Water beading after grinding

[snowbird122]

I'm doing a diamond grind on my 38 year old concrete garage floor in preparation for epoxy. Even after grinding several times , I'm still seeing water beading up some places. Is this normal? Do I need to keep grinding until the water doesn't bead?

 

[benwah]

Does your floor have a lot of oil/chemical stains? Can you post some pictures?

 

[snowbird122]

I pressure washed and then used a scrub brush and a degreaser, but I still had water beading in a few spots. After diamond grinding, there are still 5 specific spots (each about 2 feet in diameter) where the water is beading. I've probably spent 4 hours grinding just on those spots. Should I keep going until it stops beading?

 

[benwah]

I would suggest using a heavy duty degreaser on your floor. A manufacturer like Kem Tech should have something that you could use.

It looks like others have had luck with some products from Lowe's and HD also!

 

[snowbird122]

I'll try the previous degreaser I used. Any idea where I can buy the Kem Tech stuff? Is the bottom line here that I have to get rid of the beading before applying epoxy?

 

[benwah]

You would have to give them a call to find the nearest distributor.

Yes that is the bottom line. If water will not penetrate into the substrate, expect your epoxy coating to do the same. The epoxy will cure, sure, but it wont penetrate. That means it is literally sitting on top of the concrete and will peel right up.

Try your degreaser heavily in the areas that are beading. Be sure the concrete is dry when performing the water test.

 

[snowbird122]

Well, after using my degreaser (this highly rated one on Amazon), you can still see the water beading up. I'll look for a place to buy the recommended degreaser. Meanwhile, please let me know if there are any other ideas for me to try.

Thanks so much for your help.

 

[rigore]

I have not painted my floor yet but the first thing I did was use a product called Oil Eater. My company sells the product and I had a demo by the OE rep and I remembered him talking about oil stains in the garage. I sprayed the product on the oil stains, came back several hours later and the oil was on top of the surface of the concrete, wiped it down and sprayed the area again. The product kept pulling up the oil day after day until it was gone. Not sure it will work for you but its worth a shot. I have seen the product in Costco in a 2ea 1 gallon package for like $10.00. Good luck.

 

[Shea]

Are the spots about the same distance apart as a set of car tires? If so, you may have tire dressing that has soaked into the concrete. These are usually silicone based and are almost impossible to remove chemically.

The best way is to grind down a 1/16" or more to remove the contaminated concrete. Once it's finally gone, the best bet is to fill and level the spots with a 100% epoxy slurry of silica aggregate to make the areas smooth again.