If you’ve used epoxy resin as floor coating in the past, you have most likely encountered discoloration. More specifically, you’ve probably seen epoxy flooring turning yellowish over time. This process is also called ambering. There are several reasons this process takes place. Although this is not necessarily a sign of degradation or of product inferiority, it’s important to understand why it is happening and how it can potentially be prevented, or at least slowed down.

Why Epoxy Coatings Turn Yellow

The following reasons are not exclusive for epoxy flooring. In fact, some instances may be more common in other epoxy resin applications like art.

UV Light

Exposure to UV light is the most common reason for epoxy resin turning yellow. When UV light hits the cured epoxy resin, whether directly or indirectly, the natural process of degrading the polymers within is sped up. This photochemical reaction is responsible for more than just turning the epoxy resin yellowish. It also causes the loss of gloss, delamination, cracking, and chalking in the coating. This process can happen in just a matter of months.

Extreme Heat

Long and continuous exposure to high temperatures can also cause discoloration in epoxy resin. Although this is probably the least likely cause of discoloration in most cases, it happens when epoxy supplies are placed in an area with consistently high temperatures. This causes the epoxy to turn to yellow or even light brown.


In most cases, epoxy floor coating is resistant to water and many other kinds of liquids. However, in some cases, if an opened container of epoxy resin is placed in a location rich in atmospheric moisture or when it is regularly exposed to water, contamination can result in discoloration.


In this case, discoloration starts with the epoxy hardener, not the epoxy resin. Oxidation turns the epoxy hardener yellowish over time. This starts to happen when the container of the hardener is opened for the first time and air is allowed to enter. The degree of discoloration depends on the amount of exposure. This also means that hardeners placed in larger bottles may be more affected.

How to Prevent Epoxy Resin Discoloration

The best way to prevent discoloration in epoxy resin happens in the product selection process. Some products have UV stabilizers that prevent the resin from losing its gloss, delaminating, cracking, and chalking. However, UV stabilizers only slow the process of discoloration. They do not completely stop it.

Some products also have Hindered Amine Light Stabilizer or HALS. This is an additive whose sole purpose is to prevent the yellowing process. It essentially diminishes the degradation cycle in the epoxy resin that causes the discoloration. A product that contains both a UV stabilizer and HALS will yield the best results against ambering and the other results of UV exposure.

Apart from that, making sure that your epoxy supplies have little to no exposure to moisture, heat, or air will also help in preventing discoloration of the cured product.

If you’ve already applied the epoxy resin, you can prevent discoloration by limiting the direct or indirect exposure to UV light. Even if only one area of the flooring is exposed to sunlight, for example, the discoloration will still spread to unexposed parts.

How Life Specialty Coatings Can Help

We offer a range of epoxy floorings and other Life Deck epoxy coating options for your needs. We have been a trusted name in the industry for over 55 years. We put your needs first as we continuously improve our products and services.

For more information about epoxy resin and other coating materials, get in touch with our team here at Life Specialty Coatings. Call us at 562-944-6391 or send us an email at support@lifecoatings.com. You can also visit our Contact page.

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