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Two questions that we are often asked is how to recoat or apply a new coat of epoxy to an older epoxy floor that has already cured and can you apply a clear coat to an older epoxy garage floor coating? If you’ve done a little bit of research on epoxy application, then you know how important floor preparation is. So let’s discuss how to determine if your floor qualifies for a recoat and then how to prep the floor before you do.
When can you apply epoxy over an older coating?
There are many examples of when you can apply a new coat of epoxy over an older cured coating. The most common of these are for people who had previously applied a color coat and now realize that they want the glossy looks and advantages of adding a clear coat.
Sometimes it’s as simple as someone who planned a multiple coat flooring system and waited too long between coats, allowing the epoxy to cure, before applying the next coat in order to get a chemical bond.
Another reason is to renew the clear top coat. After many years of service in a busy garage, the clear top coat of an epoxy floor can start to show its age. With the proper floor preparation, you can add another coat of clear and make the floor look brand new again.
And then finally, you may have an older existing coating that is showing wear from years of heavy traffic and getting thin. As long as the floor is not experiencing any delamination issues, many times you can recoat right over a worn epoxy floor to create a brand new looking finish.
As long as the existing garage floor coating is a 2-part resinous product such as epoxy, polyurea, polyaspartic, or polyurethane, then you should be able to apply an additional coat of a compatible product without issue. However, to be safe you should always consult with the manufacturer of the new coating first.
When not to apply epoxy over an older coat
If the existing epoxy floor coating is peeling up or showing other signs of delamination, then you do not want to epoxy over it. There are bigger issues at play here that are causing the delamination. Applying a new coat of epoxy over such a coating will only lead to more problems. A complete removal of the old coating by grinding would be required.
If the coating is fairly worn with more concrete showing through than there is epoxy, then you will want to start fresh by grinding the floor.
Do not attempt to apply epoxy over existing concrete sealers. These need to be removed first as epoxy will not adhere to them. Also, floor paint is not a good base for epoxy and needs to be removed as well.
How to prep epoxy for another coat
The key to applying a new coat is to mechanically rough up the surface of the older coat to create enough bite for the epoxy to adhere to it. There are a couple of ways to achieve this.
The first is to use 120 grit sandpaper on an orbital sander or pole sander like this one at Amazon. What you are trying to do is rough up the surface, not remove it. The surface should look deglossed after sanding.
Once done, sweep up the heavy stuff and then vacuum the entire floor with a shop vac. Next, use denatured alcohol on a small towel and wipe down the entire surface. The denatured alcohol will remove all the fine dust particles, evaporate quickly, and make sure that the surface is clean.
The other option is to use a floor maintainer (buffer) with a 100 grit sanding screen. You can usually rent these fairly inexpensively from your local home improvement center. They should have the sanding screens to purchase as well.
This method will go faster than the pole sander and cover a lot of floor quickly if you have quite a bit of square feet to prep. Just remember to occasionally check the sanding screen for wear and to make sure it hasn’t clogged up. After you are done, vacuum the floor and use denatured alcohol as described with the sanding method.
If you have an older clear coat that you want to renew, then you will want to use 80 – 100 grit sandpaper or a 60 – 80 grit sanding screen first to actually remove a small layer of the coating. This will help to eliminate any deeper scratches and/or embedded dirt that has marred the finish.
Do the same if you have a worn coating that is adhered very well but has some spots where the coating has worn through to the concrete. The more aggressive grit will insure that the bare concrete will be prepped properly as well.
Floor prep such as this goes fairly quickly. Once you wipe down the floor with the denatured alcohol, your floor is ready for a new coat of epoxy or floor coating of your choice.
Steve Geschke says
Good Evening,
We epoxy coated our garage floor in 1998 on concrete that was poured in 1996.
We prepped it by powerwashing and with TSP, used the Rustoleum product and it turned out great and lasted pretty well but was starting to show its age. As such we wanted to freshen it up and change the color from the Rustoleum standard tan/brown to a darker color, dark gray to almost black. We purchased the Valspar product and had it tinted for their “Graphite” color. We cleaned the existing surface with the cleaner that came with the kit , then applied SealKrete Lockdown concrete bonding primer. We put the new coating down last night and we are currently letting it dry and cure. We are not happy with the color as it is too light. What can be done at this point ? Do I need to grind the floor ? Or sand it with an orbital sander or pole sander ? Then re-coat ? with what ?
Thanks in advance.
Shea says
Hello Steve. Did you use a an actual 2-part epoxy that you had to mix together before applying it or was it a single part paint that you stirred in the can and applied? We ask because SealKrete Lockdown is a single part primer and should not be used as a primer for a 2-Part epoxy coating.
Rudy Griffin says
Shea, wanted to ask if can I layover a polyasparic matte finish to an existing aliphatic moisture cure urethane?
Shea says
Yes you can Rudy. Just prep the older finish properly before you do and the polyaspartic will adhere to the urethane well.
jo says
ok, so I was told my HD that the Bear paint one part epoxy will cover the 2 part epoxy paint with no issue. but to my surprise when wet the paint peels off… now what do I do???
Shea says
Hello Jo. Did you prep the older epoxy first by roughing it up with sandpaper? If you didn’t the paint will most definitely peel, wet or dry. Our suggestion is to remove the paint using a floor buffer with an 80 grit sanding screen. Home Depot can set you up with a rental. Once the paint is removed and the floor cleaned up you can apply a new coating. We suggest going with a 2-Part epoxy coating. It’s much more durable than the 1-Part epoxy paint.
Aaron says
I did the bear concrete apoxy I put the clear coat over it but the clear coat did not have a uv rating and it all turned yellow. It’s 4 years old now. Can I repaint to make it look good again . It’s showing wear too thx
Shea says
Yes, you can Aaron.
Michael says
I used the Rustoleum Solid Rock two part epoxy on my garage floor. It looks great except for two small spots that peeled off about two weeks after it was applied. I am happy with the product, just would like to know if Rustoleum sells a touch-up kit that I can use to recoat the spots that have peeled.
Shea says
They don’t sell a touch up kit that we are aware of Michael. However, we recommend giving their customer service line a call. From what we have heard from other reader’s here, they have been very helpful when people have encountered issues. Our biggest concern is that the area that pealed either is too smooth and did not get etched well or it may have some contamination such as a greasy film, tire dressing residue or something of that nature. It’s important to make sure the surface is prepped well before you touch it up.
Kent Adlof says
I used to be a paint rep and I also sold Rustoleum 2-part epoxy. Yes, you need to etch the concrete well and rinse and let dry. You also need to do it when the temperature is not too cold. If it’s cold, it will bubble up and then the bubbles will pop and crater.
Jake says
I used a sherwin Williams one part epoxy. No peeling after 2years but with heavy traffic it’s starting to full. If I prep it with the sand paper poll and reapply will it stick and also would a clear coat be a good idea over the second coat? Thanks
Shea says
Hello Jake. If you are going to apply the same product then yes, it will adhere just fine. There isn’t a clear coat that is made specifically for 1-Part epoxy paints. They are a one-and-done type of coating. Most high performance clear coats will soften the paint since they are solvent based. You can apply a 2-Part water based clear epoxy, but the cost is double that of the paint. An acrylic clear can be applied, but history has shown that it does not do well in a garage environment.
Geren says
We applied epoxy recently and let it sit to dry. A few days later we noticed some spots peeling up. The rest of the floor is fine just a couple patches that peeled up. We are guessing that we didn’t let the concrete dry enough and the downpour of rain we had at the same time didn’t help the moisture level either. We are wondering if we can just apply new epoxy to the patches that didn’t take without redoing the whole floor? We used an all in one kit epoxy (Valspar garage floor coating kit) and plan to use the same product to fix the patches. Thanks!
Shea says
Hello Geren. We recommend checking those areas to make sure you aren’t dealing with a contamination issue first. Apply a couple small drops of water and see if the concrete quickly absorbs it. If it doesn’t, then there is something in the concrete that needs to be cleaned off or removed from the surface first. If it does absorb the water drops quickly, then you can reapply the epoxy. Just keep in mind that doing spot repairs like that with epoxy is not like painting a wall. The areas that you reapply will look slightly different than the surrounding epoxy.
Geren says
Great. Thanks so much!
Geren says
One more question, will I need to sand the concrete or anything?
Shea says
Just sand the bare concrete where the paint has pulled up.
Steve says
Can you apply a 1 part waterborne epoxy over an old 2 part epoxy? This is a 25k sqft airplane hangar, the flooring isn’t peeling. If so what prep or primer would you recommend?
Shea says
Hello Steve. Yes, you can apply a 1-Part epoxy paint over 2-Part epoxy. It just requires cleaning the surface and roughing it up with 150 grit sandpaper before application. However, we do not recommend applying it at all. 1-Part epoxy is not nearly as durable (abrasion and scratch resistant), nor is it even close to being as chemical resistant as true epoxy. Av Gas and Jet A will cause it to turn soft and blister. In short, it’s just a poor choice as a coating for an airplane hanger.
Suzanne says
We recently had our concrete floors done, tearing up the existing flooring (indoor), grinding it down, putting down a skim coat, acid staining and finally an acrylic finish. We originally wanted to get a polyurethane sealer, but we had to get back in the house. (This was all done by a licensed contractor). We are now noticing the acrylic surface is easily marred and I have been reading about various other sealers which were not offered to us as an option. Is it possible to put another surface coating over the existing acrylic (such as polyaspartic or epoxy) or must we first remove the acrylic layer? We had this done less than a month ago.
Shea says
Hi Suzanne. Yes, you would need to remove the acrylic coating first before you put anything else down. One tip you may want to try is waxing the acrylic finish. The wax acts as the sacrificial layer and protect the acrylic from getting marred.
John says
I have a 2 part epoxy thst i put down about 5 years ago, it is now showing signs of wear peeling from the sun hitting it. What do i need to do to apply a new clear coat?? Sanding l, power wash?? Any suggestions
Shea says
Hello John. Do you have a clear coat peeling from the colored epoxy or the colored epoxy peeling from the cement?
John says
Clear from colored epoxy
Shea says
OK, we recommend removing most of the clear with a sanding screen and floor buffer as we mention in the article John. The idea is to take it down to the color coat if you can. If you have a lot of color flakes/chips in the color coat, you will need to be careful not to take too many out with the sanding screen. Once you do that, vacuum and then wipe the floor down with denatured alcohol and you are ready to apply a new clear.
Jody says
Hi there, we made the mistake of painting our old garage floor with Valspar concrete paint by mistake. We were thinking to do another coat, then read the label, not for use Un garages! Doh! So, how should we prep for an epoxy coating? before we painted, we had power washed, and primed it for the paint. Thanks
Shea says
Hi Jody. You will need to completely remove the old paint and then prep the bare concrete by either acid etching or grinding. Many times a good pressure washer will remove latex concrete paint. Grinding will remove the paint and prep the concrete at the same time.
Shawn says
My garage had two coats of paint/epoxy. Pressure washing easily removed the top coat, which I assume is latex. I am not sure what the bottom coat is but it is intact with a few minor chips. I rubbed Xylene onto the base coat and nothing happened to that bottom coat. Is it safe to assume that the bottom coat is epoxy? If so, can I just rough sand it a then put a fresh coat of epoxy on it? Should I use a 1-part or 2-part epoxy?
Shea says
It sounds like a water based acrylic clear was used as the top coat Shawn. As you experienced, this type of clear is not the best, especially for a garage environment. If the pressure washer and Xylene test did not affect the color coat, then it’s fairly safe to assume you have a 2-Part epoxy on the floor. We recommend staying with a 2-Part epoxy in order to maintain the same durability of the color coat that you have now. Rough sanding will work just fine.
John says
Hello. Great article, thanks! I installed the Rust-Oleum 2 part epoxy to my 3 car garage about 10 years ago and it has really done well. There are a few spots where the epoxy has essentially worn off (not peeled off). I am sure that there is oil, gas and other fluids on the floor as well. I plan to power wash the entire garage with an floor cleaner and would really like to recoat 2 of the 3 bays. Based on the article, I believe I should sand the bays down a little and then recoat. Is there anything else I need to do?
Shea says
That’s about all that is required John. After you clean from the sanding, it’s a good idea to wipe the floor down with denatured alcohol just before you apply the new coating. This will remove any excess dust and debris from the old coating so that nothing gets trapped in the roller while applying the new one.
Jay says
Hello,
I have applied the rocksolid 20x stronger than epoxy garage floor kit about a year ago. I too discovered that coverage stated was less than advertised, and my roller fell apart half way through application. When I was done i was pleasantly surprised by the look and so were my neighbors. About 6 months later I started to see the first signs of peeling where the car tires typically are parked. Now you can see the concrete below the tires where both of our vehicles park. I am interested in refinishing the floor. what can I do to prevent the peeling under the tires? I’m thinking wash well, rent a buffer/sander and re-apply the coating. Maybe add a clear coat too? I didn’t put any anti-slip in the first time and last winter both of my kids slipped and went down in the slushy muck. It was really slippery. Any advice is appreciated!
Shea says
Hi Jay. One of the keys to avoiding hot tire lift is to get good penetration into the concrete as well as a thick enough coating. Your plan of attack is good, just make sure you have good absorption into the concrete where the car tires usually sit. Adding an anti slip additive into the final coat is a great way to reduce slip fall accidents. Just keep in mind that the additive can reduce a little bit of the gloss to the finish.
Dixie Catlett says
Our neighborhood community hall’s concrete slab floor was treated to a light tan epoxy finish (without color chips) 3 years ago at what was to us considerable expense. What a wonderful improvement over the previous peeling painted and bare concrete mess! Although we asked for an “epoxy floor” the contractor who did the work is no longer available to answer questions, so we don’t have the specifics on the content of the coating/coatings he used, but it was good work by someone experienced.
The Hall has nearly every-weekend use and we originally used a pushbroom and cotton string mops with detergent-based floor cleaners that may have taken off some of the gloss. Thanks to web searches that educated us recently, we just switched to cleaning with a dust mop followed by clear ammonia and hot water with a rubber mop, and so seem now to see more gloss finish. We are not sure whether we have clearcoat or not. We notice shallow surface scratches that retain dirt/stains (which is why we recently searched online for info on how best to clean), and now are wondering whether applying a clearcoat could help our beloved floor finish to last longer and stay cleaner.
How might we determine the content of our current floor coating(s) in order to select the correct clear coat and method to ensure a bond to our existing 3-year old floor coating system? There are a few tiny damaged areas along an edge where we could pull up a bit of coating if necessary to test it.
Shea says
Hello Dixie. By your description, it sounds like you have epoxy or a similar resinous type of coating and not paint. To verify for sure, apply some MEK to a rag and rub it on an inconspicuous spot on the floor. You can pick up a small can at your local home improvement center. If you have paint, the surface will soften (poke it with a finger nail) and color will come up on the rag. If it’s epoxy, the worst that will happen is a deglossing of the finish or a little bit of color on the rag. The surface should remain hard.
Assuming you have an epoxy coating, prep the floor as described in the article. The sanding will remove all the fine scratches and embedded dirt. After the new clear coat is applied, your floor will look brand new again with a nice glossy finish. As far as clear coat selection, we recommend a high performance polyurethane or polyurea clear coat. You can read more about them here.
jesse moreno says
I have textured flake floor currently and just want to paint it to a different color. the floor is currently in good to great condition.
do I still need to sand it and prep it before I add fresh coat of paint to it?
it is slightly on the glossy side.
Shea says
Yes Jesse, you still need to prep it properly. If you don’t, the new coat will peel up.
Dale says
Hello
I have the two part E from rust-oleum with a clear coat and it is 3 years old . I have flaking at some of the expantion cuts. There seems to be a white chalky substance under the the flaking area. I let the new concrete cure 6 years before applying the the epoxy. Is there any way to solve this .
Shea says
Hello Dale. The white chalky substance sounds like efflorescence. It is water soluble salt and minerals in the concrete that is left behind at the surface when moisture escapes. It is a sign that there is moisture of some sort under the slab. It could be from poor drainage around the garage or water that collects after a rain storm. Your best bet at this point is to make sure you have good drainage around your garage. The fact that it’s only showing up at the saw cut contraction joints after 3 years is an indication that it’s not a lot of moisture.
JEFF CROLLI says
Hello! I applied rust-oleum 2 part water based epoxy about 7 years ago. The only place that hasn’t lasted is where I parked my car in winter ….has come up completely, but all around that area is great. I have power washed it, scrubbed with TSP-NF and also pole sanded with the TSP solution to take gloss off. It appears less glossy and is clean and structurally sound. Now my question. Should I re paint with the same product or do you think the professional solvent based product would be better?
Shea says
The solvent base professional is better Jeff and shouldn’t come up as easy where you park the car.
Dan says
I epoxy coated my garage about 8 years ago with Rust-Oleum 2 part Tan Gloss epoxy and it has held up very well. There are some small areas were it has worn out (not peeling) and lots of areas still look almost new. About 10 months ago I added on to the garage so now I would like to redo my epoxy for the whole garage with Rust-Oleum Professional High Performance 2-Part Tan Gloss Garage Floor Epoxy.
Based on some information I read (including yours) it seems like I just need to sand the existing epoxy floor with 60 grit sand paper before applying the new coat but some info states I should remove the existing epoxy with diamond sander. Is it necessary to completely remove the epoxy using floor grinder and dyma-sert? It seems like if I go to the removing approach I would have to completely remove all trace of existing epoxy. Could the floor grinder and dyma-sert do any damage to the floor?
Do you think I should remove the existing coating to be safe or is that unnecessary work?
Shea says
Hello Dan. If a professional was applying a new coating to your floor they would completely remove any old coatings and properly profile the concrete by grinding. This insures that their coating will not fail from being adhered to a different coating instead of the concrete. It doesn’t mean that it would fail, but the properties of the new coating, particularly if it’s a higher quality coating, are dependent on how well the old coating adheres to the concrete.
In your case, you are applying the better professional version of the Rust-Oleum epoxy. This means that if you apply it over the old coating, how well it adheres to the concrete in that area is completely dependent on the old coating. If you are comfortable with that, then go ahead and keep the old coating. Keep in mind you still need to properly prep the new concrete by either acid etching or grinding. If you decide to apply it to the old coating, take a scraper to it first to make sure it doesn’t have any weak areas you are not aware of, then go ahead and prep as indicated above.
Dan says
Hi Shea,
Thanks for your reply. Yes I’m ok with having it bond to the existing epoxy. I took another look at the garage floor and I only see some wearing around high traffic areas where there are hairline cracks and other areas still look like when I applied it. I got a pole sander with drywall sanding screen 80 grit sandpaper today and gave it good scrub for couple hours.
We are in the process of cleaning the remainder of the floor and will be using the provided acid etching for the new garage floor tonight and hopefully we can apply the epoxy tomorrow on the half with the new floor. This will include some sections of the garage that has the previous epoxy. Once that dries we are planning to clean the other half with acid etch and apply the new epoxy over the existing.
Thank you.
Shea says
Great Dan, it looks like you have a good plan going then.
Larry Beal says
Dan, I used the Sherwin Williams 2 part Epoxy on my garage floor in March and covered it with the Sherwin Williams clear coat by the same company. I’m now getting tracking that appears to be in the clear coat and it won’t scrub off. The epoxy is solid and not coming up. It seems that all of my issues are with the clear coat. This is the first time I have used Sherwin Williams epoxy/clear coat and the last time. I would like to get rid of the clear coat and put another coat of Epoxy color down and most likely won’t apply any clear coat. What do you recommend and do you have a preference of brand. This is my 6th floor that I have put Epoxy on over the years and have never had a problem until I used the Sherwin Williams product. Thanks for your help and the info. that you have provided in the previous replies are very helpful. Thank Larry
Shea says
There are many places to acquire quality epoxy Larry, but most are not brick and mortar stores however. We recommend using a very high solids epoxy (greater than 90%) or 100% solids. Most quality epoxy can be found from the specialty vendors online who deal specifically in concrete coating products. ArmorPoxy is excellent as is Legacy Industrial, EpoxyMaster, Garage Coatings, and Garage Flooring LLC to name a few. As far as clear coats go, we only recommend a high performance polyurethane or polyaspartic/polyurea for most situations. Unfortunately the lower quality clears will perform as yours did.
We highly recommend that you call customer service of any company whose product you are interested in and tell them about your project. Customer service from these type of companies is much better than the brick and mortar stores and they can help you with your product choices as well as answer any application questions you may have.
ils says
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Where do I find this underwater epoxy? (shown in the image)
It is made by Rockwater
Shea says
We don’t see an image of the epoxy you are referring to. However, we recommend you contact Paul Oman at this website. He is an expert on marine epoxy and knows his stuff. Their website unfortunately is horrendous and needs updating, but if anyone can help you will marine questions, this guy is it.
Jamjet says
Hello,
I have recently purchased a house with a garage floor that was professionally done with a two part epoxy with decorative flakes. I’m not to hip on the color and which to change it.
I have reached out to a few commercial companies who sell epoxies. I’ve received two different answers on how to go about changing the color. Both have the common prep suggestions, use 80 grit on epoxy floor for adhesion. One suggest I should use an epoxy and a Urethane of the same color of choice. The other suggest if I want to change the color all I need is a urethane and not the epoxy.
Can I just go with a urethane of my color of choice if the floor is properly prepped? Or should I use both an epoxy and a urethane?
Thanks
JAM
Shea says
You can actually do it either way Jamjet depending on the color flakes. If you don’t like the current color flake color, you are better off applying epoxy first since it is much thicker than polyurethane and will do a good job of covering up the flakes. You would then apply the urethane afterwards and toss in your color flake of choice. If you like the current color flakes, then you could get away with just a different color urethane and then toss in more color flakes.
Jamjet says
Thanks Shea
I don’t like the current color of the epoxy or the flakes. I’m looking at just changing the color probably with no flakes. That being said, you would suggest both the epoxy and the urethane. Mainly using epoxy to cover the flakes to create an even surface so to speak?
Thanks
Shea says
That’s right Jamjet. We suggest using a floor buffer with sanding screen as well then. It will help to remove a lot of the color flakes and smooth out the ones remaining.
BG says
Hello- I recently put down a rustoleum water based epoxy with the flakes. Now looking at the finished product a week later, I would like to potentially add a second coat to make the epoxy a bit thicker. Any advice on how to deal with the flakes and prep the surface for another coat would be greatly appreciated.
Shea says
You are going to loose flakes during the process BG and the ones that remain in the coating are fine. A floor buffer with a sanding screen does a good job of removing a lot of the color flakes and smoothing out the remaining. The new coat will cover most of these flakes up anyways and then you can apply more after the coat is down. If it is a clear coat that you are thinking of adding in order to make the floor a bit thicker, then still no worries. Just use a pole sander instead. Your goal is to degloss the surface and rough it up. You will still lose some flakes, but not much. The remaining flakes may be roughed up and look dull, but once you apply the clear they shine right back up and look like new.
Scott W says
Hi! Love all the advice you are giving! I painted basement floor about six months ago. Last week had new sump installed, and of course they had to tear into basement floor. Now I need to repaint where they poured new concrete. How do you suggest blending into old painted floor? I originally used one part with flakes. Thanks!
Shea says
Hello Scott. Make sure the new concrete is clean and prepped according to instruction of the product used. After that, rough up the surface of the surrounding paint with 100 grit sandpaper. You can now apply the new paint. Make sure not to go too far past the sanded edges. If it’s an actual paint that you used and not epoxy, then it should blend fairly well. If it’s a 2-Part epoxy, then the new area is going to look more glossy and stand out since it does not blend as well as paint. The roller marks where it meets the old coating may show as well. When you apply the color flakes, be sure to start with a very small pinch and add as you need to. It’s much easier to apply more than it is to remove too many. Depending on how much color flake you have on the floor, it can help to disguise the patch work.