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Botched floor prep - opinions needed please

CT2012

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Oct 11, 2012
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354
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Northeast
Thinking it was good idea, I had a service come out to do the floor, and the below photos are after first pass of grinder, muriatic acid, and powerwashing. Am very disappointed with how they handled it (very sloppy and poor prep work, acid splashing ruined some other aspects of my freshly painted garage walls) and I kicked them off the job. Now I gotta figure out what's next in terms of options, and the budget is really limited to doing things myself going forward--which is ok by me.

Some spots of concrete are flat and the grinder just didn't cut through the surface, strangely enough (or the operator was lazy). Other parts of concrete have very bumpy aggregate, and it would take an 1/8" to a 1/4" or so to remove it to make smooth. The challenge with that is I'd have a very uneven floor in certain parts, assuming I could get a grinder that'd take that much off.

The muriatic acid definitely ate through some of the paint, and it flakes and scrapes off, so I'm thinking a powerwashing is due but using a surface attachment (I have a 3k psi powerwasher) so as to contain the spray and mess and go at it again. The old paint (a concrete latex from Benjamin Moore, put down several years prior by former homeowner) in its current state will just not act as a good binder for epoxy or anything for that matter, or at least that's what I think.

Assuming I can get most of the paint off, especially in the little valleys of aggregate, I'm thinking of a couple of options:

1) Skim coat with self-leveling concrete, then apply concrete paint or epoxy;
2) Leave surface texture as is and apply a strong primer and hope for the best in applying a concrete paint or epoxy; or
3) [other?]

Any tips or suggestions appreciated.

p.s. ignore the small dark brownish-colored stain on the concrete--that's some sort of impossibly and crazy hard resin that's on there. whatever it is, it's hard as anything. take a hammer to it and it doesn't even chip.







 
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jaye944

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ohh thats bad.. I'm just starting but from I think

the acid WONT eat paint, did they use too strong a concentrate;
strongest should be no more that 5:1

what are all thoes rocks? has the acid eaten the concrete away?

hopefully somone with more expereince will be along to help
 
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CT2012

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Messages
354
Location
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the "rocks" is the surface aggregate in certain parts of the floor. about a quarter of it looks like that (20x20 garage). obviously years ago when built they didn't believe in troweling it smooth....or the concrete folks had to run early to catch a baseball game....:sad:

not sure of mixing ratio on acid but it was likely around 5:1 since they used a 5 gallon bucket of water and most of a gallon container of the muriatic product.

the good news is the floor is pancake flat, perfectly level. the bad news is....parts of it look like the surface of the moon. with paint.

lovely, eh?
 
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jaye944

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Messages
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GTA, Ontario, Canada
ahh ok I would go with option 1 then

actually years ago, I had a concrete drive laid. and afer a few days something similar happened to me, looked like the surface of the moon !

Was told they probably had a bad mix or damaged by frost
 

shaun oriold1

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Joined
Oct 9, 2011
Messages
288
Location
Burlington,Ontatio
Thinking it was good idea, I had a service come out to do the floor, and the below photos are after first pass of grinder, muriatic acid, and powerwashing. Am very disappointed with how they handled it (very sloppy and poor prep work, acid splashing ruined some other aspects of my freshly painted garage walls) and I kicked them off the job. Now I gotta figure out what's next in terms of options, and the budget is really limited to doing things myself going forward--which is ok by me.

Some spots of concrete are flat and the grinder just didn't cut through the surface, strangely enough (or the operator was lazy). Other parts of concrete have very bumpy aggregate, and it would take an 1/8" to a 1/4" or so to remove it to make smooth. The challenge with that is I'd have a very uneven floor in certain parts, assuming I could get a grinder that'd take that much off.

The muriatic acid definitely ate through some of the paint, and it flakes and scrapes off, so I'm thinking a powerwashing is due but using a surface attachment (I have a 3k psi powerwasher) so as to contain the spray and mess and go at it again. The old paint (a concrete latex from Benjamin Moore, put down several years prior by former homeowner) in its current state will just not act as a good binder for epoxy or anything for that matter, or at least that's what I think.

Assuming I can get most of the paint off, especially in the little valleys of aggregate, I'm thinking of a couple of options:

1) Skim coat with self-leveling concrete, then apply concrete paint or epoxy;
2) Leave surface texture as is and apply a strong primer and hope for the best in applying a concrete paint or epoxy; or
3) [other?]

Any tips or suggestions appreciated.

p.s. ignore the small dark brownish-colored stain on the concrete--that's some sort of impossibly and crazy hard resin that's on there. whatever it is, it's hard as anything. take a hammer to it and it doesn't even chip.

So I see grinder swirl marks, in one of the pictures, but they're tiny. Were they using a hand grinder with a cup wheel? IF you grind a floor, there isnt a need to use acid, or powerwash it.

Sounds like they were bush league. Get a proper company to come in and grind it, it will take care of the unevenness, and get rid of that nasty resin too. My werkmaster would chew through your floor in 2-3 hours at an easy pace!

I did a floor for a guy recently, whose floor was 50 years old. Looked way worse than yours. Spalling, heaving, general abuse! Grinding took care of most of it, and patch filling took care of the rest. It looked as good as his friends house we did at the same time whose house was brand new. I was on the fence with putting a overly on the floor, it was more the challenge I wanted, which is why I went the route I did.

S.
 
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CT2012

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they used a crappy machine AND a hand grinder.

bush league is a compliment, believe me.
 
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CT2012

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already on site as painting contractor--for which they did do a good job.

when asked if could do flooring, answer was "sure!"

the guy they sent out (who was not on site for house painting) was new and not sharpest tool in shed.

live and learn.

local flooring specialist wanted 6-8 bucks a sq. ft. to do the floor (grind, epoxy, etc), the guys i chose were far less. got what i paid for....
 
Last edited:

shaun oriold1

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Joined
Oct 9, 2011
Messages
288
Location
Burlington,Ontatio
already on site as painting contractor--for which they did do a good job.

when asked if could do flooring, answer was "sure!"

the guy they sent out (who was not on site for house painting) was new and not sharpest tool in shed.

live and learn.

local flooring specialist wanted 6-8 bucks a sq. ft. to do the floor (grind, epoxy, etc), the guys i chose were far less. got what i paid for....

Ha. I see this all the time. A lot of the job I do are new construction custom houses. I'd say 50% of the time there is a painter working, and when I tell him I'm there for the floors he says "Oh I do epoxy too" I politely roll my eyes and go about my business. Like clockwork! 100% of the time, they are always impressed with what I do, and they always say the epoxy they get from their paint store doesnt look nearly as good as mine, as they never do chip floors. They dont grind the floor either which is the first red flag in my books!

Tough deal... I hate to see people get taken advantage of...

S.
 

skyhopsing

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Joined
Nov 7, 2013
Messages
14
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Rent one of these if you can, it will grind off everything.

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This edger is good for high spots also.

Good Luck
 
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