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Polyurethane versus Epoxy Coatings for Your Garage

polyurethane vs epoxy

The subject of a polyurethane or epoxy coating for a garage floor eventually comes up when deciding on what materials to use for your project.  Admittedly, it can become a bit confusing when asking around or researching which floor coating is best to use.  Epoxy and polyurethane are great for protecting your floor against stains, damage, chemicals, oils, and wear.  They are both light reflective, easy to clean, and long lasting.  They also have their own advantages depending on the application.  So which one should you use and what is the difference?  Well, the short answer for most applications is to use both.  Let’s see why.

Epoxy Floor Coating Benefits

Epoxy is a thermosetting polymer which is available in three different formulations for a garage floor coating and sealer; water based, solvent based, and 100% solids.  These formulations allow for varying degrees of thickness from 3 mils to over 10 mils for a single coating for a garage floor.  They also allow for ease of application, special bonding characteristics, and VOC considerations.  Epoxy bonds extremely well to properly prepared concrete and can sometimes be used as a resurfacing agent for old or worn concrete that need a new garage floor surface.

The best epoxy formulations are 100% solids and provide for an extremely hard, thick, and impact resistant surface.  This self-leveling thickness contributes to filling in the small hairline cracks and imperfections of the floor as well as providing protection.  It also works well against hot tire pick up, scratching, and wear from abrasion.  Though some epoxy formulas come with U.V. inhibitors, they will still eventually yellow or amber as the industry calls it when exposed to sunlight for any length of time.  This is something to consider when choosing a garage floor finish.


Polyurethane Floor Coating Benefits

Like epoxy, polyurethane is a thermosetting polymer as well and is considered a high performance coating.  It is commonly known as urethane for short, though that it is technically incorrect and there is actually a big difference between polyurethane and urethane.  If someone is advertising a urethane coating, it is actually polyurethane.

Of the different formulations available, aliphatic polyurethane is the desired choice for garage floors.  Though they are approximately 60% to 70% solids depending on the manufacturer, a polyurethane coating is only about 2 to 3 mils in thickness and can’t be adjusted as with epoxy.

Don’t let the thinner dry film thickness fool you however. Aliphatic polyurethane has more flexibility than epoxy and it is this flexibility that aids in absorbing impacts better.  It is also much more abrasion resistant.  In fact, some manufacturer’s claim that the wear resistance of polyurethane over epoxy is almost 3 to 1.  The resistance to chemicals is better than epoxy as well and this includes resistance to solvents such as methylene chloride which is the primary ingredient in paint stripper.

Another advantage of polyurethane over epoxy is that it is U.V. stable.  This means that it won’t yellow like epoxy does when exposed to small amounts of sunlight over a period of time.  The surface of polyurethane is not as hard as epoxy but it is much more scratch resistant, can tolerate larger temperature swings, and handles humidity much better.  It is also available in different finishes from satin to very glossy.

Though polyurethane has many advantages over epoxy, it does not bond well to concrete and its thin dry film thickness will not work well as a self-leveling coating to fill in small cracks and divots in the surface.  Another consideration is that most polyurethanes are solvent based, meaning they can have high VOC’s, and may require a respirator to apply.

Final Verdict

So, which should you use?  As a rule, it is believed that you will get maximum performance by using both polyurethane and epoxy together for your garage floor coating.  Whether you are applying the coating yourself or hiring a professional, epoxy is best used for building up the thickness of your floor coating then following up with polyurethane as a clear coat to protect it.  It will help protect the epoxy from yellowing and it will provide for a longer wearing and more scratch resistant surface.

If you don’t want to worry about yellowing at all, you can always use a colored polyurethane as a color coat before the clear coat.  Polyurethane is also a better medium than epoxy to mix in anti-slip aggregate if you truly want an anti-slip surface or want a solid colored floor without paint chips.

Something else to consider is that most epoxy clear coats are not actually crystal clear like polyurethane is.  Though they have no color, there is a slight yellowish brown tint to the clear in epoxy.  Unless you opt for a more satin finish, polyurethane can provide a very glossy surface that gives your floor depth.

So unless you are just doing a one-coat epoxy coating for your garage, a combination of epoxy and polyurethane is almost always the best answer to get the maximum combined benefit out of both materials.  The result is a high performance garage coating that will stand up to the rigors of a working garage for years to come.

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Comments

  1. I wish I would have found this out for the first garage I did. My first floor turned a little yellow before a year. I know polyurethane is tough because I used it on my second garage in the house I’m in now and it is awesome. 5 years now and it still looks new and glossy with no yellow color.

  2. Fordman says:

    You said that polyurethane is U.V. resistant, but will the epoxy under it yellow? I don’t want to spend the extra money urethane if it does.

    • That’s a great question Fordman and thanks for stopping by. The polyurethane top coat will filter out the U.V. rays and protect the epoxy underneath from turning yellow. Think of it as a sunscreen for epoxy.

  3. Great Post. This is exactly what I was looking for. I am getting ready to paint my garage floor with 2-part epoxy paint (solid-based). After researching, I realized this epoxy will discolor from UV rays and I plan on leaving my garage door open for several hours a day in Florida. (I have my reasons.)

    Could you please give some suggestions for some aliphatic polyurethane products. I’m having a hard time finding a product that I’m sure is aliphatic and that will work well with the Rust-oleum Professional Epoxy Garage Floor coating. Any suggestions would be greatly appreciated!

    Thanks!

    • Thanks for the kudos Jay. As far as finding aliphatic polyurethane floor coatings, it’s not as hard as you think. Remember if you are doing a search that many companies refer to them as ” urethanes”. When looking, be sure to check the TDS sheets. Legacy Industrial has one here and Concrete Solutions offers both a water based polyurethane and solvent based polyurethane.

      Most companies are more than happy to talk to you about the compatibility issues of using their brand in conjunction with another. It’s the smart thing to do. Good luck with your project!

  4. I am checking to see if I can use clear epoxy over a concrete floor dye? Or will the dye not allow the epoxy to affix itself properly to the concrete for good adhesion?

    • Hi Jimmy and thanks for visiting us. Yes, you can epoxy over a concrete dye or stain. Dyes penetrate the concrete to leave a colored residue without forming a film and stains react with the free lime to create color. Just make sure that the concrete surface has been prepared properly to accept the epoxy. Also, it’s always wise to check with the manufacturer of the color dye to make sure it doesn’t react with the epoxy.

  5. Can I epoxy over VCT tile that has been stripped of wax/sealer and hand sanded with 80 grit sandpaper? Will the epoxy bond to this substrate? My plan is to epoxy over the VCT tile and then apply a coat of aliphatic urethane. Assuming this is ok to do, how long should I allow the epoxy to dry before applying the urethane?

    • Hello Jody and thanks for the great questions. Yes, you can epoxy over vinyl composite tile with the prep methods that you just described and be sure you wipe it down with denatured alcohol as your final step. You should use a 100% solids epoxy because it will provide for a thick coat and self level over any small gaps between the tiles. Unless using an accelerator, wait a minimum of 10 – 12 hours before applying the urethane. The epoxy should not be tacky to the touch. Don’t wait longer than 24 hours or you will have to prep the surface of the epoxy.

      • I have 2 different paint specialists from Glidden and Devoe telling me that any 2 part epoxy or 2 part urethane is not safe for VCT tile because of the chemical reaction. They say the chemical reaction could melt the VCT tile and adhesive. They also say that neither will bond properly to the tile. Is this true? I only want to do this one time and I want to do it right.

        Thank you.

  6. Peter Moriarty says:

    Great article. Clear and helpful. to the question of who makes aliphatic urethane, one company with which I have had commercial success is TNEMEC – spell it backwards and it spells cement. They are a leader in above ground water tank coatings but I don’t know if their product is available retail.

  7. Rafael Medhat says:

    Great Article..
    But I want to ask about a floor of workshops; mechanical, electrical and projects workshops. Is the epoxy better or the polyurethane? Knowing that the floor of the workshops is at the same time the surface roof of water tank..
    I am tending to the side of the Polyurethane but still want to hear your opinion.

    • Yes Rafael, a polyurethane coating in most cases is going to be the better choice of the two when used in a work environment. It will provide for better scratch resistance, wear, impact resistance, and better resistance to chemicals of all types.

      • Rafael Medhat says:

        Thank you Shea for your reply, yes as many told me..Polyurethane is much better than Epoxy in my case/conditions.
        Can I ask you also about the “Polished Concrete” !? Could it be used or still the polyurethane the best choice !?
        Thank you in advance and waiting for your reply..

        • You can do a semi-polished concrete surface with a special sealer. It would be similar to the concrete floors that you see in some warehouses and big home improvement centers. Unlike a polyurethane coating, they do require work to stay maintained and will not be as resistant to some chemicals.

  8. Anna Olver says:

    I just used 100% solid epoxy w/ flecks (from JAM flooring) on my garage floor. I didn’t realize it was going to be slippery when it gets wet, which… it will. I live in NE PA w/ long winters. What can I use to make it non slip & where would I get it from?

    • Hello Anna and congratulations on your new floor! In order to create a non-slip surface, a non-slip additive such as Shark Grip should have been added to the mix when you installed it. What you can do however is apply a top coat of clear epoxy or polyurethane to your Jam flooring base coat with a non-slip additive added to that. You will need to lightly sand or roughen up the surface of your new epoxy before applying a top coat. Polyurethane has a higher spread rate than epoxy and makes for a good medium for a non-slip additive. You might want to call one of our sponsors such as Legacy Industrial. They have these type of products and can give you and estimate for materials.

  9. If using epoxy over VCT flooring does it need to be primed before the epoxy is applied? And do you need to prep the epoxy for polyurethane

    • Hello Heidi and thanks for the good questions. In most cases a primer is not necessary if you want to epoxy over VCT flooring. Make sure the tiles are clean first (no wax either) and then you need to rough them up for the epoxy to adhere properly. If the tile isn’t down yet it’s generally a good idea to rough them up first. The reason for this is that opposite colors can bleed together if not done carefully (black and white tile for example).

      100% solids epoxy is recommended and contact the manufacturer first to determine if there are any compatibility issues. Squeegee the first coat on real thin to just fill any gaps in the tile. This will help to prevent out gassing and is also referred to as the grout coat. Then apply a full coat as normal followed by the polyurethane. The poly just goes on within 24 hours of the epoxy, no prep needed. Just follow the manufacturer’s directions.

  10. I painted my old tile kitchen counter with two coats of Homex epoxy paint. It seems to still be a bit soft in some spots and I painted it about 2 weeks ago. I want to strengthen the paint with a few coats oil based clear polyurethane. Do I need to sand it first? I reviewed your previous comment/responses and it seems as though it will help protect it. Your thoughts? I am going to paint my tiled bathroom floor as well…

    • Hello Amber. Almost anytime you apply an epoxy or polyurethane to a finish that has cured for more than a day, you will need to roughen up the surface by sanding or using an aggressive scrubbing pad. Always follow the manufacturer’s recommendations for preparation. My concern however would be the soft spots that you still have after two weeks. You don’t want to apply anything over it until it is cured properly.

  11. Kind of an odd question but I’m redoing my bathroom floor with pennies and I’m looking for a topcoat to protect the floor. I found your post very helpful but I was wondering if anything that is sold at a big box store like Lowe’s would be an aliphatic polyurethane floor coating or can I even use it over the cooper flooring. I want to be very careful with my choice since there is a window and it does get direct sunlight, I don’t want it to yellow on me. Also, would obscured glass filter out the U.V. Rays?

    • Wow, a penny floor sounds cool! Polyurethane wouldn’t be a good initial coating because it’s too thin to coat the pennies with. Epoxy is a much better choice because it can be applied in much thicker coats, but it will yellow in direct sunlight. Glass will slow the process down but it will still eventually yellow. A final coat of polyurethane would slow the process down even more but you would eventually end up with the amber appearance. I think your best bet would be to coat the pennies with polyurea. Polyurea cures crystal clear and U.V. light will not make it yellow.

  12. Anti Slip Floor Coating provides better protection from abrasion and chemicals and it comes in a variety of color options.

  13. I want to use a solid epoxy on my garage floor but I am wondering who is recommended in my area of Overland Park, Kansas. Any ideas and price ranges for this type of floor per square foot?

    • Hello William. Pricing can vary depending on region. It can be anywhere from $3.50 – $5.50 a square foot depending on the amount of coats plus other factors. I would contact Gene Dean from Elite Crete Indiana. They are a decorative concrete and epoxy floor coatings supplier that also trains installers. He is the Director of Training and Tech Support for the company and is in contact with many installers through out the mid west that he may be able to recommend for you. Just call the number on the site or you can email him at info@elitecreteindiana.com

  14. Hi Shea,
    First, props to a great website…this is a very helpful resource! Second, I have a slightly different application. My wife and I are repurposing an old turn of the century salvaged door (that was never hung) into a dining room table. To fill in the low spots (panels), we will be using 1/8 inch layers of epoxy. The epoxy instructions recommend applying a coat of oil based polyurethane to provide adhesion between any old paint and the new epoxy coat. My question is…how long should we wait when going from the poly to the epoxy? I saw your previous reply about waiting 12 hours to go from epoxy to poly…does the reverse still apply?

    • Hello Corey. Sounds like a cool project! Yes, the reverse holds true as well depending on temperature and humidity. The best way to test to see if it’s ready for the epoxy coat is with the thumb print method. When you press your thumb to the coating it should not feel tacky or leave a thumb print. If it does, then you need to wait a little longer. If it doesn’t, then it’s ready to go.

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