Polished concrete

[sbelles]

They will be pouring the floor of my garage https://www.garagejournal.com/forum/showthread.php?t=404179&referrerid=365528

next week. I will be doing race car alignments and some welding so I need it smooth and flat and epoxy is out. I've told the builder that I intend to polish it.
Besides making it flat and smooth (they did a very nice job on the attached garage floor), is there anything else (additives etc.) that I should ask about? What about after polishing?

 

[ConCretin]

The only additive I would suggest is a mid range water reducer, which will provide a 5 or 6" slump with less water than a traditional 4" slump. The mix will be workable but will bleed very little, which will help provide a good surface. Give the guide in the link below for some additional things to consider.

Btw, I've been enjoying your other thread. Very cool place you have there.

 

[JoeMcGov]

You want the poured slab FLAT FLAT FLAT to maximize the consistency of the polished finish.

Have you selected the person/people who will do the polishing? You want to understand their expectation BEFORE you pour the slab.

 

[sbelles]

The only additive I would suggest is a mid range water reducer, which will provide a 5 or 6" slump with less water than a traditional 4" slump. The mix will be workable but will bleed very little, which will help provide a good surface. Give the guide in the link below for some additional things to consider.

Btw, I've been enjoying your other thread. Very cool place you have there.

Thanks, I've enjoyed your build as well. I first saw it about five years ago. My wife is a Mainer originally so we spend a lot of time there. I haven't had time to read through everything posted in the past few years but I'm looking forward to it.

 

[sbelles]

You want the poured slab FLAT FLAT FLAT to maximize the consistency of the polished finish.

Have you selected the person/people who will do the polishing? You want to understand their expectation BEFORE you pour the slab.

My builder has been coordinating the two since I'm not there most of the time but I'm heading up tomorrow and meeting with the builder. I'm hoping to speak with all three parties in the next few days. Preferably together.

 

[Aerospace Eng]

Not really additives, but I have seen some polished floors where people put some small parts (chips at an electronic company, etc) in the upper layer. When the floor is polished it looks like a modern art version of a fossil table.

 

[mx500]

We have that in some high schools in michigan and it looks awesome

 

[Garage Flooring]

They will be pouring the floor of my garage https://www.garagejournal.com/forum/showthread.php?t=404179&referrerid=365528

next week. I will be doing race car alignments and some welding so I need it smooth and flat and epoxy is out. I've told the builder that I intend to polish it.
Besides making it flat and smooth (they did a very nice job on the attached garage floor), is there anything else (additives etc.) that I should ask about? What about after polishing?

I would make sure they understand exactly what you are looking for. Power troweled vs grind and polish two completely different things.

 

[RPH]

Grind and polish is a very expensive option. When I considered it the price was $7.00 per square foot. Ghostshield at that point.

 

[sbelles]

I talked to the masons and my builder today. They have talked to the polishing guys so I think they are on the same page. The only problem is, they tell me that either the whole thing is flat or none of it is so they can't put any slope to the floor drains in bays 1 and 3 if I want bay 2 to be flat. Oh well, flat and smooth is the important thing. I have to squeegee water into the drains in the attached garage even though it's sloped.

 

[sbelles]

Grind and polish is a very expensive option. When I considered it the price was $7.00 per square foot. Ghostshield at that point.

Was that just for the finishing or did it include the pour?

 

[Aerospace Eng]

I got quoted $5 to $7 per foot just for polishing, with the bigger the area the cheaper it went.

I decided to paint the floor, which was about $1 per foot in paint, with another $0.50 per foot with rental of grinders, prep materials (cleaner, acid, neutralizer), and consumables (rollers, trays, etc.). I did it myself, but the labor on a 2000 sw ft floor was a good 40 hours.

 

[yeldogt]

Was that just for the finishing or did it include the pour?

The price I got was also expensive -- this was for a high end interior

 

[Aerospace Eng]

They will be pouring the floor of my garage https://www.garagejournal.com/forum/showthread.php?t=404179&referrerid=365528

next week. I will be doing race car alignments and some welding so I need it smooth and flat and epoxy is out. I've told the builder that I intend to polish it.
Besides making it flat and smooth (they did a very nice job on the attached garage floor), is there anything else (additives etc.) that I should ask about? What about after polishing?

Out of curiosity, why is epoxy out?

 

[sbelles]

Out of curiosity, why is epoxy out?

Welding slag will burn it.

 

[sbelles]

Well, apparently they had a meeting after we talked and they now say they can do a 3' radius slope around the drains and still make everything else flat. That will help to drain it.

 

[RPH]

No pour costs, just grind and polish.

 

[Falcon67]

I will be doing race car alignments and some welding so I need it smooth and flat and epoxy is out.

Flat all across. That's how I did my first shop. And what's the BS about welding and no epoxy? I had the polish the **** out of the floor with the paddle wheel, so much that you had to be careful walking across it if it was wet. Etched that and coated with epoxy, great floor. Welded on it, etc - no issues. As noted, buy a squeegee. Same with the new shop - it was supposed to be flat. Part of it is, one of the trucks was late to part isn't. It was also buffed, etched and painted. I won't have a shop floor that isn't covered with a coating.

 

[Armorpoxy]

Hi,
Our www.prep-crete.com Installation Division does hundreds of thousands of sq ft of polished concrete annually. Just make sure that your polishing company uses a proper burnished in stain blocker/guard to help with oil stains since polished concrete is not super stain resistant, hence why it is not used often in auto shop environments.

 

[Falcon67]

Welding slag will burn it.

So what. If it's a show room, don't weld in there. If it's a working shop, then plenty of other things will happen as time goes on. Or use a coating that can be renewed at some future date. Why I went with Kelly-Moore KM-15.

 

[PNWguy]

So what. If it's a show room, don't weld in there. If it's a working shop, then plenty of other things will happen as time goes on. Or use a coating that can be renewed at some future date. Why I went with Kelly-Moore KM-15.

I did a search on "Kelly-Moore KM-15" and got a yellowish color sample, but not a floor paint. Am I searching wrong, or did you put yellow latex paint on the floor? I'm interested in a repairable, reasonably priced floor coating.

 

[Vintage Veloce]

Get a 6' or 8' level and show it to the contractor. Tell them you are going to check the flatness everywhere. Agree on a spec... how big a gap you can see under the edge... 1/8"? 1/4"?
In my experience they all say it will be no problem, but break out the straight edge and the story changes. But have the discussion first so you aren't disappointed.

 

[ConCretin]

Get a 6' or 8' level and show it to the contractor. Tell them you are going to check the flatness everywhere. Agree on a spec... how big a gap you can see under the edge... 1/8"? 1/4"?
In my experience they all say it will be no problem, but break out the straight edge and the story changes. But have the discussion first so you aren't disappointed.

This is pretty good advice if you are going to polish the floor. The polishing doesn't remove enough material to level the surface buy it will accentuate any waviness. Before the industry went to profiling specs for flatness (Ff and Fl), the standard for flatness was the amount of space under a 10' straightedge. It takes a pretty good finisher to keep the gaps under 1/4 and a really good one to get them down to an 1/8.

 

[foodie]

I followed your previous thread on the building, beautiful plans, love the addition of the man cave on top. I am not a builder, concrete contractor or an engineer, just a consumer....do you just have welded wire mesh in there or do you also plan to put in rebar? Not a criticism,...just a question....

 

[Vintage Veloce]

It takes a pretty good finisher to keep the gaps under 1/4 and a really good one to get them down to an 1/8.

Here in San Diego, I couldn't find anyone who could do it or would commit to it. It was like a joke, they would say yes, yes, yes, perfectly flat, no problem... Then I'd show them the straight edge and say I was really going to check at at least 20 places on the floor and they would all reverse themselves... "oh well, we can't really do that."

PS: also understand the difference between flat and level, and use the terms properly with your contractor, and make sure they know the difference too.

 

[Falcon67]

I did a search on "Kelly-Moore KM-15" and got a yellowish color sample, but not a floor paint. Am I searching wrong, or did you put yellow latex paint on the floor? I'm interested in a repairable, reasonably priced floor coating.

Appears they changed the number or discontinued that item - will look around for it.

I have a copy of the old TDS stashed on my web site - http://raceabilene.com/misc/NewShop/KM15-TDS.pdf

I'm thinking about a small expansion so I may have to go by the local KM store with the TDS and ask what replaced that item.

Several related items here - https://north-america.international-pc.com/in-focus/devoe

 

[sbelles]

The floor was poured last Thursday. I've seen some pictures but I won't make it up there for another three weeks of so.

 

[ImSteevin]

Looking forward to seeing it!

 

[Vintage Veloce]

Revised advice: once the floor is poured, never put a straight edge on it... you may not want to know. ;-) I mean, if it looks flat, and it's done, you maybe happy enough with that. Mine looked great until I checked it.

 

[sbelles]

Looking forward to seeing it!

Me too.

 

[kumquat]

Why not epoxy and use a welding blanket at the appropriate time?

 

[Falcon67]

I finally ran across this - probably the "replacement" for the old KM-15 mastic.

https://www.rustoleum.com/product-c...e/epoxy-coatings/9100-system-dtm-epoxy-mastic

TDS - https://www.rustoleum.com/tds/9100 System_RO-51_2032990.pdf