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.
Thanks Shea, I am happy with the gray and don’t want to remove the old product; can I use rock solid or is Eopxyshield best? (Rock Solid seemed easy to use).
Yes, you can use RockSolid.
Thanks so much for all of your information, it’s been so helpful. I used the Epoxy Coat Super Rejection Kit in my 400 sf garage this weekend. I wanted a smooth mirror finish, but it is very rough and bumpy due to the amount of chips soaking up the clear. I’d eventually like to add another layer of clear to smooth it out, but wondering when you rough up the surface for the mechanical bond, will the scratched surface show through if I just clear over top of it?
Thanks!
Hi Bret. A textured feel to the surface is common for full flake floors. It actually takes a few applications of clear depending on the the type of coating used to create a very smooth surface. When you rough up the surface to recoat later, it should look dusty white and scratchy after it is vacuumed and treated to a solvent wipe. Once you apply the new clear it all goes away and looks pristine again.
Hello, I did apply Epoxy (Rust Oleum brand) on my garage floor 2 days ago and already sprinkled the flakes.
I would like to apply another layer tomorrow, I did not do a good job on the first layer 🙂
Would this be ok?
thanks for the advice
Art
Hi Art. EpoxyShield allows for up to 4 days to recoat. If you get it down tomorrow you will be OK.
thank you 🙂
Hello – thank you for this article. It’s very helpful. I have a question about my existing epoxy floor (my porch). My wife sprayed lysol on her shoes which has appeared to discolor the epoxy floor (white). I’ve tried to clean it but the discoloration remains. I’m thinking I’m going to have to redcoat the epoxy (it’s my porch and not a large area). It sounds like I should sand the original coat with 120 grit sandpaper and apply a new coat. I was thinking about BEHR 1 gal. Slate Gray Self-Priming 1-Part Epoxy Satin Interior/Exterior Concrete and Garage Floor Paint. Does this sound like it would fix my problem? Thank so much.
Hi Ryan. Yes, you have the application procedures correct. The product you have selected will work well on a porch. It’s a 1-part epoxy paint which is a latex acrylic paint with a little bit of epoxy resin added for durability. This type of paint does not amber (yellow tint) from U.V. light like a true 2-part epoxy coating will.
Thank you! Much appreciated.
WHat do you do when the epoxy floor has a very textured surface. What kind of sanding implement would work to get into the deeper recesses of the coating? I was thinking about using a scrub pad for a 17″ floor maintainer (buffer) but didn’t know if there was something that would work better.
Hi Philip. Yes, that would work well. We recommend using a green pad.
I’m sure you have answered this many times. My basement floor was painted over 15 yrs ago using a 1 part acrylic epoxy. My special needs kids have started picking at the floor. So a small scrap has turn into a 2 inch area. Can I just sand this down & apply another acrylic epoxy? Or will the now 2 inch areas show? Thanks
Hi Jeff. Yes, you can do that. We would suggest just painting the area that exposed the bare concrete first to fill it in. After it has died you can then repaint the entire floor and it should not reveal where the bare area was.
I want to redo the clear coat on my 2-part epoxy garage floor, because the original clear is too dull and dirt is being ground into it. With what do I clean the floor in order to apply a new clear coat – and what product provides a high gloss finish?
We have an article here about how to apply a new coating to an older one, Michael. What brand of epoxy and clear coat do you have down now?
Scrolling through the comments pretty sure I know the answer but I recently coated my floor with the rustoleum product and when I went to do the clear coat I totally messed it up. Tons of high and low spots. (Should of been doing it at 12am) anyways From what I read I should be able to sand it down and try and reapply a new layer of clean on there. Thank you!
We’re glad you found the answer you were looking for, Carter. 🙂
One thing I forgot to mention was because I got it so thick it has already yellowed. Will that go away if wanted down?
You can’t water it down, Carter. The only way to get rid of the yellow look is to sand it down to the color coat.
Hello!
I just applied Rokrez Metallic Garage epoxy today and I have several small dry “holes” that popped up during the process. Not sure if it was because I laid it to thin or if I didn’t get the garage floor cleaned well enough. Unfortunately I’m headed out of town for a week and won’t be able to get more product in before I leave. Would this sand and recoat work when I get back? In the places I laid it thick it looks amazing and without the holes and I would love for the whole floor to look the same! Thanks.
Hi Kris. Yes, sanding and recoating will take care of it. What the epoxy experienced is something called outgassing. It’s caused from moisture vapor that is in the concrete gets trapped under the coating. It usually happens if the floor was wet prior and not allowed to dry long enough or when a thick coating is applied when the day time temperatures are still rising. That is why an epoxy primer is always recommended when applying 100% solids epoxy.
Well that makes sense. I cleaned the floor the day prior and thought it was dry before I started. I’m doing this floor in the panhandle area of Florida so I actually had to wait till the humidity came down and ended up doing it around noon. I’ve ordered two more kits and all the stuff to scuff it up. Looking forward to fixing it so it all comes out like it’s supposed to! Thank you so much for he help.
You are welcome, Kris. The second coat should go on real nice since the first coat essentially has acted as the prime coat.
I want to epoxy an older floor. It looks grey and I don’t know if it is epoxy. Some areas are grey some look like cement. If I could insert a picture I would. Any thoughts on how to proceed?
Hi Anthony. If you want to apply a quality coating, then we highly recommend grinding the surface to remove any existing paint or coating in order to apply the new coating to properly prepared bare concrete in order to get the best adhesion and performance – particularly when you don’t know exactly what was applied beforehand (brand and etc). One way to identify paint vs a true coating is to liberally apply some acetone to an area and then scrub it well with a rag. If the surface softens or bleeds a lot of color then it’s paint. If it doesn’t do anything or slight discolors, then it is epoxy. Coating should never be applied to paint because they will peel up just as easily as paint does since that is what the coating is adhered to. If it’s a coating and you want to preceded without removing it, then just follow recommendations in the article.
7 years ago I grinded down my garage floor and put down the rust-oleum 2 part professional epoxy and it has held up very well but it’s kinda yellow and a little dull where sun gets it and it has some dark spots where tires sit. Can I sand it down with 120 grit and apply more clear to bring it back? It’s not so bad that I am going to completely grind it down to bare concrete and do it over again but would like to make it look better.
Hi Mike. Yes, you can do exactly that. It will bring gloss back to the floor as well. The sanding may remove the dark spots where the tires sat, but it will do nothing for the yellowing. That goes all the way through the coating.
Hello, I applied rustoleum epoxy floor on my garage about 2 months ago and it is still tacky but not soft, I am going to be re applying soon. I’m assuming the temp was to cold and it never fully cured. Just feels like tape stuck to shoe when walking on it, will a light sanding be sufficient before applying new coat? Thanks in advance
Hello Piero. You will need to completely degloss the surface by sanding with 120 grit sandpaper.
Thank you for your fast response, sanding by hand sufficient? Or machine rental needed?
You can sand by hand using a pole sander. If you want to get it done much quicker, you can rent a floor maintainer with a green scrub pad. Use it dry (no water) and it will do the same job.
Hello. I just applied Rokrez garage floor epoxy last night. It was rather humid out and my pot life was only about 30 min. I was in the middle of spreading with the roller when it got real hard and tacky. Now my last section right before it hardened is not smooth and the finish looks tacky. I only finished about 10% of the garage before it became unusable. I have another kit, but realize I will need several more (3 -car garage). Unfortunately all suppliers are out of this product and I will have to wait several weeks to receive more. To fix the area where it hardened too fast, can I simply sand to make it smooth and then re-coat? Secondly, since i’m waiting several weeks, will I run into issues when I try and paint next to the small area that was already completed? Hoping I don’t nee to re-sand and then start the cleaning process over again. I already etched, will the pours in the concrete stay open for awhile, or do I need to re-etch if I don’t work on again for several weeks? Thanks!
Hi Dave. As you found out, it’s very important to pay close attention to temperature and humidity the day of install. The data sheets for all epoxies will discuss this. You can sand the surface with 100 grit sandpaper to smooth thing out and prep it for recoating. Just be aware that this particular section may look darker than the rest of the floor since it will have two coats. The concrete that was etched will not change as long as you keep it clean until more product arrives. If it gets dirty, be sure to clean it real well first and let it dry for a day or two.
Thank you very much for your help.
Hi, I coated my garage using some industrial coating, can’t remember exactly, anyway for 2 years it looked great and no issues, then I had about a gallon of clear coat and silly me decided to apply a second coat, no grinding or prepping, just cleaned the floor and applied the 2nd clear coat, then the yellowing started to happen, this is about a year ago, over time the yellowing has stripped away on some areas mainly where I park, and I can see the original where still looks good, I think that when I applied the second coat since there was no grinding the clear coat just created a barrier and moisture is in between creating the yellowing, again on the spots where it has peeled off the floor looks as good as it was on day 1, my question is , can I use a buffer or similar to remove that top coat ?
Hello Mike. Our guess is that you used a clear epoxy. Epoxy is not U.V. stable and will turn yellow (called ambering) when exposed to sunlight or strong indirect U.V. light. I’m surprised is stayed adhered as well as it did without the proper prep. We suggest using a floor maintainer with a 40-60 grit sanding screen to remove the clear coating. You will go through a few screens in the process. The removal will also rough up the current colored base enough to apply a new clear. We suggest using a clear polyurea or polyurethane to avoid ambering. The new clear will will make the color coat look like new again. FYI – do not use polyurethane for wood floors and furniture. You will not find any of these products from a home improvement center. You will need to source them from a concrete coating vendor.
Ok, I think I left the part that I did apply clear coat when I first painted the floor and also fully prep the prep the floor, for 2 years no issues, not yellowing or anything else, then I applied a second coat of clear and immediately started to turn yellow, is it possible to just remove that top clear coat, the second application, I don’t think is bonded to the first since I did not prep the floor the second time, I did the 1st time.
So since is not bonded moist is in between , I think is more rust that anything else since there is very few windows on just one side of the garage.
is over 1400 sq ft, there are some sections I did not apply a second clear coat, laziness did not wanted to remove cabinets, etc, and those sections still look like day one, perfect.
any other suggestions based on this?
Yes, it’s the same process as described, Mike. Just remove it to the good coat of clear. If there was moisture on the floor when you applied the second clear, you would have had all kinds of issues with clouding and the epoxy would peel up by hand in those areas.
Perfect, thank you.
I would imagine this will create a lot of dust, Do I need a special respirator or a regular dust mask will do?
Thanks again
A regular dust mask will do, Mike. The dust kicked up does not contain the silica like concrete dust does.
Hi, I had a young man and his company apply an epoxy floor but it did not go as planned, there are holes and it was hard to get the workers to come back and finish – technically there is no topcoat. I want to sell the apartment and am not sure what a new buyer would like to put down, floor-wise, whether they would like to finish the process with epoxy and proper coating / sealant or put down tile or vinyl plank. Is there a simple wax I can put on the floor as a temporary solution? Will Johnsons wax work for a short term of perhaps 3 months?
Hi Mary. You can wax epoxy if you like. However, it will degloss it slightly and it won’t change the fact that you have what I assume are bubbles in the coating.
Hi – I’m not sure if I understand some things correctly. We have a two part epoxy on our garage floor that has yellowed. We have cleaned it well, but of course a lot of yellowing remains. Are we able to put another coating of the same along with more flecks? But only after we use a floor maintainer? Do we only have to rough up the finish and clean well before applying the new? Or does the old finish have to be removed entirely? We don’t have enough fleck in our current floor. It’s supposed to be a light gray and it’s a terrible yellow. Can you please help me with the proper steps? Thanks so much!
One more question – Would it have been a better option to have used the Polyaspartic coating to begin with?
Hi Jean. As long as your current coating is sound (no peeling and adhered well), you can rough up the finish and apply a new coating or coating system over it. If the coating is not sound and shows signs of peeling or hot tire pickup, then we recommend removing the entire coating via grinding first. The reason is that the new coating is susceptible to how well the old coating is adhered. If hot tires are pulling it up or it has peeled in areas, then it’s not sound.
Assuming it’s sound, you need to rough up the current surface with 120 grit sandpaper. A floor maintainer with a 100 grit sanding screen would be easier and faster. You will go through a couple sanding screens. You can also use a green floor cleaning scrub pad instead of sanding screens. You can block sand the edges and corners. The idea is to degloss and rough up the surface, not remove it. It should look all scratched up and deglossed when done. Sweep and vacuum the surface well and then do a final wipe down with denatured alcohol applied liberally to a microfiber mop pad. This removes all the fine dust and contaminants that were missed. It dries real quick. Once dry, you can apply your new coating.
Epoxy is not U.V. stable and will eventually amber (yellow tint). In order to avoid that, you need to apply a high solids epoxy and apply the color flakes to full refusal. Color flakes are U.V. stable. Scrape off the excess flakes and lightly sand them after 10 hours or so and then apply a couple clear coats of a polyurethane, polyurea, or polyaspartic. These type of coatings are U.V. stable and will not amber. The other option if you don’t like the full flake coverage is to apply a polyurea or polyaspartic system. Polyurea is easier to apply than most polyaspartics since it has a longer pot life. We highly recommend a single-part polyurea for a DIY application.
Thank you for your clear explanation! I apologize if you received another question as on my end it didn’t appear my posts were being sent or I didn’t see them once sent.
I think a full flake coverage would be best for us moving forward. Every little scratch shows on what we have now as there are so few flakes. And the flakes will help cover the yellow we currently have.
Thank you again so much!
You are welcome, Jean. Yes, a full flake system shows the scratches much less. Just so that you are aware, the first color coat of a high solids epoxy or polyurea is going to completely cover the ambered surface and it will not show through as long as it is applied at the appropriate coverage rate and thickness. If you elect for the full flake coverage, it’s important to use and epoxy that is 85% solids or higher. Roll On Rock has a good system that you might be interested in.
Ok! It looks like I will have to order it as I’m not sure I can get that where I live. Thanks again!
Another question (When we start this project I may ask for your phone number – just kidding!)
On our floor we have one spot that has a gouge out of it from something. It’s the only spot on the floor that isn’t ‘sound’. The rest is good. Any advice on what we can do with that little area before we start? It’s about the size of my thumbnail.
Before you prep the entire floor, sand that spot with some 80 grit sandpaper including the edges and then clean it with denatured alcohol. After that, fill it to level with a little bit of the coating you plan to use.
Hi,
I am re-coating a garage I did a couple years ago with another clear coat. This garage has flakes on it and I left it rough to add more traction to the floor. What grit sandpaper would you recommend for this as I would like to keep it rough from the flakes without having to put more flakes on.
Thank you
120 grit sandpaper is what you need to use. However, a floor maintainer with a green scrub pad will actually do a better job deglossing and roughing up such a finish since it can actually follow the contours much better. Plus it will go faster.
Great, thank you so much!
Hi,
I applied a Rostoleum garage epoxy kit to my garage 7 days ago. I applied 2 coats of it. 2/3 of the garage has cured and dried fine (the middle and the part closest to the garage door). The 1/3 of the garage closest to the house still has a mild tacky feel to it (like someone earlier mentioned about feeling like tape stuck to your shoe). What I gather after reading this great article is that my next steps would be:
-sand down the 1/3 that is still tacky
-clear it with denatured alcohol
-shopvac to clean up any loose particles
-reapply a new epoxy kit to the 1/3
Does this sound correct? Thank you
Hi John. The individual steps are correct, however, you do the denatured alcohol wipe down last. The chemical wipe is what grabs any bit of loose dust and helps to degloss any small spots that may have been missed. Just keep in mind that you are going to have an overlap line where the new coat ends over the old coat. Unfortunately, epoxy and similar coatings do not blend together like paint on a wall. Unless the section you are recoating terminates at a contraction joint, you would need to coat the entire floor if you don’t want to see the overlap.
We did our garage floor 3 weeks ago and now have a small circle area that lost paint. How can we easily fix just that spot?
Hello Michelle. First, did you paint the garage floor or did you apply a coating. Also, what did you use? Paint and coating that delaminate so soon are a sign that the concrete was not prepped well enough. Was it over an area of an oil stain or some other contaminant or just a random spot?
We used the Rustoleum epoxy floor kit. Prepped with the acid, no oil spot previously, 7 yr old floor, just a random peel smaller than your fist.
OK, that helps. The reason it peeled up is because the surface profile for that spot was not sufficient for the epoxy to penetrate and adhere to the concrete. The fact that it was not an area that was previously stained with a contaminant is not a good sign for the rest of the floor either. There can be a number of reason why that area or maybe the floor does not have the correct surface profile. Did you check the concrete for a sealer before you decided to apply epoxy? Was the concrete surface troweled real smooth? Did you use the supplied citric acid etch or did you use a strong muriatic or phosphoric acid etch?
Unfortunately, Rust-Oleum does not sell touch-up kits. You will need to purchase a brand new kit to patch that small spot. What you need to do first is take a paint scraper or putty knife to the edges of the epoxy where the bare spot is. Scrape the edges good to see if they peel up or are adhered well. If they are adhered well, you will need to re-etch that area, let it dry for a day, and then you can apply new material to that spot. It will require sanding the edges of the current coating with 120 grit sandpaper where the new coating will overlap so that it adheres. If you scrape the edges of the coating where the bare area is and it begins to peel up in spots, then that is a sign that the entire coating needs to be removed as it most likely is not adhered well to the concrete due to a poor surface profile for a coating.
Hello,
Thanks for all the helpful information. I put down Epoxyshield in my garage about 15 years ago and it has generally held up well but is starting to show it’s age with some areas worn down to the concrete due to vehicles over time. We are looking to apply a new coating of Epoxyshield and are wondering if the citric acid cleaner that comes with the product along with some significant brushing when cleaning is enough to roughen up the surface for a mechanical bond? Do you still recommend sanding? Thanks!
Hi Blair. Etching solutions do not affect coatings. They have to come in contact with bare unsealed concrete in order to work. Otherwise they will just sit there and do nothing except maybe discolor some coatings a little bit. You need to rough up the surface of the current coating with 120 grit sandpaper. A quicker solution would be to use a floor maintainer with a green scrub pad. It will provide the same surface prep on the coatings as the sandpaper.