A few Epoxy Coat questions....

[flypa38]

Hi fellas,
Bought a house and decided on Epoxy Coat for the garage floor. I had a few questions though.
As far as prep, what should I do with the concrete. I've read a lot on here about it, but seems different for each situation. The concrete is about 5 years old and is untreated and I didn't notice any cracks or stains. Should I etch with an acid solution? Just pressure wash? How long should it dry before applying the epoxy after washing?
Not sure on the flakes....without clear coat, does the flake cause a rough or raised texture? Not sure I want them in there anyhow.....
Speaking of clear, how glossy will it be without clear? Any comparison pics with and without clear?
I wanted the gray shown on Epoxy Coat's website. Lowe's shows dark gray and light gray. Which if any is the one referred to as just gray on Epoxy Coat's website?
Finally, what is a good dry time before I start moving things in? I've read about how fast it sets, and I've seen 18 hrs. Which is it?

Thanks,
Sorry if these have all been answered before. There are a ton of questions here and didn't have much luck searching for all of it.

Johnny

 

[mo2872]

Diamond grinding is considered the "best" prep method by many. I have done several with just acid etch, but that has been on fairly new, unused concrete. The only one I have done the grinding on is on our attached garage "re-do".....
http://garagejournal.com/forum/showthread.php?t=145123

That is the "taupe" color from EC, with "Hockeytown" flakes from Original Color Chips, no clear. "If I had it to do over", I would put the clear down, if only to keep the white flakes from discoloring with tire marks!

I kind of like having them uncovered, though, as they(the flakes) provide some small measure of anti-skid.....not much, but some! One of my neighbors put in the "dark" grey, and it's more of a blueish gray. The taupe, at the time, was more of a light whiter gray.

Hope that helps a bit!

 

[Jaguar Fan]

• BEFORE YOU DO ANYTHING ELSE, perform a vapor barrier test. Get a 1 yard piece of plastic tarp or equivalent and tape it to the garage floor sealing all the edges with duct tape. Let it set for 24 hours. Pull it up. Is the underlying concrete damp? Is there evidence of condensation on the plastic tarp? If so, this probably means there is no vapor barrier underneath the slab, and as a result a do-it-yourself epoxy would most likely fail. If it is damp, come back to the forum & ask for more help. If, once you pull up the plastic, everything is dry, then go to step 2. (By the way: for such a new slab, my guess is it most likely has the vapor barrier and you'll be fine).
• Assuming you pass the vapor test, then you need to remove the laitance. Grinding or shot blasting are the gold standards. IMHO based on your description, acid etch will be fine to remove the laitance for your use because your concrete is in very good condition (no oil stains that might cause the liquid acid to "bead up".
• For a definition of laitance, read http://www.concreteconstruction.net/concrete-articles/meaning-of-laitance.aspx and http://en.wiktionary.org/wiki/laitance
• Why remove the laitance? Read http://www.contractflooringjournal.co.uk/archive/helpnov04_2011.html specifically

  "...Laitance is always present on new concrete and must be removed...Laitance comes in varying degrees of thickness, from a fine dust to several millimeters or more, depending on contributing factors...If laitance is left untreated, the application of subsequent materials... will have a high risk of failing."

• If you do not remove the laitance prior to installing the epoxy, over time, the risk is that the laitance will delaminate from the underlying concrete aggregate and pull up.
  
• If you decide to acid etch, then you need to get everything out of the garage, and scrub it with a good concrete cleaner, and rinse it with a powerwasher. Re clean & re-rinse.
  
• Go ahead & etch with diluted swimming pool acid. Read the threads here to see the technique. Afterwards, powerwash several times.
  
• Let it dry for at least a week. Then do the tarp test again; if it comes up damp, let it dry more.
  
• Now it is time to apply epxoy.

Here's a link to one project I've done (http://www.garagejournal.com/forum/showthread.php?t=16957) - because it was a pretty new slab, I prepped with acid. It looks as good today as it did they day after it was complete. I've had no problem with epoxy coming up.

See http://www.garagejournal.com/forum/showthread.php?t=16957

To see how the exterior exposed 6" of garage slab (that is, always in the full Las Vegas sunlight) compares to the rest of the garage, see http://www.garagejournal.com/forum/showthread.php?t=22391

 

[LegacyIndustrial]

Laitance is best removed with a grind. You will never know if you truly removed it using acid etching. Ask me how I know.