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Discussion Starter · #1 ·
Hi all,
Long time learner here, first post here in dire need of help.

We are a contractor doing epoxy flooring using Fosroc EPU100. Followed the book the to the T, good concrete, grinding, cleaning, primer, cleaning, two coats. Two guys spread out with a squeegee while 3 others rolled it out. Spreading was in some areas a little thicker than recommended but mostly was as specified.

So while removing the masking tape, some stubborn areas came out with some of the coating. Before patching it, we chose to chip away any neighboring parts that didnt stick properly, so we used a scraper/putty knife assuming good epoxy shouldnt peel using those, but it just keeps coming out it doesnt stop.

And now I am not sure if my whole job is defective and didnt stick properlyor we are just being too aggressive with it. It is our first time using this Epoxy-Polyurethane hybrid coating.

Please note that none of the areas peeled on their own, it was always a free edge that came out during masking tape removal or by deliberately scraping with a tool.


Advice would be greatly appreciated...
 

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What was the steps you prepared the concrete by?

How long did you leave your moisture meter taped and covered to the floor before you started?

Did you acid wash?

Is your paint an acrylic?Acrylics are notorious for peeling off like a glove,was it a two part system?

Did you properly mix the two parts?

I had an employee call me once on a garage floor to tell me that the 2nd gallon I left for him was clear and had no color in it.And he was out of paint?

I asked him "Do you see "Part B" written near the top of the can?"

His answer several seconds later "Uh"

Did you Prime it?
 

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Discussion Starter · #3 ·
We prepared by grinding, cleaning then priming, but no acid washing. And we never really used a moisture meter we just made sure the surface is dry for at least 24 hours.

The product is a two part system and was mixed pretty well using a mixing paddle for 3-5 mins at least.

I am not sure if it is an acrylic though - its an epoxy-polyurethane resin hybrid - I tend to believe that would technically be an acrylic. It is very flexible for an epoxy which does contributes to the problem, it just peels away like anything.
 

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Whatd it clean up with?

If you didnt put down a moisture test how do you know the moisture content of the concrete?

Heres another dumb question,did you read the directions on the paint?

Was there a "sweat in" time period ?

If the material peels off the concrete like "anything" not sure I wouldnt just go ahead and peel it all off and try again.

Is this the first concrete floor you've coated?
 

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Discussion Starter · #5 ·
We used an industrial floor scrubber with just water. We really skimped on that moisture meter part by assuming dryness.

I read the TDS over and over I kinda memorize it now lol. There was no sweat in period it states to immediately use after mixing.

This isn't our first but its the first time we don't use a hell lot of thinners which is kind of a standard procedure around here. It does help with sticking because its so thin, but it is also way weaker than it should be which I didn't want on this project specifically.

Now to be a little more specific it doesn't peel away TOO easy, we do have to use a putty knife and apply some force, but being a flexible coating you can actually catch that free edge and peel away a good bit more.


Thanks for keeping up with me, appreciated.
 

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I had an employee call me once on a garage floor to tell me that the 2nd gallon I left for him was clear and had no color in it.And he was out of paint?

I asked him "Do you see "Part B" written near the top of the can?"

His answer several seconds later "Uh"

Did you Prime it?
JHC! What a phucking nightmare! Is that kid out of the hospital yet or has he already had the last rites?
 

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Ok, Following CApainter's lead here.

The PDS shows that the Adhesion strength of Nitoflor EPU100 is: 1.5 - 2.5 N/mm²* [PDS]

Converting 2 N/mm^2 comes out to: 290 PSI [Conversion]

Comparing the Adhesion to some other Epoxy coatings:


It appears that the Nitoflor has a pretty week adhesion to concrete, plus the fact that the full cure takes 7 days... you may have lucked out, as the weak adhesion may just be normal.

I would do a sample on a separate piece of concrete though to prove that the material just has low adhesion overall. [Example]

For future reference, ALWAYS do at minimum a plastic sheet test on the concrete prior to applying any coating.

Do you know any of the following:
  • How old is the Concrete? (Is the PH an issue?)
  • Is there a Vapor barrier underneath the slab?
  • What was the Relative Humidity on the day you performed the application?
If you have any of the above answers it would help diagnose if its a failure or just the product itself.
 
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