Anyone grind concrete floors

[Sedgehammer]

We're having to grind our barndo floor due to poor finishing from our crete guy . We're running into soft and hard spots . We have a 3,500 psi floor , so the medium bond magna double discs should work . Using a Edco double disc machine electric . There are places it really turns out the powder . Others it will glaze over the diamonds , so need to use the soft bond in those areas

[farmfromkansas]

Friend built a restaurant, and they used ground down polished concrete for the finished floor.  Stuff looks like marble.

[Raider Bill]

We're having to grind our barndo floor due to poor finishing from our crete guy . We're running into soft and hard spots . We have a 3,500 psi floor , so the medium bond magna double discs should work . Using a Edco double disc machine electric . There are places it really turns out the powder . Others it will glaze over the diamonds , so need to use the soft bond in those areas

That sucks.
What did the finisher have to say about it?

[SwampDonkey]

It takes some hours for a good job and I was told it's hard to find anyone to do it. They did mine, house and garage. That's why they was hired, and they have done many. But I think my father had to rent a concrete polisher and do it himself at his house. Dad was 60 at the time, but that would never stop my old man from polishing that floor. ;D

I know it don't help none, but might as well have another account as nothing at all. ;)

[Walnut Beast]

Get it done with a shot peen machine 

[Sedgehammer]

@farmfromkansas That's the plan , but with the hard and soft spots , near impossible to smooth it all out . Can you say self leveling epoxy

@Raider Bill It wasn't his fault he said .... Was poor concrete he said .... I said we'd settle up once the slab was finished properly ...  ;D

@SwampDonkey Oh it can be found , but this guy won't find it for double what the slab cost .....  :D :D

@Walnut Beast That'll take a few peenings unfortunately ..... 

[barbender]

Sounds like maybe too much water was added. Did it get chalky? 

[Walnut Beast]

He's the one that did the concrete job. If it's the concrete then he needs to deal with it. I would get the concrete companny to come out and get there opinion. Make sure he paid the concrete company and didn't get it billed to you

[Sedgehammer]

Sounds like maybe too much water was added. Did it get chalky?

no water was added . Yup , chalky . I was told it's from working it too soon

[Sedgehammer]

He's the one that did the concrete job. If it's the concrete then he needs to deal with it. I would get the concrete companny to come out and get there opinion. Make sure he paid the concrete company and didn't get it billed to you

I buy all the material on all of my work . We've used him a lot in the past . Always was fine , but nothing that was this large or this fine of finish . he won't fix it , cuz not 'his' fault and the wife doesn't want him on the property anyways . I asked him for his insurance and bond info , but amazingly he had let it lapse

[SwampDonkey]

If I'm not mistaken, grinding is only done after 2 to 4 weeks of it setting.

I was talking about trowel polishing soon after a pour with a walk behind power trowel, like this. They can be rented near here. But the concrete contractor I use has there own. You keep trowelling until it hardens up, then you cut the slab. You don't get a shiny floor, but you get a smooth floor that you can scrub with a mob or sweep.

How to operate a concrete finishing machine (power trowel) - YouTube

I think you chose the wrong concrete contractor. You probably know as much as he does or more. :D

[barbender]

That doesn't sound right. I'm not a concrete expert, but I've been around it plenty. I've never seen it get chalky from "working it to soon." The only situation I know of where you can get ahead of it is floating it before the bleed water comes to the surface. In outdoor concrete in cold climates, that will lead to spalting. If the guy that did the pour didn't add water, something was screwed up at the batch plant. Chalky is usually too much water...what slump did the mud have when it arrived?

[Raider Bill]

I'd  have the concrete co come out and take a sample.
Sure am sorry this happened, crappy way to start a build.

[doc henderson]

I have been around a bit of concrete.  my brother did road construction all over the country and was in charge of all the concrete made for jobs.  they all had core samples for test and if they miss the mark, it is all taken out.  I would not blame the contractor till you test the concrete.  we had one bad spot where stuff just popped up on the surface.  I passed a concrete truck yesterday on my way to pick up logs, and I thought, "is that kid old enough to drive"?  lots of variables.

[farmfromkansas]

 The concrete company always blames the guy who lays and finishes the mud.  But concrete companies turn out some bad batches too.  One that  makes me sore, is when a truck comes back in with some leftover mud, and they just add to it and send it out.  The mud gets hard way quicker than it should and you have a terrible time getting it laid and finished as it is setting up while you are putting it down.  Did a basement floor like that once, by the time we got the concrete laid down it was getting hard and we just ran a power trowel over it once and it was done.  Should have time to use the trowel 2 or 3 times, helps level the slab if it is not getting hard before you can trowel it.

[doc henderson]

the bull float gets the rock down a bit so you bet a nice fine mud on the top.  If he worked it too soon or too much, maybe some slurry spots, but if he was good in the past, I doubt he would waste his time going in circles working wet mud.  You are there, and not to doubt you, but something to consider.  If a core is taken and the soft spots are throughout the core, cannot be the placement.  When we did our pool we had thick stuff that would stick and not slump on a 50° sidewall, and thin enough to level it by moving it with your rubber boots.  It had plastic reinforcement, and after 12 years and a few liner changes, not a crack and it is only 1.5 inches thick.

[Sedgehammer]

If I'm not mistaken, grinding is only done after 2 to 4 weeks of it setting.

I was talking about trowel polishing soon after a pour with a walk behind power trowel, like this. They can be rented near here. But the concrete contractor I use has there own. You keep trowelling until it hardens up, then you cut the slab. You don't get a shiny floor, but you get a smooth floor that you can scrub with a mob or sweep.

How to operate a concrete finishing machine (power trowel) - YouTube

I think you chose the wrong concrete contractor. You probably know as much as he does or more. :D

It's been 6 weeks
We used a power trowel
Prolly so  ;D

[Sedgehammer]

That doesn't sound right. I'm not a concrete expert, but I've been around it plenty. I've never seen it get chalky from "working it to soon." The only situation I know of where you can get ahead of it is floating it before the bleed water comes to the surface. In outdoor concrete in cold climates, that will lead to spalting. If the guy that did the pour didn't add water, something was screwed up at the batch plant. Chalky is usually too much water...what slump did the mud have when it arrived?

6" slump with retarder  

Several others have said that he working it too soon , it gets too creamy and you get the chalk

[Sedgehammer]

I'd  have the concrete co come out and take a sample.
Sure am sorry this happened, crappy way to start a build.

They were out . Their samples they pulled at the batch plant are fine

[Sedgehammer]

I have been around a bit of concrete.  my brother did road construction all over the country and was in charge of all the concrete made for jobs.  they all had core samples for test and if they miss the mark, it is all taken out.  I would not blame the contractor till you test the concrete.  we had one bad spot where stuff just popped up on the surface.  I passed a concrete truck yesterday on my way to pick up logs, and I thought, "is that kid old enough to drive"?  lots of variables.

Like I told Raider , they were out and they checked their samples . Looked good

[Sedgehammer]

the bull float gets the rock down a bit so you bet a nice fine mud on the top.  If he worked it too soon or too much, maybe some slurry spots, but if he was good in the past, I doubt he would waste his time going in circles working wet mud.  You are there, and not to doubt you, but something to consider.  If a core is taken and the soft spots are throughout the core, cannot be the placement.  When we did our pool we had thick stuff that would stick and not slump on a 50° sidewall, and thin enough to level it by moving it with your rubber boots.  It had plastic reinforcement, and after 12 years and a few liner changes, not a crack and it is only 1.5 inches thick.

Yup , bull floated till he could use the power trowel . Looks like he floated it too much

Core checked out

[barbender]

So you did get it cored, in the actual slab?

[doc henderson]

i do not want to get in your biz, but they need to cut a core from your slab and get it independently looked at.  they will both blame the other.

[Sedgehammer]

i do not want to get in your biz, but they need to cut a core from you slab and get it independently looked at.  they will both blame the other.

So you did get it cored, in the actual slab?

Can't do actual slab . There's pex tubing in it

You guys just trying to help , so any and all welcome

[Sedgehammer]

The guy from ediamond tooling (where we got the grinding diamonds) said that what we're experiencing is some what typical of a poorly power troweled slab . Some places are really hard from the burning in of the power trowel and other places aren't because it didn't get trowled properly