When to use an epoxy floor primer is a subject that is often overlooked by the average home owner who is investing in a premium garage floor coating. In fact, many people aren’t aware that they exist or think that it’s just an added cost by the manufacturer or vendor that they don’t need.
Epoxy primers provide an abundance of benefits for your coating, with some specializing in problems associated with the surface of the concrete itself. With exception to the inexpensive one-coat epoxy paint kits, if you want to insure that you achieve the best possible adhesion and endurance of your garage flooring for years to come, then you should seriously consider the use of an epoxy primer for your floor.
Benefits of an epoxy floor primer
The benefits of using an epoxy floor primer for your garage are many. Let’s take a quick look at these to get a better understanding of what they do.
- Epoxy primers are thin and provide for better adhesion because they penetrate into the concrete substrate for a better bond.
- Primers provide for a better chemical bond of the thicker epoxy base coat which results in a longer lasting and more durable garage floor coating.
- Because of their thinner nature, epoxy primers help to eliminate bubbles and pinholes that can form due to outgassing of the concrete.
- They allow for the subsequent base coat to achieve a higher dry film thickness and coating uniformity since it is not soaking into the concrete.
- Some epoxy primers are effective in providing a moisture barrier for garage floors that have light moisture problems such as efflorescence.
- Most are moisture tolerant and work well when being applied in high humidity areas of the country or concrete that has not fully dried from being cleaned or acid etched.
- Some are specialized such as oil blocking primers. These are solvent based primers made to cover concrete that has been contaminated by oil and can’t be completely cleaned.
How epoxy primers work
Epoxy adheres to concrete by forming a mechanical bond within the pores of the surface. This is why you need to profile the surface by either etching or grinding the concrete.
Primers are designed to penetrate deeper into the pores in order to achieve a better mechanical bond. This reduces any chances of delamination of a properly prepared surface. The primer also produces a thinner epoxy film or tie coat that the much thicker base coat can chemically fuse with. This process produces a much stronger bond of the base coat and is why most contractors always use a primer.
Air bubbles, craters, and pinholes can be created in epoxy from outgassing of the concrete. Air in the slab will rise due to a temperature increase or change in humidity. If this happens during the initial application and curing process of a high solids or 100% solids epoxy to bare concrete, it can form these bubbles, craters, or pinholes when the air escapes the concrete.
As a side note, these bubbles can also happen due to poor mixing of the epoxy or improper back rolling.
Because of their thinner film, epoxy primers reduce the likelihood of bubbles and pinholes forming. They do this as they soak farther down into the concrete to fill the voids that can hold air and reduce the chances of air finding its way to the surface. If air does find it’s way to the surface, the bubble will usually pop and then slowly fill back in before curing due to the low viscosity of the epoxy primer.
Since most epoxy primers are water based, the chemical makeup provides for moisture tolerance as well. As a result, some brands can actually be applied to a damp slab. This is beneficial for the DIY epoxy installation that profiles the slab with acid etching. Instead of waiting 24 -48 hours or more for the slab to dry completely, you can apply your primer when the concrete is still damp or if the humidity is up.
Many of these same primers will also form a vapor barrier to ward off the problems associated with moisture that tries to work its way to the surface. If you think you have a moisture problem, contact the manufacturer first to determine how much moisture you can have in order to use their product.
Oil stop epoxy primers
Finally there is epoxy primer for those who thought they could not epoxy coat their garage because of oil contamination that could not be removed completely. Some manufacturers make an oil stop primer that is solvent based and works by actively seeking out and bonding to the oil contaminants embedded in the concrete.
These are usually dark in color, however, and need to be covered with more than one base color coat or with a full refusal paint chip application. If not, the darker color may bleed through and alter the color coat.
Will your epoxy floor coating fail without a primer? No, if you prepped your floor correctly, chances are your coating will not fail. However, with all the benefits that can be gained from using an epoxy floor primer, it’s hard to come up with an excuse not to. They are definitely something to strongly consider and most cost less than the high solids epoxy formulas due to their thinner film thickness.
If you are going to spend the money for a commercial quality, high solids garage floor coating, then it’s well worth the few dollars more for an epoxy primer. It will help to provide the most durable and trouble free coating that you can have for your garage and the investment will provide a great return for years to come.
*** Update ***
We have been receiving numerous questions regarding the use of an epoxy primer for the single coat DIY garage floor kits that you can find at most home improvement centers. Some of these include but are not limited to, Rust-Oleum EpoxyShield, Valspar, Quikrete, and RockSolid floor coatings.
With the exception to RockSolid, these kits are low solids epoxy with a low viscosity. In other words, they are a thinner coating. They do a good job of penetrating the concrete already. While RockSolid is a higher solids coating with a higher viscosity than some other DIY epoxy kits, the Polycuramine formula does an excellent job of penetrating the concrete like the other brands.
While epoxy primers are typically a lower solids water based coating, they cost just as much or more than the typical DIY single coat kits and they are of a higher quality. The performance and durability of the typical epoxy primer is better than most of the DIY home improvement garage floor kits as well.
If you are concerned about the benefits of a primer, you are much better off applying two coats of the DIY kits versus one coat. The second coat will allow for a thicker coating with much better color uniformity. It will also provide the opportunity to cover any cosmetic defects in the first coat that can be caused from environmental conditions in the substrate and application errors.
Grant says
Would you still suggest a primer on a garage floor with a polyaspartic epoxy and a really good profile?
Shea says
Hello Grant. If you have a very good profile that was achieved by grinding, then most polyaspartics do not require a primer. However, always check with the manufacturer. Some applications may require thinning of the first coat and this acts as a primer.
Grants Painting says
Im not sure I understand. Why does it matter if its a grinder or acid etch?
Shea says
We’re not quite sure that we understand your question. You can use an epoxy primer on concrete that has been profiled by grinding or by acid etch. Please feel free to elaborate if you like.
miguel says
Are there any epoxies that don’t need primer?
Shea says
Hello Miguel. Epoxies do not “require” a primer to work. However, a primer is a wise choice to use for all the reasons mentioned above and is also why professional installers use primer. They can’t afford to put down a coating that they might need to come back and repair at a later date, so they insure the quality of their coating by using it. You can install most epoxies without a primer and have good results if you have prepped the floor properly, but you will not benefit from the additional gains that a primer will provide.
Jeromy says
For a basement, should I use water based or 100% solid epoxy? Should I use a primer? If so what kind? I’ve decided on Armorpoxy, Armorgarage, or Budget Bob’s as my 3 possible companies I will order from. I would like this floor to be my permanent floor. Any suggestions? I’ve just heard that Rustoleum Epoxyshield (even the Professional kit) is not very good durability.
Shea says
Hello Jeromy and thanks for visiting our site. Your question depends on how durable you want your floor to be. If you are looking for a high build coating that will give you the best protection for the dollar, then 100% solids epoxy is the way to go. Many manufacturer’s will use a water based primer however since it is not being used as the build coat. Both ArmorPoxy (which goes by ArmorClad for their residential products) and Armor Garage sell and recommend using a primer. Budget Bob’s does as well. ArmorPoxy and Armor Garage provide very good products. Budget Bob’s product changed after his death a few years ago. They do not provide technical data sheets online to compare, so we don’t have an opinion about their product.
For long term wear, the EpoxyShield kits are not your best bet. The Professional series is better, but it is solvent based and you don’t want to be applying that in an enclosed area of the home. Also if you haven’t done so already, make sure to do a moisture test first since it will be applied in a basement.
Nick says
Hi I had a couple of questions. I have spoken with three different professional installers, all touting what they apply as best which is making it difficult. However when discussing application, none of them mentioned a primer. All stated basically grind (or shop blast?)\clean, apply color coat , chips, top coat. When asked what about a primer coat the basic response was oh, the product mfg has that all figured out in the product itself.
That sound odd to you? I want the longest lasting floor possible and I’d think they would not want warranty issues so why would they all skip the primer step? (BTW my garage floor 1 approx 1k sqft and about 10 yrs old w typicla dirt\stains if it matters).
Regards,
Nick
Shea says
Nick, you’ve been asking about both polyaspartic/polyurea coatings (PAP) and epoxy coating in different articles on our site. It’s not unusual for professional installers of PAP systems to not use a primer. PAP coatings are typically thinner than commercial epoxy, the base coat can be made less viscous for better penetration, and due to the fast cure rate, vapor transmission doesn’t have much of a chance to form bubbles.
For epoxy some installers will thin the first coat of commercial epoxy which will act as the primer. Others may state what you cited about the manufacturer stating that it’s all figured into the formula. That, in our honest opinion, is just good marketing tactics by the manufacturer in order to try and make their product look better. It is not a substitute for primer though. As we stated in the article, no epoxy manufacturer states that you have to use a primer. However, many good installers use them for the reasons stated above. If you feel confident in the work of the installer, if they were willing to offer references, and they have a good warranty and are known for standing behind their work then I wouldn’t worry too much.
Nico says
With the 1 coat epoxy systems, can I apply a primer to make the system more durable or does it do more harm than good?
Shea says
Hi Nico, applying an epoxy primer first will always improve the performance of a quality epoxy product. It allows for a thicker dry film thickness of the base coat since it won’t be absorbed by the concrete and better adhesion as well. Technically you would have a 2 coat system this way.
jared says
Hi, I am wondering if I can use epoxy /epoxy primer on a freshly poured garage floor or would this not allow the concrete to cure properly. Essentially what I’m looking for is a glossy looking floor that I can spill oil on and just wipe it off, also what could I put on it to make slip resistant?
Thanks
Jared
Shea says
Hi Jared. You need to wait a minimum of 28 days, preferably longer if you can, before applying epoxy or most any topical film forming sealer to a freshly poured garage floor. Moisture is being released during the curing phase and will interfere with the adhesion process. After that you will need to acid etch or grind it in order to apply the epoxy. One coat of primer by itself is not recommended. Primers are designed to penetrate the concrete and can leave a blotchy look. If you apply a second coat of epoxy or polyurethane over the primer, then you will get the glossy look. Polyurethane is the best for adding an anti-slip additive like Shark Grip. It will make the floor slip resistant.
Greg Trelfa says
i coated my shop floor 15 yrs. ago with Rustoleum Professional Floor Epoxy. It has lasted very well but it’s time to be repainted. What steps should I take to ensure a quality job?
Shea says
It all depends on the shape of the current epoxy Greg. If it is only worn in a few places, looks dull, but adhered well and not peeling up, you can always recoat it. We talk about that here. If it’s too worn out you will need to grind the floorto remove the existing coating in preparation for new epoxy. We have many articles with tips on applying epoxy, plus a DIY epoxy installation guide. You can find them here.
Roy Foreman says
I have a clean but dimpled concrete garage floor. I do not like the thought of grinding or using acid. Can I produce a sound finish by simply coating the rough concrete with a couple of coats of good primer prior to adding the paint surface. The garage houses one car and is lightly used. Thanks
Shea says
Hi Roy. Assuming you are wanting to apply a 2-part resinous coating such as epoxy and not just paint, you are required to acid etch or grind the concrete first or it will not bond to the concrete correctly. A primer is not a substitute for proper concrete prep. It has the same requirements of the concrete before application. If you want to review a product that does not require acid etching or grinding of the concrete, we recommend that take a look at Rust Bullet concrete coating. However, you still will have the issues of the dimples.
Leisa says
I love your forums!! For a DIY person, they are extremely informative and very helpful!
I purchased Armor Garage’s Armor Chip Garage 100% solids epoxy flooring. I didn’t buy their primer because they told me that it was not necessary. I have read a lot of online forums and get mixed responses about this, for the reasons that you have outlined above. While acid etching my garage floor, I could see very tiny bubbles coming up through some of the cracks. While I am planning to fill all of the cracks that I can see with SIka Crack Filler (followed by sanding), I am worried that there might be some micro-cracks that I missed and which may be a source of rising air bubbles. I am thinking that a primer would help address this concern. It will take me a week to order & receive their primer and I am wondering if I can just go to the local Sherwin Williams commercial store near me and use one of their Armor Seal Epoxy Primers so that I can apply it tomorrow. They have a 100% solids epoxy primer/sealer as well as two different water-based epoxy primers, and can be found here:
http://www.sherwin-williams.com/search/?siteSection=painting-contractors&Ntt=epoxy+primer
Questions:
1. In reading all of your extremely helpful and well-written forums, am I correct in assuming that I could use one of these as a primer or will there be some type of compatibility issue with Armor Garage’s epoxy base coat? I don’t understand why there would be compatibility issues but the SW customer service guy said you could only use products within the same line. I am assuming they are saying this more for liability reasons rather than technical reasons but am not sure. Is that assumption correct?
2. If I can use the SW primer, can I go with the water-based epoxy primer or does it have to be 100% solids to match the 100% solids base coat?
3. And if I can go with water-based epoxy primer, which I am thinking I can based upon what I have read on your website, is one of these 2 products better for me to use: ArmorSeal® Floor-Plex™ 7100 Water Based Epoxy Primer vs. ArmorSeal® Water Based Epoxy Primer, and if so why? Just trying to learn here. 🙂
It’s a Saturday and I would like to try and buy this today so that I can apply tomorrow. I’m not sure if you’re checking this forum, but any insight/help that you can offer me would be greatly appreciated!! Thank you in advance.
Shea says
Hi Leisa and thanks for the kudos. There should not be a compatibility issue with using a different vendor’s epoxy primer, especially water based. That said, it could effect how Armor Garage would react if there is a problem with your coating. We know that Armor Garage sells very high quality product. Unfortunately however, they are one of the few vendors who do not make their TDS sheets readily available. As a result, we can’t determine which SW primer most closely resembles what Armor Garage offers.
If you want to put down an SW primer anyhow, you do not need the high build 100% solids. The Armor Garage base color coat is already a high build coat. You would be better off with the higher solids water based primer.
Do not worry about your micro cracks. The primer coat will take care of those if you choose to use it as will the Armor Garage high build color coat by itself. The key is to apply the first coat after the temps have peaked and started to cool. This significantly reduces any chances of water vapor wanting to rise up through the slab into the epoxy. The bubbles you saw coming up while etching is perfectly normal. Just make sure your floor is bone dry before applying the epoxy.
Also, make sure your crack filler is sandable. Many have made the mistake of purchasing SikaFlex self-leveling crack sealer which is not. It’s also not paintable.
Leisa says
Thank you, Shea, for the fast response! 🙂
The Sika product I am using is 100% solids and non-self-leveling. http://www.homedepot.com/p/Sikadur-6-fl-oz-Structural-Epoxy-Crack-Fix-107655/204732364
And I’ll definitely apply the first coat once the temps have started declining – great tip. 🙂
Can you recommend a good higher solids water based primer?
Thanks again!
Shea says
We can’t recommend a primer that you can buy locally. With few exceptions, most all quality garage floor coating products need to be ordered. If you are going to order then it would be best to go with what Armor Garage has. The epoxy crack product that you linked to will work just fine.
Elias says
Hi!
Great information on this site! It’s a great resource!!
Is there a preferred primer you could recommend for use with the epoxymaster kit? Would something like a SW armorseal 33 be worth it/overkill?
Thanks!
Shea says
Hi Elias. Yes the Sherwin Williams Armorseal 33 is overkill. Plus, it’s fast cure with a very short pot life that requires experience to get down fast. Garage Flooring LLC has their TrueLock TL015 water based primer that will work real well with the EpoxyMaster kit.
Elias says
It turns out we have some armorseal water-based epoxy primer (7100) left from another job. Any technical reason this wouldn’t work?
Thanks!
Shea says
It will work Elias. It’s a very low solids (38%) water based primer, so it won’t pretty when it goes down. Don’t be alarmed with a patchy look when using a primer as it soaks in more in some areas due to the density and porosity of the concrete. It will all be covered up with the EpoxyMaster color coat however and look very nice.
Leisa says
Hello again!
I ended up not using a primer and just used the Armor Garage 100% solids epoxy base coat. It was also a squelcher of a day here, which is unusual for my marina, so we waited until after 6 pm (when the temp started declining) to apply it as per your recommendation. And everything has gone smoothly so far. 🙂
I am now going to apply two coats of their polyurethane topcoat.
Question – Do I similarly need to wait to apply the polyurethane until this evening when the temperatures are dropping? I’m thinking not, but just wanted to double check as the temps are supposed to be unusually hot the rest of this week.
Thanks again – you rock!
Leisa
Shea says
Good job Leisa! No, temperatures dropping is not as important with the polyurethane when applying it over another coating. Pay attention to the temperature and humidity restrictions of the polyurethane however. Tip – Don’t apply it too fast or too thick or you can introduce bubbles.
Leisa says
Thanks!
One last question – I put the firs layer of Armor Garage’s provided topcoat on last night and I tried my very best to make sure I rolled over every spot, which was kind of difficult given that I had spread paint chips to full refusal. They provided me with one gallon and I used half for the first layer as per their instructions. This morning after it is dried, I can tell that it was not evenly distributed. I called them and they said that it shouldn’t matter and that I will get full coverage after applying the 2nd layer.
I’m a bit concerned though and asked them to clarify if it was urethane or polyurethane. They said it was urethane. If after the 2nd layer of top coat has dried and I still see inconsistent coverage, can you recommend a urethane topcoat that I could buy today? To get more through them will take over a week, time which I don’t have as I need to start moving things back into my garage in the next 2-3 days.
Thanks again for all of your help & tips – it is very much appreciated!
Leisa
Shea says
Leisa, the term “urethane” is commonly used as a shortened version of the word “polyurethane”. Technically there is no such thing as a urethane concrete floor coating, but it’s an industry accepted word that the public is familiar with. What you are using is polyurethane.
What you are seeing after your first coat with color flakes to full refusal is completely normal. Polyurethane goes on thin so the first coat is going to look patchy. The second coat does a much better job at filling everything in. If the color flakes were not scraped down real well, it may require an additional coat or two afterword’s if you are trying to accomplish a completely smooth finish with no texture.
The Armor Garage polyurethane is a very high quality product and at this point it’s not a good idea to introduce a different manufacturer’s product. Most commercial product like this has to be ordered. If you feel that you will need another application, don’t fret. Order some more while the floor cures. Once it has cured, sand the finish with 100 grit sandpaper to remove the gloss, vacuum, and then wipe it down with denatured alcohol applied liberally to a towel. After that you can start applying more coats.
Marc-André says
Hi,
I’ve been reading your site for a while now its very useful thank you very much. So i’m from Canada and many of the product you recommend aren’t available up here. So i’m using ctm 100% solid epoxy and i was wondering about the primer because the sale rep didnt seem to think it was necessery. So is this product: http://www.surf-pro.ca/english/concrete.html could be a primer or its just a replacement for muriatic acid?
Thanks
Shea says
Hello Marc-André. That product is just a mild eco friendly concrete etching product. It is applied to concrete to provide a mild etch for paint and is not nearly strong enough to prep concrete properly for 100% solids epoxy.
Hopefully you are not getting confused about epoxy primers due to this product. An epoxy primer is a 2-Part resinous epoxy that is usually water based. It is applied to a properly prepared concrete surface. You should acid etch at a minimum to properly prepare the surface. Grinding is even better. We talk about the differences here.
100% solids epoxy does not require an epoxy primer, but it is recommended in order to get the best adhesion and smooth looking surface without cosmetic defects. If you are trying to source an epoxy primer, check out Legacy Industrial. They ship to Canada and can answer any questions you have about their primer products.
Marc-André says
I was actually confused because they advertise it as a concrete primer that help epoxy to stick…. I’m forced to grind because a sealer is present on the concrete. So my planning, thanks to your site, is: Clean with t.s.p, wet grind with diamabrush (they have it up here at home depot too), then clean again with t.s.p, then repair, then coat. Sounds good?
One more thing about the coating, my garage is 262 sq feet and the sale rep said i should put 2 kit in one big coat (i kit is 250 sq feet). So 1 kit for half the garage then another kit for the rest. Is that correct? Or should i do 2 coat?
Last question. In one of your article you talk about polyurethane clear top coating, so could i use a rock solid polycuramine clear top on my 100% epoxy to protect it from uv?
Thanks a lot!
Shea says
Clean the floor first then do your repairs. Grind after that making sure you clean the floor well afterwards. Apply one coat first, let it cure for the required amount of time (10 – 24 hours) then apply the second coat. The larger your batch of 100% epoxy the shorter the pot life. If you were to mix both kits together and apply in one thick coat you would have much less time to get it down. Plus, the second coat helps to cover any mistakes you might have made with the first.
RockSolid polycuramine is a blend that includes polyurethane and is not U.V. resistant. We recommend using a standard polyurethane clear instead.
Martin says
What is a good low cost epoxy primer to use with Epoxy-Coat?
Shea says
Hi Martin. Garage Flooring LLC offers a good water based epoxy primer called TrueLock TL015. You can find it here near the bottom of the page. It will work great with Epoxy-Coat.
Martin says
Thanks! I was considering using Nohr-S as a clear coat, and LI has a Standard Epoxy Primer/Coating. Would it work as well? It appears the cost is about the same either way.
Or I could get the TL015 and use clear Rust Bullet for the clear coat. The Rust Bullet is less expensive than the Nohr-S.
My main concern is yellowing of the blue Epoxy-Coat since I have 8 large clear polycarbonate skylights in the roof of the building. Which will do a better job of protecting the epoxy, the Rust Bullet or the Nohr-S?
Shea says
We forgot about the Legacy Industrial primer. It’s an excellent product as well and they endorse using it for Epoxy-Coat. The Nohr-S would be a great choice for a top coat. The Rust-Bullet Clear Shot is not designed to be used with other products.
Martin says
I spoke with Justin at Garage Flooring earlier, and he suggested using the Rust Bullet clear coat over the Epoxy-Coat?
Shea says
I believe that would be after the Epoxy-Coat has cured first and then sanded to accept the Rust Bullet. He would definitely know the details on that however.
Martin says
No, he actually said to apply it within 10-24 hours of the Epoxy-Coat.
Shea says
Ok, excellent then! That’s one bit of info we hadn’t acquired.
Brad G says
Thanks for the great technical reviews and your active response to questions. As an engineer i really struggle getting past all the marketing b.s. to figure out the true performance, requirements and compatibility of products.
What is a good primer for the Rustoleum Rocksolid polycuramine? Is their Moisture Stop a good product?
With regard to the concerns of the yellowing of the Rocksolid polycuramine, what is a good clear coat for a New England full-season car garage (tools, hot tires, melting snow with salt)?
Shea says
Hello Brad and thanks for the comments. The RockSolid polycuramine does not need a primer. Because of it’s unique blend, it penetrates into the concrete very well for the first coat. That is why some people are having issues with patchy looking floors. If the floor is prepped well, the RockSolid soaks into the concrete well for a good bond, but because it goes on so thin, you can have patchy looking areas of less gloss and color. It ends up looking like a primer coat should and not like a final color coat. That is why some people are having to recoat with a second color coat.
The moisture stop is really just that – a penetrating sealer that helps with moisture. It doesn’t actually provide a better bond or act as a primer for the RockSolid. It’s of our personal opinion that it’s not necessary. If you have moisture issues, the floor should be tested first anyway before going with a topical coating of any kind.
As far as clear coats go, a polyurethane or a polyurea clear will have 100% U.V. stability, including much greater abrasion resistance and chemical resistance. They are good for your New England weather. It will slow down the ambering process of the RockSolid greatly, but it won’t stop it.
We suggest you read our article on Legacy Industrials new Nohr-S product Brad. You can find it here. It is a 100% U.V. stable product that provides much better protection than RockSolid. While RockSolid is a good DIY product for someone looking for decent protection of their garage floor, the Nohr-S product is a true commercial quality coating. Once you add up the cost of 2 coats of RockSolid plus a coat or two of clear, you may not be far off from the costs of a Nohr-S coating.
sderavc says
Nice
Tony says
What is a good primer to use with Armorclad’s epoxy kit? Anything I can use from SWP?
Thanks!!!
Shea says
Hi Tony. Armorclad has their own epoxy which you can find here. It’s always best to stick with the same manufacturer when you can.
Jason says
Can a cheap single coat epoxy be subsidized for a epoxy primer? Would that be benifical or could it cause problems with your top layer?
Shea says
Hi Jason. Technically, a cheap water based epoxy could work as a primer, but it does not have the same adhesion characteristics of a quality epoxy primer. You may be surprised to learn that quality epoxy primers designed to work with high solids epoxy systems are about the same cost or a few dollars more than the cheap epoxy you can by at home improvement centers.
edgar says
Why the epoxy is looks like sponge when is dry in the recipient?
Shea says
Hello Edgar. That is a common look with epoxy primers. The primer coat is sometimes referred to as the ugly coat. It seeps into the concrete more in some areas than the other which creates that look. When the base color coat is applied, you get a nice consistent color and coverage rate because the color coat is not being absorbed by the concrete.
Marie says
Looking for a good primer for Rust-Oleums Profesional epoxy floor coating. I am thinking a primer, the two coats of color, then two of clear coat but cannot find any information about a primer recommendation specific to Rustoleum professional. Looking on August, there are a couple of clear primers but the best (which looks like a commercial product) will cost more than all the coats of colored and clear epoxy combined. Would I be better off going with the commercial primer or with a thinned coat of the colored epoxy coating? I realize that at this point I could have just gone with a higher quality system, but I have everything but primer now. I prefer to stay with the same manufacturer for the entire project.
I am a complete and total novice, but I would like to do this project as well as i can. Any suggestions would be greatly appreciated!
Shea says
Hi Marie. The reason you can’t find an epoxy primer for the Rust-Oleum Professional is because there is none. Most actual epoxy primers cost more and perform better than the Rust-Oleum product. They are manufactured to penetrate the concrete and provide excellent adhesion for high solids commercial quality coatings. Rust-Oleum Professional is not considered a commercial quality epoxy, despite its name. It is a better quality DIY epoxy, however, than many of the water based DIY epoxies available. It is a solvent based epoxy that is a lower solids, like most epoxy primers are, and will penetrate and adhere to properly prepared concrete just fine. The first coat will act just like a primer and your second coat will do a great job of providing color uniformity and a higher spread rate.
The most important job is preparing the concrete surface correctly. Most people who have done good preparation and used the Rust-Oleum Professional have been very happy with the performance of the product.
Kenny says
Hello. I work in a floor Company and were starting to make epoxy floors.
My problem is that we use some flow concrete first in light grey and grind it and when we apply the epoxy the floor gets almost brown and stats that way. Its like when you get the concrete wet with water but that dryes up and get light Grey again and with epoxy it Does not. The problem is that if the customer wants a gray floor with a clear top coat and after the epoxy it gers almost dark brown.
Kenny.
Shea says
What are you using exactly when you refer to “flow concrete” Kenny and why are you using it? Also, what type of epoxy are you applying?
ryan in charlotte says
Hi – I live in a house built in the 1940’s and I have an unfinished (unpainted/unsealed) concert basement floor. I don’t know how old the concrete is, but it is a little rough. I want to seal/paint it primarily to act as a moisture barrier and water vapor. The basement will never be used for anything other than storage. And I wouldn’t mind brightening the place up with some color. During heavy, heavy rains, I will get some moisture issues where the brick wall meets the concrete floor. We got a torrential rain the other day and I did the moisture test (square plastic) and I am not surprised, but it failed.
Does this mean I am out of luck, or can I use an epoxy sealer/primer (ideally followed by a paint/epoxy for the color). Any advice or product recommendations would be appreciated.
And if you think this is beyond a DYI project, please let me know.
Thanks! Ryan
Shea says
Hello Ryan. All moisture will need to to be blocked first before applying any type of paint or epoxy. The hydrostatic pressure from the moisture on a below grade slab will cause the epoxy to lift, possibly taking chunks of concrete with it. There are special vapor barrier, moisture blocking epoxy primers, but they are expensive. Plus, you will need to moisture test the slab first (calcium chloride) to determine how much moisture vapor transmission you have in order to determine if it is within limits. Your basement may not be the best candidate.
We recommend that you make sure you have the best drainage possible away from the house and then apply a penetrating sealer to the slab and walls of the basement. RadonSeal is a popular product for basements. After 30 days, do another moisture test during wet weather and see how you do. If it comes out negative, then you should be OK for some concrete paint on the floor.
ryan in charlotte says
Shea – thank you for the response, I appreciate it. I don’t mind spending a little more money on a quality epoxy primer or testing the slab first using the calcium chloride route. If there is a product, or a text kit, that you would recommend, I would appreciate it.
If I want to go the Radon Seal route (I have read a fair amount about it). do I need to moisture test before applying?
I am more concerned with the vapor/moisture barrier qualities than the aesthetic quality, so painting is not absolutely necessary.
I should add that one other product I have considered using is Hydro Seal 75 by Northern Industries. Let me know if you have any thoughts on that product. I’ve read mixed reviews on Radon Seal (although many are about its effectiveness re radon reduction which isn’t my concern).
To be honest, the wide variety of products, types, etc, gets to be a bit overwhelming. Thanks again.
Shea says
Just google “calcium chloride test kit” and you will find many examples. They all work the same. Once you get the results you will have a better idea of the amount MVT’s you have and what your options may be. We are not familiar with Hydro Seal 75, but once you have the results of the moisture test you should contact them to discuss it if that product interests you. They should be able to tell you if it will work or not. We don’t specialize in information for stopping moisture intrusion in basements, but we do know that it is not always a sure thing. The most important part is knowing how much moisture you are dealing with, particularly if you are dealing with a coating. Sometimes penetrating sealers may not completely stop moisture intrusion, but they reduce it quite significantly.
ryan says
Thanks Shea, I appreciate it. The moisture issue is really not that significant – I’ve had a number of basement guys look at it and they don’t recommend much beyond keeping the draining good and my gutters clean (I dropped the ball on the gutters during our latest rain storm). No need for a sump pump, etc. But I am going to do the calcium chloride test. I am also going to give Legacy Industrial a call as well. Thanks again for the info.
Amy says
We have a Rust-Oleum professional 2.5 car garage kit that we are using on our garage floor. I am so sorry but I am a little confused from reading some of this article if I should use a primer before the base coat? Also, I have some basic cracks throughout the floor from when it was laid a year ago. Can I use this product for example, http://www.homedepot.com/p/Sikadur-6-fl-oz-Structural-Epoxy-Crack-Fix-107655/204732364 to fill the cracks and then I sand them? Im guessing I would etch the ground first, once its prepped, fill cracks, sand them, then lay the primer, and then lay the epoxy kit?
Would you mind doing me the biggest favoring and confirming for me if that sounds right? I would appreciate it soo soo much! Thanks!!!!
Shea says
Hi Amy. Your project order is correct, however, you don’t need the primer. Epoxy primers should be used in conjunction with high solids, commercial quality epoxy to insure the best performance for these high quality coatings. The reason for this is due to the high solids content that can create some issues when applied to bare concrete. The Rust-Oleum Professional is a lower solids DIY kit that does not require nor need a primer. It’s a better kit, however, than the water based EpoxyShield kits. Because it’s a lower solids epoxy and solvent based as well, it does a good job of penetrating the concrete to form a good mechanical bond.
The Sika Epoxy Crack Fix will work just fine for repairing your cracks. If they are very wide or deep, you may want to fill the crack part way with silica sand before applying the epoxy. Because the SikaFlex is a low viscosity epoxy, the sand will keep it from draining down real deep, requiring you to use much more than is necessary.
Quan says
Learned a lot from your articles and many thanks. If I choose solvent based rustoleum product(epoxyshield professional), since there is no primer for this product, for a better outcome, should I go with two coats of the epoxyshield product, then add one coat of clear epoxy (from rustoleum as well)?
Thanks a lot!
Quan
Shea says
Yes, that would work well Quan.
Quan says
Shea,
Thanks for the quick response. Any suggestions about the time between two coats of epoxy application, and the time between main color epoxy and the clear coat?
Quan
Shea says
According to Rust-Oleum, you need to to wait 10-12 hours between recoats. The general rule is if you can press your thumb to the epoxy without leaving a print, it is ready to go.
Scott Eaton says
Shea,
I’m considering using the Oil Block Primer for Oil Stained Floors (TL820 from Garage Floor LLC), before I use two coats of Epoxy-Coat. I’ve cleaned and degreased the Garage Floor several times, and etched the floor with Muratic Acid (strong concentration) at least twice. I have two questions. First, some of the oil is Chain saw bar oil that I’ve tried everything on (except the Kerosene and Portland Cement you spoke about). I’ve even used a hand grinder on those spots and then degreased them again (with your recommendations for difficult oil stains that have been there for many years). Still, the water beads up. The other areas (with no visible oil stains) might not be auto oil or chain saw bar oil, but when I drop little beads of water on them the water does not sink into the concrete, or if it does some of the areas take the water beads over an hour to sink in (this is probably on one third of my 450 sq foot garage floor). Will the Oil Block Primer be effective in these areas too? (in other words, what is included in the category of Oil – other than regular car oil and Chainsaw bar oil?) The garage floor is over 25 years old so I’m not sure what is causing the water to bead up (likely something from a car engine, or something that would come from under a car or tires?).
The other part of the question is – for the part of the Garage floor that does soak up drops of water quickly (which is good), is it still okay to apply the Oil Block Primer there too – Or should I use their regular Primer that you recommend (TrueLock 1 Gallon WB Primer TL015 Covers 229 – 320 Sq. Ft. — CLEAR) in those areas?
Shea says
Hello Scott, what percentage of the floor absorbs water as compared to the part that does not? Also, are the areas that don’t have oil stains but still don’t absorb water located in one general area or are they randomly spaced? Was the floor tested for a sealer before you applied the muriatic acid?
Scott says
Thanks for your quick response Shea. I did not test for a Sealer. I did spend quite a bit of time (today) putting water droplets on the floor every couple of inches to be sure where the floor was soaking up water. Over the Chain Saw oil stains, the water drops never go away (until they evaporate). There are 6 of those stains about 6 inches in diameter each. In addition to those spots, there is about one fourth of my garage floor where the water drops tend to bead up and then eventually (20-40 minutes later) they finally get absorbed into the concrete. This 1/4 of the floor where water doesn’t absorb into the concrete right way are scattered around, but tend to be where the cars get parked (for the last 27 years). With the other 3/4 of the garage the water drops absorb into the concrete right away or at least within the first minute. I used a 4.5 inch Angle Grinder with Diamond Cup Wheel over the Chain Saw oil spots but that didn’t help (it actually made the floor smother, so maybe the Ridgid 4 inch Diamond Cup Wheel wasn’t the right choice.
Update – Shea – I just found from some old paper work from when the house was built that might help (I’m the second owner). This might pertain to the driveway (instead of the garage not sure), but reads, “…..we utilize a clear sealer/hardener on all surfaces taking vehicle traffic. The “curing compound” is sprayed on at the time your concrete is placed slowing the natural curing process and maximizing strength and resilience.”
Shea says
The old paperwork you found Scott supports why I was asking these questions. What was applied to the concrete years ago was a “cure and seal” agent that helps the concrete to cure more evenly without problems. It also seals the surface. Over the years, they can wear away some in places – usually where the most traffic occurs, but not always. This explains why you have some areas absorbing water and other areas that don’t (with exception to the oil stains). Acid does not work on sealed concrete. What you need to do is properly grind the entire floor to get the profile you need. Once you do that, you can then re-evaluate the stains and make a determination on whether or not you will need an oil stop primer. I know it’s not what you wanted to hear, but it explains the issues you are having with the floor.
Scott says
Thanks Shea. I’ll rent the Floor Polisher with the Diamabrush attachment from Home Depot tomorrow and grind the whole floor. I’ll do it wet to avoid the dust and follow your instructions by using the Wet/Dry vac to suck up most of the slurry before hosing it out of the garage .
Scott says
Shea – I rented a Floor Polisher form Home Depot, with the Diamabrush attachment and did the garage floor last night. Some of the areas are better but more than half still don’t totally absorb the water drops (within 5-10 minutes). When the water drop is first places on the garage floor the concrete turns dark and the water drop spreads out to at least twice the size it was when it landed on the floor (within a second or two) but then, in the right light, 15-20 minutes later, you can see that the water is still there, sitting on top (vs. the entire water droplet being absorbed by the concrete within the first 10 seconds). These are locations where there is no visible oil stain.
In two of the areas, which didn’t appear to have any stains, but had previously had problems with water absorption, I grinded that a second time (this time with my 4.5 inch angle grinder with the Diambrush attachment) and then applied the water drops again, and over an hour later, you can still see most of the water droplets on the surface.
I guess my question is – what is the longest period of time the water droplets should take to absorb totally into the concrete? For example, if it takes 30 minutes – is that a problem when it comes to Epoxy? Does this mean I have to use an Epoxy Primer, and if so does it need to be an Oil Block Primer?
Shea says
If the concrete immediately turns dark and the water droplet expands in size, then the surface is good Scott. Remember, concrete is like a sponge. When a drop of water is placed on a sponge, it immediately spreads in size while the sponge remains damp. It takes a while for evaporation and water vapor to escape allowing it to dry. If the water droplets remain in the same round form and do not turn the concrete dark immediately, then you still have an issue. Check out this post for a better explanation. The video should help as well. How has the water reacted with the chain saw oil stains?