Are you planning a DIY garage floor epoxy installation? If so, consider this a “must read” if you want to avoid the most common errors that people make when applying a garage floor coating. From peeling epoxy floors to bad finishes, these 5 mistakes will cover 95% of all problems associated with either epoxy floor failure or appearance issues.
Day after day people install their own garage floor coatings and with great success. After the anticipation of creating a nicely coated garage floor however, nobody wants to go through the headaches and heartaches created when your floor doesn’t turn out like you expected.
So take a few moments to look over our list of common epoxy installation mistakes in order to insure a successful floor coating for your garage.
1. Poor floor preparation
This is the most common reason by far for epoxy floor failures and/or bad finishes. Many times when doing an epoxy garage floor coating for the first time, people underestimate how important it is to prep the concrete properly. It involves much more than making sure it is clean. Epoxy will not adhere to a smooth surface.
Not only does the surface have to be free of all oils, waxes, and other contaminants, the pores at the surface of the concrete need to be opened up properly. This usually involves acid etching at a minimum. Grinding the concrete in preparation for epoxy is even better, but it isn’t always feasible for the average homeowner. You can learn more about which method is best for you here.
The most common problem associated with poor floor prep is peeling or delamination of the epoxy.
Fisheyes is another problem. This is created by contaminants in the floor, such as grease or oil that causes the epoxy to pull away from the concrete while curing. It forms a circle in the finish resembling a fisheye.
2. Moisture in the concrete
This common mistake usually happens from not allowing the concrete to dry sufficiently after acid etching. Depending on temperature and humidity, you need to allow for a minimum of 24 hours, sometimes longer, for the concrete to dry. If not, moisture that is still trapped in the pores of the slab will rise to the surface and create bubbles in the finish.
Some water based epoxies and primers allow for application to concrete that may still be damp however. Contact the manufacturer for further information if you are unsure.
Not performing a moisture test is another mistake. Moisture under the slab can create hydrostatic pressure that will actually cause the epoxy to separate from the surface, sometimes taking pieces of concrete with it. You can avoid this problem by doing a simple moisture test first to determine if your floor is suitable or not for an epoxy coating.
3. Stretching out the epoxy
Stretching the epoxy out in order to cover the entire floor when you are running low will result in areas with a much less glossy surface and a distinct difference in color appearance. It also creates a weaker coating. This is a common mistake that is made with the single coat epoxy paint kits such as those from Rust-Oleum and Quikrete, but can also happen with premium epoxy products as well.
If you have a 400sf² garage floor for example and purchase a kit that has a coverage rate of 300-400sf², you will not have enough epoxy. A properly prepared floor is porous and will absorb some of the coating. You will run short.
Many manufacturers state in the fine print that you can expect up to a 15% material loss due to product left in the container and first coat applications. Most DIY installers are not aware of this. You can avoid this problem by making sure not to underestimate the amount of epoxy that you need.
Also, when pouring the freshly mixed batch of epoxy onto the floor or paint tray, do not scrape or try to get every last drop from the mixing container in an attempt to get the best coverage rate. The very bottom and sides of the container are never fully mixed properly. Doing so may result in spotty areas of the coating that will remain soft and not harden.
4. Faulty mixing of the epoxy
There are many problems associated with improper mixing. The most common of these issues is mixing too fast with a paddle mixer and trapping air in the epoxy. If this happens, you will get air bubbles in the surface during application. You can easily avoid this by not pumping the paddle mixer up and down or running the mixer too fast near the surface creating a vortex and sucking in air.
Other issues are not mixing the Part A resin and Part B hardener correctly or getting the ratios incorrect. Pay close attention to the mixing instructions. Some epoxies require the newly mixed batch to sit for a specific time before application. This is called induction time. If you don’t allow for this then the epoxy may not cure and harden properly.
5. Not following temperature and/or humidity restrictions
Be sure to follow the manufacturer’s recommended instructions for temperature and humidity. Epoxy applied at low temperatures or below those recommended may not cure and harden correctly.
If applying epoxy in high temperatures the pot life (time available to apply the epoxy) can be reduced by half or more. This can make the epoxy unworkable before you get it all applied as well as create bubbles from outgassing due to the warm temperatures.
High humidity levels can create a microscopic layer of moisture at the surface of the concrete that you cannot see. This will cause adhesion issues resulting in delamination or peeling of the epoxy. High humidity can cause some epoxies to blush at the surface as well.
Final thoughts
Achieving a successful floor coating isn’t that difficult. Many of these epoxy application errors can easily be avoided by thoroughly reading the manufacturer’s instructions. If ever you are in doubt, contact the manufacturer for clarification. Most problems could have been avoided this way. Also keep in mind that a bad batch of epoxy is extremely rare. The majority of problems associated with epoxy coated garage floors are due to these 5 common mistakes.
If you take the time to research your project, prepare your surface correctly, and make yourself familiar with the manufacturer’s instructions, you should be able to avoid these common mistakes and enjoy a successful garage floor coating that you can be proud of.
I applied RockSolid (Mocha) to a fresh concrete (6months old) and washed it with the etching first, using a power washer to clean off. I allowed it to dry for 48 hours then mixed the epoxy for 4 minutes by agitating bag well, and agitated before each pour.
Applied epoxy and when it dried, there was no tackiness and it dried hard, however there is black splotches along fine cracks and fish eyes and a few bubbles. pretty frustrated with the product. Ive used other epoxy coatings in the past and have never experienced anything like this.
Hi Robert. RockSolid is actually a polycuramine coating. We did a product review of it here. The biggest issue with polycuramine is that it goes on fairly thin to begin with. It’s imperative that the coverage rates be followed. The black splotches along the finer cracks is where the gray from the concrete is showing through. The coating penetrated the crack and thinned as it cured. Fisheyes are not a problem with the coating. It means there was contamination on the concrete and the coating was repelled by it. Sanding smooth the fisheyes and then applying an additional coat will take care of the color uniformity issues.
I’m painting my my garage with the rust-oleum RockSolid garage floor coating would you suggest also putting down the porous concrete floor primer ? The concrete is about 6months old (new house)
Hi Dillin. No, you do not want to use the primer unless there are issue with your concrete. Just etch the concrete with the solution applied in the kit and then apply the coating.
I need to re epoxy my floor, after 14 years. What do I need to do before this application?
Hi Cheryl. We have an article right here about that.
Hi i just purchased the rustoleum one car garage epoxy kit. I power washed, then used a degreaser, then oxyclean, then used the etch(twice) to prep the concrete. Would it be advised to use a concrete primer before applying the epoxy coatng?
Hi Wendell. No, concrete primers are acrylic latex paint products and not compatible with epoxy. They also will not adhere as well as epoxy. Your best adhesion is epoxy to bare concrete that has been prepared correctly – which it sounds like you have done.
I know that your site reccomends that you Do Not use silicone based concrete repair material to fill in cracks. Unfortunately, I don’t have the luxury of letting the epoxy or polyurethane products to cure for 7 days. Is there a downside to using silicone(cures in 2 hours), then apply the epoxy coating the next day?
Hi Wendell. There are two issues with silicone. The first is that it’s silicone – epoxy will not adhere to it. The second is that silicone crack fillers shrink over time. This will cause a hollow space under the coating that can result in the epoxy cracking if pressure is applied. Epoxy is extremely hard, but it is not flexible. Have you checked your local home improvement centers for an epxoxy or polyurea crack repair product?
Hi, unfortunately, I’ve already put the dap concrete silicone into all my cracks. Is there a way to remove the silicone so i can reapply the rustoleum concrete patch you reccomend?
Yikes… Unfortunately, it requires either the painstaking task of digging it out a little bit at a time with a screwdriver or similar. The other option is to use a small angle grinder with a crack chasing wheel. This will dig it out pretty quick and provide solid edges for the crack repair to fill to. This article has a video on how a crack chasing wheel works.
Hi, what did I do wrong my floor is peeling really bad, looks awful, been on for 4 yrs.
Hello Joanne. Unfortunately, we need much more information than that to help you out. What product was used exactly? What type of floor prep did you do? Was a moisture test performed? What does the underside of the peeled coating look like? Is it dusty with concrete or clean?
Hi, I am considering using rustoleum Rock Solid on the concrete floor of my outbuilding. I and my husband are novices at home repair, and it appears our first step is to see if our concrete is suitable. We took up carpet and linoleum from this area, and there is still a layer of old glue visible on the concrete. Very little of it is raised, it is almost all flat, but must this be removed before application of Rock Solid?
Hi Danielle. Any oils, glues, mastic, or other contaminants must be removed from the surface. In your case, the glue will act as a barrier and not allow the coating to penetrate the concrete like it is supposed to. It will not adhere well to the glue either. The best way to remove glue is via grinding the surface. There are also special Eco friendly mastic and glue solutions that you can use, but they take longer and require some elbow grease.
After finishing the garage should you use a mop and glo wax before you drive on it after it is cured. Do we need to put anything on it to keep better.
Hello Stan. Once the coating has cured completely, just use a solution of 1/4 cup ammonia to 1 gallon warm water to clean the floor. You don’t want to use anything that will leave a residue on the surface as it will get slippery when wet and attract dirt which will tone down gloss.
I had an epoxy floor installed in my basement in three different rooms. It has been just over a month and I’m seeing small oil spot coming to the surface. The prep was done properly, there were no oil stain on the floor. I’m wondering if the floor was previously painted with a oil based paint, would the oil absorbed into the concrete and that is why I’m seeing these spots?
Hi Scott. Applying coatings to basements can be tricky due to the fact that moisture can be a problem. Has the basement ever been damp from moisture before? Was a vapor barrier installed before the slab was poured? Was proper moisture testing done first to ensure that a coating could be applied? What you are most likely seeing is the result of water being pushed up through the slab to the underside of the coating and forcing its way through a small spot. This water carries a variety of substances from the minerals in the concrete. When it gets concentrated in one small area it can be dark and look oily. I would contact the company that installed the epoxy to have inspect the area to better determine what it is.
We just applied Rust-Oleum RockSolid to our garage floor in the last 24 hours and noticed some areas have a thinner layer of epoxy than other areas. Is painting over the thinner layer areas an option and if yes, what is the appropriate way of doing that to eliminate issues in the future?
Hello Char. This is a common issue with RockSolid if your concrete was fairly porous or the coverage rate was stretched. What you need to do is apply another full coat to the floor to remedy the issue. The additional coat will not get absorbed into the concrete. As long as you do not exceed the coverage rates you will get uniform color and gloss across the entire surface of the floor. RockSolid allows up to 7 days to recoat before any additional floor prep is required.
I put epoxy paint on my larder floor 2yrs ago. I decided to freshen it up and was told by my local supplier that final systems cs 10 would do. After 3 days I put water on the floor but after a week it hasn’t dried there’s still droplets on the floor, can i put epoxy paint on top?
Hello Ian. Can you provide a link to the exact product you used and what you are trying to accomplish with it?
Help! We have an epoxy floor done professionally. I wish they would have told us to pick a darker color and with more flecks. They didn’t – so now the floor has yellowed, you can see so many scratches, and it is slippery. It has been 5 years. It yellowed almost immediately. Is there anything we can do to get more flecks in it, and get rid of the yellow? Is diamond grinding the only option here?
Hi Jean. Darker colors are not good for a garage floor. They will highlight every bit of dust, foot prints, and tire prints in the garage. They never look clean accept the first day you clean it. You didn’t say what type of coating was installed, but our guess is that is was epoxy. Epoxy is not U.V. stable and will yellow with direct sunlight exposure or strong indirect U.V. light. Assuming that the coating is stable and not peeling, you can rough up the surface and apply a U.V. stable coating over it. We would recommend a single-part polyurea if you are doing it yourself. You can use an anti-slip additive for the final coat. You can rough up the surface with 120 grit sandpaper or use a floor maintainer with 100 grit sanding screens (easier and faster). We have an article here about recoating older floors.
Thank you! Sorry – yes it is a 2 part epoxy. We will try this.
Hi ,
we applied rust-oleum epoxy coating to my garage floor. Before applying the coating we did all necessary floor preparation steps and finally end result looks fine. Do we need to really apply epoxy shield on this coating. if not what will happen.
Hello Ram. Are you referring to a clear coat? EpoxyShield by Rust-Oleum makes both the color coat and clear coats.
We initially applied Rust-Oleum EpoxyShield 2 gal. Gray Garage Floor Epoxy. Now we are thinking that still we need to apply Rust- Oleum epoxy Clear finish coating . Is it required?
A clear coating for epoxy is never required, Ram, but it’s highly recommended. The clear coat will protect the color coat and color flakes. It also makes cleaning easier since the color flakes will not be collecting dirt at the edges. This article here explains more why a clear coat is recommended. If you elect to apply a clear coat, Rust-Oleum allows up to three days to recoat with another coat (clear or color). After that, you need to degloss and rough up the surface first.
Clear coat comes with anti skid additive. Still we need to perform degloss and rough up the surface?
If your current coat has been down for 3 days or less, then you can apply the clear coat directly. If it has been more than 3 days since application, then you need to degloss and rough up the surface of the current coating with 120 grit sandpaper first before applying the clear coat. It doesn’t have anything to do with the anti-slip additive. I hope that clears things up.
Can we apply clear coat on 4th day without rough the surface on epoxy paint coat?
You would need to contact Rust-Oleum customer service.
I just put a rustoleum kit on my floor and 4 days after it flaked in a few spots. I washed it and used the acid etch but I couldn’t rinse it real well because of the location. When it dried I used a good vacuum and went over the floor. I did two small rooms only one had this problem.did I do something g wrong.
Hi Rene. Concrete prep is the most important step when apply a concrete coating. If not done correctly or well enough, the coating will delaminate. More than likely the concrete was not etched adequately and/or the reside left behind from not rinsing well enough interfered with the epoxy establishing a good bond to the concrete. To fix it, you will need to remove all of the epoxy and prep the concrete again.