Ground my Concrete Garage this weekend

Tidybuoy · 10-16-2017, 11:28 AM

Prepping for epoxy next weekend. My garage has two slabs separated by a control joint. There was a 1" lip where one slab raised over the past 70 years and so I rented a machine and ground it down to smooth. Took all day Saturday but it's now smooth.

I'm acid washing tonight and then after a couple of days drying, I will prime. Epoxy coating on Sunday.

After sanding the floor but before grinding down the lip:

After grinding the lip down:

The Machine:

berettafan · 10-16-2017, 11:34 AM

Nice!

My slab was power troweled and you can't even find an oil spill on it. Clean floors are so nice. What color you doing?

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onewhippedpuppy · 10-16-2017, 11:37 AM

Looks good. I normally DIY but hired a company to knock out my epoxy work. They ground the entire floor to remove the stains. I LOVE the end result.

Bill Douglas · 10-16-2017, 12:17 PM

Very Tidy.

I like the look of the polished concrete that's been fnnished with polyeuthane.

Tidybuoy · 10-16-2017, 02:01 PM

Quote:

Originally Posted by berettafan

Nice!
What color you doing?
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It's called Harley Gray, similar to the photos below but will depend on how much fleck I broadcast. The kit came with 20 lbs of flakes (which is about a 5 gal bucket), so I will decide when I start sprinkling.

GH85Carrera · GH85Carrera's Garage

I bet that grinder is one noisy machine.

Great looking floor.

enzo1 · 10-16-2017, 03:37 PM

??? Why do you have to acid wash after grinding?...

Tidybuoy · 10-16-2017, 04:30 PM

Quote:

Originally Posted by enzo1

??? Why do you have to acid wash after grinding?...

I'm not sure why I have to acid wash but that's what the manufacture recommended. I don't think it will be too much extra work and I will feel better - especially since the grinding did not get every single spot. You will notice in my photos that there are some dark patches....this is where the concrete dips a tiny bit and so the blade on the grinder just scrapped the surface but did not grind off much. I feel that the acid wash will take care of any missed spots as well as the edges and corners that were handed sanded. I also have to fill some minor spalling and the fill material recommends acid washing first.

sc_rufctr · 10-16-2017, 04:31 PM

Quote:

Originally Posted by enzo1

??? Why do you have to acid wash after grinding?...

To remove the fine concrete residue left after grinding.

enzo1 · 10-16-2017, 04:44 PM

Quote:

Originally Posted by sc_rufctr

To remove the fine concrete residue left after grinding.

you can do that with a pressure sprayer...think i'm getting this mixed up with acid wash "stain" which is probably different

sc_rufctr · 10-16-2017, 04:53 PM

You could use a pressure washer but fine concrete residue is really difficult to get rid of.

I've often done my own floor tilling. The best thing I've found to remove tile glue residue is a large dry towel. It just wipes off easy peasy.

cabmandone · cabmandone's Garage

Amazing what the right tool for the job will do isn't it?
Now that you're at this point, don't use a pressure washer to rinse. With the sealer all but gone you'll drive moisture into the pores of the concrete if you use a pressure washer. So if you're going to etch, rinse with a hose and as I mentioned before, you'll want to use a baking soda/water mixture to neutralize the muriatic acid. I was told when I did my floor not to etch if using a grinder. The concern was the acid leaving a film on the floor and having areas where PH was higher. Don't know why PH was a concern but must have had something to do with adhesion.

Also, when rinsing the floor, pay attention to how it acts when hitting the floor. If the sealer is all gone, you shouldn't have water beading.

berettafan · 10-17-2017, 07:30 AM

OP if any doubt be sure to call mfr. one theme I find in garage floor threads is you must follow directions precisely.

can't wait to see finished pics.

aschen · 10-17-2017, 07:55 AM

its going to turn out great i'm sure, grinding is the better method. I also thought that there is no need to acid wash if you ground. I had a newish clean slab so I just did the acid wash, and honestly one of the bigger PITA was rinsing the old acid and reactants away. I had to keep respraying to ensure it was gone.

I'm sure I used less than a gallon of flakes for my 3 car, 5 gallons will be very heavy

Tidybuoy · 10-17-2017, 10:59 AM

Quote:

Originally Posted by cabmando

Now that you're at this point, don't use a pressure washer to rinse. With the sealer all but gone you'll drive moisture into the pores of the concrete if you use a pressure washer. So if you're going to etch, rinse with a hose and as I mentioned before, you'll want to use a baking soda/water mixture to neutralize the muriatic acid.

Thanks for the advice. Makes sense that the pressure washer will force water into the concrete and knowing me, I would spray & spray & spray.

I will give the manufacturer a call today and confirm that I should be using acid, since the directions do not know that I used a grinder.

Tidybuoy · 10-17-2017, 11:06 AM

OK, I called the manufacturer and he told me that I don't have to etch after grinding. However, I mentioned that I still have some dark spots where the grinder did not grind due to grooves in the cement. He told me that in that case, I should definitely etch and do extra scrubbing over any dark spots in the floor. He also suggested rinsing with a hose and not use a pressure washer.

Well, based on this advice, my brand new pressure washer will stay nice an new for now.

cabmandone · cabmandone's Garage

Get a grinding wheel for a 4" hand grinder and hit those spots. Use it to feather into the clean stuff and call it a day. I bought a Bosch diamond wheel for my hand grinder that worked great! I tried one of the cheap ones and it marked the surface too much. The Bosch seemed to work well.

Oh and Spike Shoes! Don't forget spike shoes!

I used about a 5 gallon bucket of flake on my 24x40 and came out with a really nice heavy broadcast look. I don't recall what size your garage is but it seems like with a 5 gallon bucket you're going to be close to a full broadcast which will be very little of the epoxy paint showing. This is where the spike shoes come in really handy. You can just walk around tossing the flake until you're happy.

Tidybuoy · 10-17-2017, 03:45 PM

I already have the 7" Bosch diamond wheel and I ground away much of the dark spots last night. I think I will go that route tonight and finish up all the remaining spots. After that, I can vacuum and rinse and then skip the acid wash all together.

I already bought 2 pairs of spiked shoes (for me and my helper) so I'm good to go there.

My garage is 17x26 and the shop area is 8x14 (total of 554 sqft) so my 5 gallon bucket of flake will be enough to do light to full heavy coating. I will start light and see how it looks. I want t make sure if covers any imperfections in the floor.

Getting excited to finish (nervous too).

I've got new cabinets to install after the floor and then the garage is going to......showoff worthy

john70t · 10-17-2017, 03:59 PM

Quote:

Originally Posted by sc_rufctr

You could use a pressure washer but fine concrete residue is really difficult to get rid of..

What about a compressor @125psi w/blowgun attachment and screw in a 4' brake line?

Tidybuoy · 10-17-2017, 04:41 PM

Quote:

Originally Posted by john70t

What about a compressor @125psi w/blowgun attachment and screw in a 4' brake line?

hmmm...that is a thought. After I vacuum, rinse, dry, I will give the area a high psi blow with the compressor. I think I already have the attachment I need.