Polyurethane top clearcoat over epoxy???

Zmw · May 20, 2013

I am about to start my garage floor remodel. After days/weeks of doing research I am still not 100% sure on how to proceed.

Originally I wanted a base gray epoxy coat, and a clear coat epoxy on top. After I bought all materials, I am finding out that clear epoxy will yellow overtime and that is not appealling to me. I live in PHX, lots of sun! (I originally wanted to use epoxy-coat, but a former flooring professional at Lowes sold me on quickrete/valspar product. I hear mixed reviews on it, but it seems less chance for a DIY fumble/easy application and it bonds nicely with the concrete)

Should I put down my base gray epoxy with flakes, and skip the clear coat epoxy and go with a poylurethane that has uv resistance? Will that keep the gray epoxy underneath from yellowing as well?

I am seeing poly's at $150 and under for 500 sq ft. Can anyone help - any products you suggest? Is Polyurethane strong and will hold up just like epoxy will? Anything important to look for in a poly product?

Any help is appreciated.

Okolowicz · May 20, 2013

I am probably the last person to give anyone advice since I have yet to actually put the epoxy down. However, considering the vast majority of the work is the prep, it seems to me that the wisest choice is to use the best quality product available. All my products have been ordered but over the past week I have done the following:

-Moved all the contents of the garage to the spare room/office of the house (which the wife hates).
-Spent two days grinding with the Diambrush
-Vacuumed and Cleaned
-Spent better part of a day with the angle grinder getting the edges, steps, and missed spots
-Vacuumed and Cleaned
-Etched with Muriatic
-Etched with Muriatic again
-Rinsed
-Cleaned and scrubbed with TSP
-Cleaned and scrubbed with ammonia
-Rinsed & Squeegied
-Rinsed & Squeegied
-Rinsed & Squeegied

No chance in hell I went through all of this effort to use a substandard product.

Zmw · May 20, 2013

Are you topping with a polyurethane? What product did you choose?

Okolowicz · May 20, 2013

I have not yet taken the plunge on the topcoat but I need to purchase before tomorrow to ensure I receive it by this weekend. I actually started a thread a few down from yours inquiring about compatible and/or recommended clear topcoats for Epoxy-Coat.

Back to my previous post for a sec: For as much research as I've done I couldn't say what I chose (Epoxy-Coat) is the best. It might be. It might not be. There are a lot of different brands promoted/recommended here on GJ that people have had success with (Epoxy-Coat being one of them). It does seem clear that a 100% solids epoxy is the best. And, I'm sure most any of them will provide an equally great floor. For me it came down to color and price. Ordering the Epoxy-Coat kit from Lowe's was cheaper than any of the comparable competitors (and cheaper than buying it direct from Epoxy-Coat!) and was the color I liked the most.

I digress... Back to the topcoat. I am still undecided except that I know I won't be using a clear epoxy because they seem most prone to yellowing. So, my choices are down to a 1 part urethane, a 2 part polyurethane, or a polyurea. I am very much looking forward to those with experience chiming in with some wisdom.

Here is an older thread with some info: http://www.garagejournal.com/forum/showthread.php?t=160651

Zmw · May 20, 2013

I found this old link, but guys are arguing over what is better and no one mentions products. http://www.garagejournal.com/forum/showthread.php?t=160651&highlight=high+performance+urethane

Any insight or expierence with particular products?

What about - http://www.corotechcoatings.com/viewCat.asp?catID=205

or

http://www.ebay.com/itm/High-Performance-Urethane-HPU-Clear-Coat-Topcoat-/370300513046

Zmw · May 20, 2013

Can anyone recommend any products they have used with success?

http://www.worldpaintsupply.com/cor...ethane-high-gloss-clear-coat-827-10-1-gallon/

or

http://compare.ebay.com/like/370300512104?var=lv&ltyp=AllFixedPriceItemTypes&var=sbar

AlphaGarage · May 20, 2013

Just speaking for our products (although this most likely applies to most)... Yes, the epoxy, even a 100% solids one, is UV reactive. We've improved a lot in this area, but still over time an epoxy coating will color shift due to UV exposure.

Our polyurethane clear coat (EnduraShield 2254) by itself is UV stable. We have a lot of outdoor applications, everything from chunks of the Berlin Wall to military antennas, and years later the EnduraShield is still crystal clear.

When applied over a layer of epoxy the EnduraShield will filter out a lot of the UV, but not all of it. So the underlying epoxy may still color shift over time. There are a lot of factors that determine the extent of the shift, it can be substantial, but in other cases unless there are side by side sections it can be indiscernible.

The epoxy's original color also comes into play, tan and beige epoxies handle it quite well. intense reds, blues etc. not as well.

An additional layer of clear coat will mitigate UV and lessen the shift.

LegacyIndustrial · May 20, 2013

Epoxy will "amber" over time. Why? because it is NOT UV stable. Little secret: clear epoxy is amber in color to begin with, not truly clear.
Placing a clear urethane over the top will not stop it from eventually ambering.

It may retard it but if exposed to UV it will go.

Clear urethane will not yellow/amber. It is truly clear, not amber like epoxy.

If you want a colored floor that will never amber, topcoat your epoxy with a pigmented urethane.

Here is one we offer: http://legacyindustrial.net/cart/hd322-urethane-coating-15-gal-p-173.html

pauloman · May 21, 2013

99% of clear non epoxy coatings have little or no UV blockers so while the poly (hopefully 2 part LPU) will not yellow, the epoxy under it will. Only two exceptions I know of - Auto Clear Coat and Acrylic Poly UV plus. Why? When I had a 2 part poly formulated for me adding the uv protection added over $10 a gallon to the raw material costs, and that was about a decade ago.

mharris2007 · May 21, 2013

I used wolverine coatings to do my garage floor with the patient assistance from Fred who was absolutely great. I used his urethane clear coat called endurashield. My garage floor extends about 2 inches outside of the garage door and is constantly in the sun. That 2 inch strip has in fact yellowed even with endurashield on it. However, the other 99% of the garage which is not constantly in direct sunlight looks as good as the day I laid it down. It is really luxurious to have an epoxy floor with urethane. I can take a picture and post it up here if you'd like to see.

Matt

Zmw · May 21, 2013

Thanks for the info Matt. I am now planning to not coat that 2 inch part of the slab that extends past the garage door. I guess it will look funny either way.

Did your urethane yellow, or the colored epoxy underneath? I was wondering if the gray epoxy all by iteslf outside will yellow and change color as well. I am guessing it will...

mharris2007 · May 21, 2013

Zmw said:
Thanks for the info Matt. I am now planning to not coat that 2 inch part of the slab that extends past the garage door. I guess it will look funny either way.

Did your urethane yellow, or the colored epoxy underneath? I was wondering if the gray epoxy all by iteslf outside will yellow and change color as well. I am guessing it will...

I have no idea which one yellowed, but I would guess it was the epoxy underneath. Either way when you look at it, it looks yellow. But like I said, all of the epoxy inside has no yellow in it at all.

Zmw · May 21, 2013

I think my plan is set. I am applying 2 coats (2 boxes each coat to 450 sq ft) of valspar/quikrete gray 2 part epoxy. From what I have read 100% solids is thicker and perhaps stronger, but the valspar should be easy application for a DIY, and the water based absorb into the concrete well and really bond. 2 coats should look nice (I hope)

I am flaking and then adding a clear coat - High Performance Urethane Clearcoat kit (500+ sq/ft) 1.5 gal - from original color chips. I am passing on the No slip additive as 4 boxes of flakes should add good texture even with the urethane coating. (I have heard non slip additives reduce the strength of the bond or can cause a pitted look over time as the sand or granules break down.

I am not epoxying the 2 inches that stick outside of garage door due to matt's (and others) comments on yellowing.

Does this sound like a decent plan, or am I crazy or missing something?

LegacyIndustrial · May 21, 2013

Flakes do not create greater COF.
Most companies do not use "sand" as a non-skid anymore.

Most of us supply a ground polypropylene which proves to be really good for a garage environment.

porschedude996TT · May 21, 2013

mharris2007 said:
and is constantly in the sun.

Matt, that can't be, the sun needs to set once in a while.

LOL

gobble · May 21, 2013

I'll say that I did full flake without the no-skid and seem to be constantly hosing it down to keep it clean. My floor isn't the least bit slippery when it's wet.

Zmw · May 21, 2013

can the ground Poly be used with urethane topcoat as well?

Zmw · May 21, 2013

Gobble - do you have a top clear coat? Or just 1 coat and then the flakes? I was told that the flakes will create a decent texture even with a topcoat so the floor will not be slippery.

I read a post here where someone had issues with roller marks in their clearcoat when they used shark grip as non skid.

gobble · May 21, 2013

I have clear over the top.

Shea · May 22, 2013

Polyurethane over full paint chips will sometimes give the floor a pebble like feel since it's not as thick as epoxy. This can sometimes aid in grip with certain types of shoes, but the actual coefficient of friction is not any better with or without the chips. Here is an article about epoxy vs polyurethane that helps to explain the differences and how they work together.

pauls_workshop · May 22, 2013

On my floor, I used medium chips and also sharkgrip at about twice the dose they recommend on the jar. Then used clear epoxy-coat on top of the basecoat with the sharkgrip mixed in with the clear coat. The chips DO raise above the general level of the floor a little bit. The sharkgrip is so small that you don't really "see" it much in the top of the clear coat but it is there. Double the dose also does not seem to be a negative in any way. As a mechanical engineer, I'll comment on friction a little bit here. The "local" coefficient of static friction above a chip vs next to a chip would be the same with the clear coat over it, however, and this is a big difference, the "bulk" coefficient of static friction over several square inches with chips vs without, with a thin enough clear coating to not completely flatten out over the chips, would indeed be a higher coefficient of static friction. Your shoes will "dig into" the lower spots of the surface around the chips if the chips are higher than the general clear coat. A softer rubber sole would do this more than a very hard shoe bottom, but this effect would be present with any shoe sole. This "digging in" effect will create more friction. A technical term for this kind of effect is called Hertzian edge stress, but we don't need to go there! I will give you a metaphor for it. Think of taking a very thin book that is tall and wide (large area) and putting it on top of a big pillow. It will mostly sit there on the surface. Now take a similar area book but very thick, like a huge dictionary, and put it on top of the same pillow. you can try this at home. The thick dictionary will cause the pillow to "wrap around" the edges of the dictionary and the pillow will be "puffed up" around the edges of the dictionary as a result. Flip the pillow and book around in your brain and upside down and the sole of your shoe becomes the pillow, the chips are the book, and you get the point. Sharkgrip will provide even more friction, but without actually measuring it, I don't know if the friction my floor has more from the chips or more from the Sharkgrip. I think the chips are more than half of the friction though just testing it out. I have both and I'm not concerned about slipping on it at all and do recommend the Sharkgrip too. - Paul

Zmw · May 22, 2013

Thanks Shea and Paul. I am going to take another look at shark grip and read a few more reviews. As long as the roller streaks issue was a 1 time event and not many other people with the same issue I may jump on it.

I am used a polyurethane clear coat on top, so hopefully it goes on clear and streak free.

Thanks

pauls_workshop · May 22, 2013

Yeah Zmw, I don't know what any sharkgrip streaking comments were about. I used double the recommended amount and have no such issues. You can't really see it at all but it is there. I highly recommend it, but chips do alot on their own too as I explained, as long as they are bumps above the clear and not totally buried by the clear to be flat. - Paul

LegacyIndustrial · May 22, 2013

You need to fully back-roll your sealer. If it doesn't look right when you are done rolling, roll it again until it looks perfect.

Zmw · May 23, 2013

One more questions guys.

My hot water heater is in the garage and it sits directly on the conrete floor. It is Not on a stand of any kind. Should I simply use painters tape and tape around the water heater for each coat, and remove the tape while the epoxy and polyurethane is still wet?

Has anyone experienced this? Any tips? Thank you all!

Polyurethane top clearcoat over epoxy???

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