Knowing how to quickly identify and efficiently fix common problems with hardwood floors is an important skill to have, especially if you are a hardwood floor contractor.

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.

How to Fix Cupped Hardwood Floors

Cupping means that the 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. Wood is hygroscopic, meaning that it absorbs and releases moisture. When one side of the floor is exposed to excessive moisture, that side will expand, causing the whole board to warp away from that side. The sides of the boards curl up, resulting in the characteristic “U” shape of a cupped floor.

Sometimes, cupping is a result of normal humidity shifts that occur due to changing seasons, and will correct itself naturally as the seasons change. However, if the cupping is due to an underlying moisture problem, the floors will stay in this position until that problem is corrected.

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. Certain issues that can cause cupping include wet mopping the floor, plumbing leaks, a damp subfloor, and the environment fluctuating outside of a range of relative humidity (RH) that is acceptable for the floor.

Once you find the source of the moisture and correct it, verify that the floor straightens out within the next few weeks. If not, it could be permanently damage and in need of sanding and refinishing or, in some cases, board replacement. 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 a Crowned Hardwood Floor

A crowned wood floor is another problem that is usually the result of a moisture issue.

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 can either come from a moisture issue that is affecting the center of the planks, or from sanding a floor that was cupped and still had moisture issues. In the latter case, a cupped floor was sanded 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 find and correct the issue that is causing excessive moisture, which can include 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 that the moisture problem has been corrected and the moisture content of the floor has returned to the right level, monitor the floor for a few weeks to see if the planks return to normal. If not, the boards must be sanded and refinished or, in some cases, completely replaced.

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, and 100 sandpaper on the big machine, but using 80, 100, and 120 with the edger. Improperly blending the field of the floor with the edges can result in the hardwood floor stain absorbing differently, leading to this dreaded “halo effect”.

The fix for the halo effect is to re-sand the floor using compatible sanding schedules with the big machine and edger, ensuring that you effectively blend the field of the floor with the edges. Water-popping the floor can also help the stain absorb evenly.

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

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, it may be necessary to reinstall the entire floor.

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