Concrete grinding

[iceman536]

How practical is it to hand grind a 22'X22' garage floor? Is this something that will take days to complete? Does Home Depot rent grindng machines?

Also (among other things) my floor is spalling in several places. Will grinding make this worse? Will i need to patch these areas after grinding but before applying expoxy? Or will the "self leveling" epoxy fill this in?

New here but loving this board.

 

[54FordPanel]

My garage is about 36'x24', and I did it by hand. When I ground my floor, I bought a Bosch 9" grinder I found on sale for $99 bucks, and a diamond cup grinder wheel. The wheel was $80 I think. If you got a cheap import grinder it would be much cheaper. 7" maybe, but not a 4"
It was dusty, dusty, dusty work...I had ever seen so much dust. But it wasn't especially hard work. I would easily do it again if I had another floor. It only took half a day, I think. You'll need knee pads for sure.
I would buy the tool rather than rent it. I'm sure renting it would have been close to 1/3 or 1/2 the price, and I'd rather have the tool afterwards for the extra money.
My epoxy didn't fill any of my chips and grooves. Some grooves I made with the diamond grinder by letting it sit too long in a spot...It will definitely remove concrete quickly if you let it sit. Anyway, as I've said on other posts, I way over-estimated the "filling" qualities of the epoxy. It didn't flow out and self level like I thought it would.
My recommendation is if you have grooves, holes, or chips in your concrete now, unless you fill them, you will have them after you epoxy.
I used Epoxy-Coat, and I am very happy with it. Good people.

 

[iceman536]

Should I patch the spalling on my floor? Then grind? Or grind first, or not at all?

 

[AlphaGarage]

If the spalled area are loose, then grinding might be enough to knock them off, which is probably a good thing if they're that bad anyway. I mean if it's that bead better to remove the loose stuff now rather than have it work loose and lift after you coated the floor - right?

"Sound" the entire floor, that is take a hammer and tap everywhere. If there's a hollow sound consider knocking out the loose spalled stuff and then patching it. When you go to grind the entire floor should then be good and solid.

 

[iceman536]

Maybe it is not spalled? There is no loose concrete, it is just pock marked, it is not actvely flaking away.

 

[AlphaGarage]

Maybe it is not spalled? There is no loose concrete, it is just pock marked, it is not actvely flaking away.

I'm just responding to your first post where you said the floor has spalled areas. That's why I suggested you "sound" it. Solid concrete will have a dull, solid thud, any loose spalled stuff will have a completely different sound. Some guys can tell by dragging a chain across the floor - but the hammer method will work better for you. If it's not spalled, you can ignore all of it, just patch the divots and move on to the next step.

 

[iceman536]

Just not sure the right term is "spalling", that's all.

Do I grind, then patch?

 

[TRC51]

Just not sure the right term is "spalling", that's all.

Do I grind, then patch?

Hmmmm.... walked into this conversation at an awkward moment.