Updated: Aug 16, 2021
Like all organic materials, wood changes color when exposed to the elements, including light. This is due to the process of oxidation, which simply cannot be prevented. Exposure to light is usually the biggest culprit causing discoloration in hardwood floors. This could be due to exposure to either UV rays or exposure to the light emitted by lightbulbs, especially fluorescent lightbulbs, but there are several other culprits as well.
Wood floor discoloration – why does it happen, and what can you do to prevent it?
Culprit #1: Rugs
Fading and discoloration in a wood floor may be caused by rugs. A rug blocks the UV light from hitting the floor, which can cause uneven fading of the wood.
Uneven discoloration of wood flooring is sometimes caused by a rug. Rugs block UV light, which causes uneven fading.
The solution? Move the rugs every so often and check underneath to ensure that any discoloration is happening evenly.
Culprit #2: The Species
Certain species of wood floor are more prone to fading and discoloration than others. For example, American Cherry and Ipe darken over time with exposure to UV rays.
Different species of wood vary in their reactions to UV exposure. Light-colored softwoods such as pine darken; dark woods such as walnut usually lighten; while some dark woods such as cherry and mahogany darken.
Make sure you know about the natural discoloration that is bound to be significant in your chosen species. The only way to prevent natural discoloration in this case would be to pick a different species. If you do not want to deal with significant discoloration, you might want to opt for a light hardwood such as oak, maple, birch, ash and poplar––the color of these species tends to change very little over time relative to others.
Culprit #3: The Finish and/or Dye
You should know that the color change might be dramatic with certain types of finish.
Clear finishes vary in initial color and in how fast they darken as they age. Water-based finishes have no significant color when initially applied, and don’t tend to yellow with age. Oils and varnishes––while they are the most vibrant when first applied––also yellow the most as they age.
Much more susceptible to light than the finish itself are the colorants used within the finish, especially dyes.
All dyes fade fairly rapidly in sunlight––they usually experience significant fading within 6 months to a year. They fade slightly less rapidly under indoor lighting.
What Can You Do If a Hardwood Floor is Discolored?
The key is to educate yourself about potential discoloration issues. Know that some degree of fading or discoloration is inevitable, especially if they choose a certain species or finish and the wood is exposed to direct sunlight.
If you pick a species that is prone to significant discoloration, there’s nothing much you can do aside from waiting for the fading to equalize or sanding the floor down, hoping that the discoloration is shallow enough to be removed.
With flooring that receives direct sunlight, checking underneath the rugs and moving them often can help to even out the discoloration.