Pinholes in concrete - epoxy

[dangti6]

I posted a few months ago about an issue with my concrete floor surface here

I ground the floor with a large machine and diamond grinding disc to a solid surface apart from what I thought was a limited number of pinholes in the concrete which looked deep enough to the point grinding the out would be unachievable.

I have applied a 2 pack epoxy coating which has filled some pinholes but due to the build of the epoxy it obviously hasn’t run down filling many of the holes. As I say, I knew there were some pinholes but now the floor is a light grey the holes stand out and appear much more prevalent than I’d realised.



In one area there are a lot. 2” brush for scale



I’m considering a second top coat of epoxy but doubt that will simply fill the holes that it didn’t the first time. In hindsight I should have gone over the surface with a grout/slurry to fill them but here we are.

What are my options to consider now if any?

Part of me says to leave it and cut my losses as I am. I don’t intend to have wet cars in there or spill stuff all over it as any fluids would be caught on trays/mat

Thanks in advance for any words of wisdom, guys

 

[p00p]

resurface the concrete, apply a thin top layer & then recoat it. Ripping it all out & doing a fresh pour would likely be best.

 

[toreadorxlt]

I had similar issues, not that bad. I assume you didn't prime? Its from your concrete breathing when the epoxy was curing.

I ended up renting a floor maintainer, deglossing the floor, wiping with denatured alcohol and topcoating. I too was on the fence, but glad I re coated. The first ugly layers of epoxy ended up like a primer coat for the final glory coats, and my mil thickness in the end was thick.

 

[dangti6]

I had similar issues, not that bad. I assume you didn't prime? Its from your concrete breathing when the epoxy was curing.

I ended up renting a floor maintainer, deglossing the floor, wiping with denatured alcohol and topcoating. I too was on the fence, but glad I re coated. The first ugly layers of epoxy ended up like a primer coat for the final glory coats, and my mil thickness in the end was thick.

I primed it with what was branded as a sealer. It was a solvent heavy and appeared to absorb in to the concrete well.

They appear to be deeper than the epoxy is thick, if that makes sense so I believe they would have already been there rather than holes being created by released air.

I used a roller sleeve rather than a squeegee as per the manufacturers recommendation. I wonder if using a squeegee for another coat my pull the epoxy in to most of the pinholes to improve it over how it is now.

 

[p00p]

I used a roller sleeve rather than a squeegee as per the manufacturers recommendation. I wonder if using a squeegee for another coat my pull the epoxy in to most of the pinholes to improve it over how it is now.

From my experience with epoxy coating is that it is best to apply many thin coats working each application into the surface. If applied too thick, it would bubble or create air pockets that would later expose voids (like pictured). If the product allows; You could thinning the epoxy to float it into the holes. Just allow for it to dry before the next application. As much as we tend to want a quick process, epoxy requires patience for the best finished surface.

 

[dangti6]

Thanks pOOp.

I reckon when I was laying it down I saw an even coating filling over the holes and as it’s settled and dried the air has later exposed the holes as you suggest.

I will write to the manufacturer and see which type of thinners they recommend works best with their epoxy, thanks. Thinning by up to 10% appears a common suggestion from looking online.

 

[Armorpoxy]

Try using a 100% solids epoxy that you pull over the floor with a flat squeegee to fill the holes. A 100% solids will cure and not shrink since it has no solvents or water. Then, once repaired, recoat.

 

[tncatadjuster]

Those are the weep holes of the water that came to to the top concrete as it cured. Grinding opened them up and the epoxy ran down into the hole and produced what you see. Thinning does not always help, just produces bubbles instead of volcano. ArmorPoxy has the best solution.
I viewed the other thread, you really needed double prime coat.

 

[LegacyIndustrial]

Those are the weep holes of the water that came to to the top concrete as it cured. Grinding opened them up and the epoxy ran down into the hole and produced what you see. Thinning does not always help, just produces bubbles instead of volcano. ArmorPoxy has the best solution.
I viewed the other thread, you really needed double prime coat.

All concrete is NOT created equal! Have to match your strategy to the surface you have uncovered post-grinding.
Generally a primecoat is enough but (2) probably would have prevented the issue as my friend from TN noted.