There’s something very special about hardwood flooring. Wood is a lovely, organic material that can give warmth and personality to a space with its varying colors and natural grains. But did you know that hardwoods change their color over time? It’s because of photosensitivity. Simply put, something that’s photosensitive will either lighten or darken when exposed to natural and artificial light.

Many people welcome the aging-related changes in wood because they can give it a special patina and beauty. Getting back to the color variation, there is also an inherent variation in color between veneers and solid wood of all kinds. Veneers are sliced from a long and dried in a matter of just a few minutes, while a one-inch solid wood board will take between 25 and 45 days to dry, depending on the species. A good suggestion is to accept that the color of the cherry walls and furniture will mellow over time and that no one will even notice a
difference after a year of light exposure.

Understanding and accepting the fact that the color of wood species will vary to some degree with exposure to light and oxygen will help to develop reasonable expectations when specifying sustainable American hardwoods in design.
But also, there are a few things you can do to stop or slow down the process if you don’t like how the color of your wood flooring is changing.

What Is Photosensitivity?
The degree of wood’s photosensitivity determines how much it changes color when exposed to light. The quicker a wood changes color when exposed to light, the more photosensitive it is. The mechanism through which light energy causes chemical changes to occur is referred to as a “photochemical reaction.” More specifically, when we’re talking about wood floors, it’s UV light that has the most impact on color change, which is the primary effect you’ll see over time. As discussed in my post about aluminum oxide finishes in hardwood flooring, a floor finish can minimize the effects of UV light, since all wood floors will change color slightly. But, in certain species like Jatoba, for instance, the possibility of a pronounced color
change over the years is well documented.

The tanning process of our skin is a familiar example of how sunlight affects wood. The photochemical reaction in wood is much slower though. It is known that certain extractives in the wood are responsible for its photosensitivity.
The most common change is that the wood will become darker in color. And the change that occurs will depend on the type of wood, the finish, and the amount of sunlight exposure.

Certain Woods Change Color More Than Others
While all hardwoods are photosensitive to some degree, certain types are more sensitive than the rest. For example, when first cut, walnut timber can range from a light pale brown to a dark chocolate brown. When exposed to sunlight, however, a dark brown walnut can lighten to a golden-brown tone over time.

Another wood that’s more prone to photosensitivity is tulipwood, also known as Poplar. When first cut, the color ranges from a green to a purple tone and can transform to a warm milk chocolate brown over time.

Cherry wood, both American and exotic species, is the most photosensitive of hardwoods. It will change from a pink tone to a red-brown tone over time.

Cherry is sensitive to all light, even incandescent light. Its heart color will move eventually from a pinkish color to light reddish brown. If there is a rug covering part of a cherry wood floor you will be able to lift that rug a year after the floor is installed and see that the exposed part of the floor is a darker color than the section protected by the rug. Eventually, all of the colors will even out, but it takes time.

In tulipwood, the heartwood, which ranges in color from green to purple when freshly cut, will transmute to a lovely milk chocolate brown color after light exposure. The sapwood color will remain a light creamy color.

Light-colored woods like birch and maple will change color more quickly than dark woods like walnut and mahogany. This is because lighter woods have a higher degree of transparency, meaning the wood grain is more visible and reacts more to sunlight and other environmental elements.

On the other hand, dark woods have a lower degree of transparency and are less affected by sunlight. This is why they often have a richer color that lasts longer.

Here are some examples:

BEECH: changes color to a medium degree over time, with the orange colors fading slightly and ambering.

EUROPEAN MAPLE: changes to a more golden color over time.

CHERRY: changes very fast and dramatically, darkening to a dark reddish color.

ASH: changes from a lighter tone to a straw or tan color over time.

MAPLE: changes color from a creamy white to a golden color.

JARRAH: changes color to a much darker tone over time.

WHITE OAK: changes color to a darker or ambering tone.

WALNUT: changes to a lighter golden-brown tone (the only one that gets lighter over time).

JATOBA: changes over time to a darker, almost vibrant red tone.

As can be seen in the table above, some wood species, particularly exotic wood species like Jatoba but also Tigerwood and Cumaru, have significant color changes. They might eventually show up in a completely different color.

So, before selecting your hardwood flooring, seek professional guidance on how the color of your wood floor will vary over time. We, at Teddy Hardwood Flooring, can assist you with your selection. And keep in mind that the hue of your brand-new wood floor may differ from the worn-out sample you viewed in our store.

How can I prevent my wood floor from changing color?
As we’ve seen, UV radiation is the key factor contributing to color changes in your wood floor. The fact is that it isn’t much you can do to stop that process entirely.
Nevertheless, there are things you can do to ensure that your floor at least changes color evenly, without having certain parts that are significantly darker or lighter than others.

Install Blinds or Curtains on Windows
It makes sense that if you can keep sunlight off your floor, it won’t fade as much. Drapes, curtains, shutters, or blinds are some of the best defenses against fading hardwood floors. If you keep them closed on the side of your house when the sun is hitting the windows it will drastically cut down on any UV and infrared light reaching the floor.

If you have mini blinds or other types of horizontal louvers and you don’t want to shut them completely, position the slats so that they angle upwards allowing the sunlight to be directed towards the walls and ceiling instead of towards the floor.

There is also the option of motorized screens, shades, and blinds that can be fitted to the inside or outside of windows. While these will be a bigger investment initially, they make up for it in convenience. You can set a timer so they will automatically extend during the hotter part of the day (when you’re most likely at work) and then retract afterward to allow light in when the UV and IR rays are not so strong.

Rearrange Your Furniture Periodically
From time to time, rearrange your furniture and floor coverings to allow sunlight to hit the previously covered areas of your floors. This will equalize the UV and IR light exposure and even out the fading process so a consistent color will be achieved within the entire room.

Rearrange Your Rugs Periodically
Move Rugs from Time to Time. If you have rugs on your wood floors, rearranging them periodically can help prevent the color from changing unevenly. As we have seen, the sun will naturally change areas of your floor that it hits more directly, so by moving your rugs around, you can help keep the color more even. You may also, at least, consider removing the rugs during the sunnier months and replacing them in the darker winter months.

There are also other options you may consider, such as:

Finishes with UV inhibitors:
Finish manufacturers are continually trying to find solutions to this problem of fading and color change. Unfortunately, at the moment there isn’t a finish that can completely stop this process. That’s the case with prefinished as well as site finished. There are finishes though that will slow the fading process down and it’s worth looking into using one of these products. The best finishes to slow down fading at the moment are high-end water-based systems.

Staining: If you’re going to have your floors stained then ask for a pigment-based stain instead of a dye stain. Pigment stains are more colorfast than dyes. A floor with a pigment-based stain and a high-end professional water-based finish will keep its color far longer than a dyed floor with an oil-based finish.

Window films:
The next step up is to apply a specialty film to your windows. These thin multi-layered films are designed to drastically cut down the UV and IR light while allowing different percentages of visible light to come in. Some endless brands and companies manufacture and install these coverings so do your research well before committing. 3M is one of the biggest and most reputable, you can see some of the options they have available here.

One of the best ways of stopping the sun’s harmful rays from damaging your floors is by blocking them before they even get to your windows. Awnings work great in this regard. You can get them in retractable or stationary designs and there are many different types of materials and styles to suit all kinds of houses.

Low-E glass windows:
If you are doing an extensive renovation and are swapping out windows, or you’re building a new home, you should look into low-E (low-emissivity) glass windows. These windows have special coatings that do a great job limiting the amount of UV and IR light that passes through the panes. There are a few different types of Low-E glass windows and you need to talk to a glass professional to see which ones are suited to your home.

If you are still concerned about the color of your floor, you can always contact a hardwood floor refinishing professional to have it refinished. This will give you a fresh start and ensure that your floor looks its best. Teddy Hardwood Flooring has a team of hardwood floor refinishing specialists that are ready to assist you with your project.

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