New Garage Floor, Acid Etch or Grind

[arrowspark]

Hi, I'm planning on covering my garage floor with Shield-crete epoxy. I just bought a new house, and will be moving in end of September. The garage floor slab was poured about 3 months ago. I was wondering how I should prep the floor for the epoxy coating. Is it better to acid etch or grind the floor? Right now the floor is smooth. I don't have the tools to grind the concrete but I did buy H&C acid etch solution. The label said the garage floor should feel like 120 grit sand paper after etching. Also when you wash the garage floor do you guys put some sort of protective sheet over teh drywall in the garage to keep it from getting wet?

 

[KPSquared]

So much info on this site. As much as I would love to search through a bunch of threads for you, this question (and an opinion of which epoxy products are worth buying) has been covered a million times.

Take a little time to do some reading in the flooring section.

I vote for grinding but lots of guys have acid etched with good results. . .at least in the short term. With a grind you get a guranteed result as far as roughing the finish up.

Good luck with your research. Better post up some pics when you get it done!

 

[Garage Flooring]

Personally I believe grinding to be the best solution. Etching works in many but not all cases.

 

[LegacyIndustrial]

Acid etching is an option. However, diamond grinding is a better one.

If you do go with the acid, do it right!

Here are some instructions: http://legacyindustrial.net/images/How to Acid Etch.pdf

 

[Shea]

Arrowspark, it is always a tough decision to make as a home owner when you don't have grinding equipment. The above posts are correct about which of the two is the better method. If you do acid etch, just make sure you take the proper precautions and test your floor afterwards in multiple areas to make sure the etching was adequate. Here is an article on acid etching vs. grinding for the home owner that you might find helpful. It also has a link about how you can grind a floor yourself fairly inexpensively.

As far as the drywall getting wet, it's always a good idea to protect it when using water and chemicals. You can buy the cheap thin mill plastic drop cloths and just tape them up the first few feet of your drywall.

 

[shiers69]

I'm planning on using the product from epoxy-coat.

I have no idea what type of sealer is on my garage floor but so far I've spent about 20 hours grinding away with the floor grinder that home depot rents out and I still don't think I've penetrated the sealant everywhere yet.

On my first pass with the grinder it ended up shooting out lots of little balls of a plastic-like material. I sucked all of them up with my vacuum as I went. After the first pass I did a water check and found that water still beaded up on top of the concrete. Subsequent passes with the diamond grinder no longer produced the little balls of stuff, but the grinder didn't seem to make any headway in grinding down the concrete - it just seemed to slide across the top - even if I left the grinder in the same spot for extended periods of time. I've rented the tool twice now and have spent just shy of 20 hours grinding away at my 644 sq ft garage floor. I'm amazed my arms haven't fallen off yet.

I did use a 4.5" dewalt double-row diamond grinder to get around the edges and on the surfaces of the concrete stair into my house. It worked quite well but I wouldn't want to do my entire garage with it - I'm too concerned about screwing it up and leaving high/low spots.

I did a test spot with the phosphoric acid that came with my epoxy-coat flooring kit and it seemed to have no effect - this leads me to believe that I'm dealing with a polyurethane coating.

I'm not sure what to do next.

Option 1 (Cheap): I could use muratic acid followed by a hose down followed by a pressure wash.
Option 2 (Expensive): Acquire some solvents to remove the urethane (Does anyone have any experience here?)
Option 3 (Expensive?): I could find another grinder at some other rental store.
Option 4 (I might have to kill myself): Drop another $120 and rent the
grinder from Home Depot for a 3rd time and spend another 20 hours on my feet grinding away.

Thoughts and opinions?

 

[nolimits76]

I'm not a floor guru, but what would it cost to hire out a pro to grind the floor? Might be a better option at this point, depending on cost.

FYI, be careful with muriatic acid. I had a pool and used that stuff. All sorts of "be careful, or you will die" warnings on it.

 

[bob_mp]

Grind.

I rented a grinder with a diamabrush on it from Home Depot and ground the floor wet. I had a helper with a hose and the shop vac getting the floor wet in front of me and rinsing and vacuuming the floor behind me. Suggest doing it in sections of about 100 square feet or so. The whole process took 3-4 hours, including going back over it a second time to rough up the low spots and giving it a final rinse.

No chemicals, no dust. Just remember to empty your shop vac out before you start.

Be careful if you are using oiled-felt expansion joints. If they stick up proud, they will get shredded and smeared. I roughed up a few hard-to-reach spots with a hand sander.

Apropos covering the drywall -- I have a perimeter foundation that sticks up 6-8 inches. Nothing got on the walls.

Bob

 

[AlphaGarage]

Most of our DIY client acid etch, and that's worked very well.

In fact I can recall only a single case where our primer (BondTite 1101) delaminated from the concrete, and that was a pro contractor who did a grind, and then acid etched. Problem was that the grind really opened up the concrete, it really soaked up the acid, and he didn't neutralize it well before coating.

We never suggest to both grind and etch, and he was a pro, so I was a bit surprised by his error.

BTW, for that same we also do not recommend that you rinse an acid etch with a pressure washer, doing so can drive the acid too deep into the concrete. Just flood with water and use a baking soda/water solution to help neutralize the floor.

So grind or etch, don't do both, and if you etch be sure to neutralize.

As always I can only speak for our product line, be sure to check with your material supplier for specific guidance about their products.