Although epoxy resin is durable in other ways, unfortunately, it will break down in direct sunlight because its chemical structure becomes unstable when exposed to UV light.
Due to this, epoxy resin is better suited for indoor coatings, and should only be used in facilities such as factories, warehouses, commercial kitchen, offices, and homes.
Indoor Epoxy And UV Lights
However, being installed indoors does not protect the epoxy from all UV light, and they can still become damaged if windows are not laminated with a UV blocker.
Indoor epoxy can also become damaged by UV light from fluorescent lights and heat lamps.
Although UV exposure leads to film issues, there is not much of a risk of chalking or cracking on indoor epoxy floors, as they do not need to contend with rain or extreme temperature fluctuations.
Delaying The Damage Caused By UV Lights
Even though UV light can cause damage to epoxy over time, there are some formulations that can delay this damage.
One approach is using a combination of UV absorber with HLAS (Hindered Amine Light Stabilizer). This will delay the effects of the UV light, however, eventually in outdoor applications the UV stabilizers will have maxed out their ability to absorb and will no longer be effective. Nevertheless, the UV stabilizer approach is sufficient to enhance color stability of epoxy in indoor applications, especially when there is minimal lighting from windows.
How Long Do UV Stabilizers Remain Effective?
How long these UV stabilizers are effective is difficult to evaluate. Typically, they can be made to be UV resistant for a few months or even a year.
Additionally, there are UV blocking zinc nano additives available, but these additives prevent the epoxy from curing properly, which causes it to have inadequate mechanical strength.
The effectiveness of these nano additives is not proven in all formulations, and even with the additives it will still not make the epoxy as UV stable as aliphatic polyurethanes, polyaspartics, or acrylics.
Will Aliphatic Urethane Protect Epoxy From UV Damage?
One misconception a lot of resinous installers have is that a clear coat of aliphatic urethane will protect the floor from discoloring. While it is true that aliphatic urethane will not discolor, it will not protect the epoxy base coat because the UV light will actually penetrate the aliphatic topcoat.
However, colored aliphatic urethane can protect the floor from UV damage.
With all of this in mind, the best way to have a long lasting epoxy floor is to get an industrial flooring expert with substantial experience to evaluate the condition of your epoxy floor.