There is nothing more discouraging than applying an epoxy garage floor coating only to have it turn yellow in color or tone in areas of the floor at some point after application. This can happen in as little as a few months to as long as a few years or more. As frustrating as this may be, there is a reason why some epoxy coatings turn yellow.
So, let’s examine why this happens, provide some tips on how you can slow the process down, and discuss how to prevent a garage floor coating from turning yellow to begin with.
The primary cause for epoxy floor coatings turning a yellow color is exposure to U.V. light. Also known as ambering, when exposed to direct sunlight or strong indirect sunlight over a period of time, epoxy will experience a photochemical reaction known as polymer degradation.
The degradation of the polymers is what causes epoxy to change to an amber or yellowish color as well as experience a reduction in gloss.
This is a natural progression for epoxy and usually will not affect the performance of the coating for most garage floors. However, if exposed to direct sunlight for long periods of time, it can eventually cause chalking, deterioration, cracking, and even delamination of the coating. This is why epoxy coatings should not be used outdoors.
The epoxy in the image below was actually a medium gray in color. It has turned a dark yellowish color at the entrance to the garage. In addition, you can see where the epoxy was extended out past the garage door onto the apron outside. This section is actually chalking up and deteriorating. That is why it looks almost white in color.
Two lessor known causes for epoxy coatings turning yellow is extreme heat and oxidation. Of the two, oxidation is the more common.
If the hardener is exposed to oxygen, it will slowly begin to oxidize and turn yellow. When mixed with the colored resin, the result will be a color that has a slight yellow tint. This is one of the reasons why epoxy has a limited shelf life of approximately one year in an unopened container.
The most common areas for epoxy coated floors to yellow are at the front of the garage where the floor is exposed to direct sun and along areas of the floor where sunlight may come in through windows.
The example in the image below is from a DIY Rust-Oleum EpoxyShield kit. It shows a patchy area of epoxy that has been yellowing due to sunlight that comes through windows. You can still see some of the original gray color.
Epoxy floor coatings can slowly be affected from strong indirect sunlight as well. Even though it may not receive direct exposure from the sun, if the garage door is open for extended periods of time, the front half of the floor can slowly attain a slight yellow tint starting at the front and working towards the back.
Are there epoxy floor coatings that don’t turn yellow?
One important fact to note is that all epoxy will amber when exposed to direct sunlight or strong indirect sunlight – period. It’s just a matter of how long it takes depending on the quality of the epoxy, additives used, and the type of U.V. exposure.
As a result, you will not find any epoxy floor coating available that will not turn yellow under the right conditions.
If a garage floor coating company, manufacturer, or concrete coating sales vendor states that their epoxy will not amber when exposed to U.V. light, then we highly suggest that you take your business elsewhere.
But what about brands that say they have U.V. stabilizers in their epoxy? Doesn’t that mean it won’t turn yellow?
Many commercial quality epoxy coatings have added U.V. stabilizers in their formulas. These stabilizers generally do a good job of stopping loss of gloss, chalking, and delamination for epoxy exposed to sunlight.
These are typically marketed as being U.V. resistant. However, U.V. resistant is not the same as being U.V. stable.
U.V. stabilizers will only slow down or delay epoxy from turning yellow if it is exposed to sunlight for periods of time. The epoxy will still eventually amber if the right conditions exist.
What these U.V. stabilizers will do though, is help to reduce the intensity of the amber looking color providing it’s not in constant sunlight.
The budget friendly DIY epoxy garage floor kits that you can purchase from your local home improvement centers are generally the worst offenders for turning yellow.
These do not have U.V. stabilizing additives and typically consist of lower quality epoxy that will turn amber and lose gloss fairly quickly if exposed to direct sunlight.
How to prevent an epoxy garage floor coating from turning yellow
Ok. So, we have discussed the why and how of epoxy coatings ambering or turning a yellow tone. The good news is that there are ways to slow this process down as well as prevent it altogether.
First off, we want to state that if you are not one to keep your garage door open for any length of time other than to drive your vehicles in and out of the garage, pull out your trash cans and etc., then you are the least susceptible to an epoxy coating turning yellow. Even the low-cost DIY garage floor coating kits do well in that regards.
However, if you do like to keep your garage door open for periods of time, then there are some recommend steps that you can take to delay the process as well as the amber looking color intensity of the epoxy.
In addition, there are other options you can consider to prevent ambering regardless of how long you like to keep your garage door open.
The first step is to use a commercial quality high solids epoxy coating. This article here explains the differences in epoxy solids. Many of these high solids epoxy have U.V. stabilizers added. Even if they don’t, the premium ingredients and formulations will resist turning yellow much better than low cost epoxy coatings.
Also, consider your color choice. Ambering of tan and beige colors is less noticeable than shades of grays or lighter colors.
If applying a clear coat, do not use an epoxy clear coat. Garage floor coatings with an epoxy clear coat will actually look more yellow when they begin to amber.
The reason is that the yellow amber tone in clear epoxy is much more noticeable. Combine that with the color coat ambering and you can get a nice yellow or dirty brown looking tone.
Instead, apply a high performance clear coat such as polyurethane, polyurea, or a polyaspartic. These types of clear coats are U.V. stable. They will not amber when exposed to direct sunlight.
There is some debate as to whether or not a U.V. stable clear coat will slow the ambering process of epoxy down, however. Some installers have noted that it can work well for garage floor coatings that only see indirect sunlight.
Use more color flakes. Color flakes are made of acrylic and vinyl resins that are U.V. stable and will not amber. If you go with a medium to heavier broadcast of color flakes when using a U.V. stable clear coat, there is less colored epoxy exposed to turn yellow.
There are also options to create an epoxy coating system that is completely U.V. stable and will not amber regardless.
For those who prefer no color flakes or a light to medium color flaked floor, you can prevent your coating from ambering with the addition of a color tinted polyurethane coat.
You apply a polyurethane that is tinted to the same color as the epoxy after you put down the base colored epoxy coat. Next, broadcast your color flakes into the polyurethane and apply a U.V. stable clear coat. The clear coat is not required for this process if you opt not to use color flakes.
This type of hybrid epoxy coating system is completely U.V. stable and will not experience any yellowing.
The other option is to apply color flakes to full refusal. This is very popular and allows you to customize the look of your floor since you can choose and mix the amount of colors how you want.
The high solids epoxy coating is completely covered with the U.V. stable color flakes. You then apply the appropriate amount of U.V. stable clear coats to completely encapsulate and cover the color flakes.
Keep in mind that you cannot apply color flakes to full refusal on a low solids epoxy coating. They are not thick enough to handle all of the flakes. Examples would be Rust-Oleum EpoxyShield, RockSolid, and Sherwin Williams H&C Shield-Crete.
Lastly, you can apply a garage floor coating that is other than epoxy.
The newer single-part polyurea garage floor coating kits are becoming extremely popular. Though more expensive, these are extremely long wearing coatings that are actually easier to apply and are U.V. stable. They will not yellow.
Another similar option would be a single-part polyurethane system. Rust Bullet DuraGrade is an excellent example. It will not yellow if exposed to direct sunlight either.
If you are hiring a garage floor coating contractor, then you can opt for a polyurea polyaspartic floor coating or a hybrid like those we mentioned above.
Final Thoughts
One important point that we want to make is that the budget friendly DIY epoxy coating kits are the ones that receive the most negative attention for turning yellow.
As we had mentioned, these coatings are notorious for doing so if they are exposed to any type of strong U.V. light – direct or indirect.
The high solids commercial quality epoxy garage flooring kits are less susceptible to this for the reasons that we mentioned above. These are the type of kits and materials that you can purchase from quality online concrete coating vendors. You won’t them in home improvement stores.
Many of our sponsors that advertise with us are a good example of where to purchase such products. You can find a list here in this article if you are not familiar with these types of companies.
In most cases, the people who experience ambering with commercial quality epoxy kits do so after a period of years. Many times, they don’t notice as much because the process is so slow. Unless, of course, there is a distinct section such as the garage door opening that they can compare it to.
In short, if you take the steps that we have outlined above, you can slow down the yellowing process of an epoxy coating or even prevent it altogether with the right garage floor coating materials.
I’m thinking about epoxy for my garage floor that faces North. I do leave the door open for periods of time, but the sun never gets close to the floor. Will I still have a problem with it turning yellow?
Hi Steve. It depends on the quality of epoxy you use. The store bought DIY kits may still get some yellowing over time. However, many of the commercial quality high solids epoxy kits do very well in your scenario.
Yup it will still yellow. Have blinds on all my windows. After 3 years floor is yellow ing. More so at door openings Have light grey with gray black and white specks. Out side overhead door are disgusting!
I have a dark flake epoxy garage floor. There are whiteish sports from water on the front part of the floor. I have been told acetone will remove spots but this doesn’t sound like a solution long term. Company said it’s from oxidation and will not fix issue. I would like to put a clear finish over this section of floor. Any recommendations.
Hi Mark. I believe we need more information. When you say dark flake, do you mean that that it’s a full flake coverage? Is your floor exposed to sun at the front of the garage? If so, it could very well be spots that are deteriorating due to oxidation. If the floor was professionally done it should already have a clear coating applied, especially if it’s a full flake floor. If it’s not a full flake floor, then technically you can get away without applying one. Are you sure there isn’t one on the floor already? It’s rare for a company not to do that unless you were trying to save money.
Assuming it’s not a full flake coverage and there is not a clear coat applied, it will take sanding of the color coat to remove those spots. In addition, you can’t just clear coat one section of floor. It will look much different and stand out. It’s like polishing and waxing old paint on one half of the hood on a car. The polished and waxed section look much different than the rest.
I have a concrete overlay in my basement. The clear has begun to yellow In less than 6 months. Once this has happened is there a way to repair the top coat?
Hi Jason. Assuming this is epoxy you are referring to, it would require that you sand the clear off down to the bare overlay or color coat and then apply a new clear. Is there strong U.V. light that is entering through windows or do you use a lot of fluorescent lighting? It’s unusual for epoxy to amber in a basement unless it was poor quality and/or very inexpensive product.
It’s very odd had minimal exposure from light through the window. The overlay is white with black streaks almost like marble. Strangely the spots look neon yellow under light but brownish with normal light and it seems that the worst areas are over the black streaks. This was “professionally done” with a brand called Rock Tree.
Before you do anything, Jason, we would recommend contacting the company that applied the product and see what they have to say. What you are experiencing is odd and should justify an inspection by the installer.
Correction brand was Rock Tred.
Yes, we assumed that is what you meant. Rock-Tred has quality products and should not be providing a clear that will amber, particularly over a floor of your color. That is why we recommend giving them a call and/or the installer that applied it. Something is not right.
I need to refinish my garage floors. The existing epoxy surface was done about 17 years ago & has held up well with the exception of the area where I park my vehicle. The area under each tire has worn thru to the bare concrete & there is some yellowing near both doors. There is very little wearing of the epoxy on the rest of the floor. Since I plan on installing a new kit, ie new paint color, chips, topcoat etc, how aggressive do I need to sand the floors. I used a commercial product the first time around & plan on doing the same when I refinish the floors, maybe Armorpoxy I’ve read varying comments on how heavily the floors need to be sanded so any advice you can offer is appreciated.
Hi K. Degrease the entire surface first. After that, you need to either etch or lightly grind the bare concrete spots. They will be too smooth from the cars parking there and they may have some rubber contaminant that the degreasing and etching / grinding will remove. After that, rough up the entire surface with 120 grit sandpaper. A floor maintainer with a 100 grit sanding screen will get the job done faster. You can hit the corners and edges with a pole sander, orbital, or etc. Once you sweep / vacuum, wipe he entire surface down with denatured alcohol applied to a microfiber mop pad. You are then ready to recoat. We have an article on the process here. Depending on the type of coating system you plan to use, you may want to apply a thin coating to the bare spots first. Let them cure long enough before applying a full coat. This will help ensure those areas keep the same color tone.
I have a white epoxy floor. It looks great.
I have a few area rugs. The floor is yellowing under the area rugs.
Do you know why that might be the case and what can be done to stop / slow this?
Thank you.
Hi Gio. Is the epoxy actually changing color or is there a residue on the surface that has turned yellow? Also, do the rugs have a backing material and if so, what type?
Shea,
I used an epoxy (with flakes) on my garage floor about 12 years ago. No problems…It looked fine, but turned a little dull, so I decided to use EAGLE CONCRETE POLISH (gloss) to bring the shine back. It’s been about a year and now the section where the sun hits the floor when the garage door is open is turning whitish. Also, I left a yard waste bag filled with wet leaves on the garage floor and it also turned the floor whitish in that spot. I’d like to get rid of the whitish spots and generally just strip the concrete polish off the floor. I’d appreciate your input on the best solution, assuming there is one.
Hi Mike. As you found out, unfortunately, acrylic wax polishes are not the best (nor recommended) for an epoxy floor. The general rule of coatings is that any topcoat/clear coat needs to perform just as well if not better than the base color coat. The whitish areas are where moisture has penetrated the wax and gotten underneath. What you need to do is strip the acrylic wax off as you would for a vinyl floor. There are acrylic wax removers (Zep products) that work well. Use a floor maintainer with a stripping pad to remove all the wax. The process will most likely dull the epoxy finish. Once the wax is removed, you can use a green scrub pad (dry) to properly haze the finish of the surface to prep for a clear coat. Once done, sweep/vac and then wipe down the surface with denatured alcohol applied liberally to a microfiber mop pad. After that, you can apply an epoxy clear coat to bring back the luster and create a much more durable finish.
I have the Rust-oleum RockSolid epoxy floor coating with chips and their epoxy clear coat over that in my garage. I applied this myself. Floor held up well now for 8yrs but is yellowing. What would be my best option to fix yellowing problem?
Hi John. Unfortunately, there is not anything you can do to stop or fix this condition. It’s inherent with the RockSolid coating. What you can do is apply a new coating system that is U.V. stable and will not yellow. Assuming that your current coating is adhered well, all it would require for prep is roughing up the surface with 120 grit sandpaper and then wiping it down with denatured alcohol or equivalent before the new coating is applied. We have an article here that discusses the process.
What to do or how to repair severely ambered garage floor?
Hello Ron. Unfortunately, there is nothing you can do to fix the current coating. Once it has ambered, there is no changing it back. Assuming that the current coating is adhered well, you can recoat over it with the type of U.V. stable coatings we mentioned above. We have an article here that discusses how to apply new coats to an old coating.
I am painting my back patio (200 sq ft) with Tuf Top 289 waterbased acrylic. After applying the second coat I will medium broadcast paint flakes on the surface while it’s wet. I would like to seal in the flakes and would like your advice what product to use to do the seal. I live in Florida and the patio will be exposed to full sun most of the year.
I’m concerned about yellowing. Looking forward to your advice.
Hello Brian. Most acrylic sealers are U.V. stable and will not yellow. Tuf Top lists that as one of its features. We recommend staying with the same manufacturer and applying the Tuf Top 289 Clear over the color coat and flakes.
Thank you for your advice. I like Tuf Top products. Good, now I can get get started with the project.
Hi Shea,
I’m looking to have my concrete garage floor coated by a professional. I’ve got a number of quotes all pretty similar in price, prep & features. The difference being 2-3 companies mention they will use Epoxy base coat, flakes & polyaspartic top coat.
The other 2-3 companies mention they will do a polyaspartic base coat & polyaspartic top coat?
Looks like there is pros/cons with both. Epoxy being thicker & better bond to concrete & polyaspartic being no yellowing + 1 day process vs two.
My main question is will the epoxy base coat turn yellow if using a polyaspartic top coat?
What method would you recommend going with? Thanks!
Hello Ray. The big question regards color flake coverage. This can make a difference in your choice. Are you opting for a partial flake coverage or a full broadcast of color flakes that completely covers the base coat?
I believe it is full broadcast but I will double check. What are your thoughts with full coverage?
If it was partial coverage your answer changes I assume? 🙂
Color flakes are U.V. stable and will not yellow (amber). If you opt for a full broadcast / full flake coverage, then you can do the epoxy base coat for optimal adhesion and build thickness. If you opt for a partial flake coverage, you are better off with the polyaspartic base color coat to avoid any chance of yellowing some years after. The polyaspartic clear coat will not prevent any epoxy exposed to sunlight from eventually acquiring a yellow tint. With quality epoxy, if the garage door remains closed most of the time or the garage faces somewhat north, it will take several years before the epoxy begins the process, if at all.