrier and floor joist insulation

    Here we are with cupped floors They cupped shortly after install and have not gone down 6 months later. They specialize in wood floors so that is why this is all so weird.

    They claim that 5-7 days acclimation is not needed yet here I am with cupped floors.

    Any ideas?


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