Any concrete experts in here? Or contractors that are familiar enough with concrete?

Teal Terminator

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My dad just had this awesome pole "barn" built and he's super happy with how everything came out except the concrete floor. It's been down now for probably around a month and I think it looked like the pics below after just a day or two of curing. But something isn't quite right and the GC knows it, and I'm sure the guys that poured it know what happened, but at least from what is being relayed to me via my parents, they aren't saying exactly what went wrong. They are trying to fix it with sanding but apparently they went over it today and it still kinda looks like shit.

Anyway, below is what it looks like (sorry, these are the only pics I currently have). There is not water or moisture on the floor, it just appears that way. My dad said it looks like it has pools of water all over but it isn't uniform, there appear to be dips and rises throughout the floor. I figured I'd just throw this up here and see if there were any contractors or concrete guys that could give me their two cents. I don't know the exact "specs" on the concrete other than it was a higher grade/strength (6000 psi comes to mind but not sure that's correct).

Thanks for any input,
Ryan

Floor1_zpsa2ae6a41.jpg

Floor2_zpse68675f9.jpg

image_zpsb333fbd2.jpg
 
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black4vcobra

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I assume that is the finished concrete and they didn't put any sort of a sealant on it, correct?

Clearly they screwed up on the finish. Interior concrete finishing involves "fan type" power float and it has to happen after hydration (hardening) starts but before it's too far along. It takes more skill than a brush finish for outside concrete. Is it a reputable contractor that performed the work?

6000 psi compressive strength would be ridiculous for a slab, it's probably 4000 psi which is still an upgrade over what you would normally see for a slab.

It might be helpful to get a mix design from the contractor or ready mix company and see what the aggregate size is and if they put any ad mixtures in it.
 

Teal Terminator

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As far as I know, yes, that was the finished concrete without any type of sealer.

They did use some type of machines that they rode on top of (I think that is the power float you are referring to) to finish it. Not sure when relative to when it was poured though. And yes, the contractor is reputable. My dad went and saw several other completed "barns" that this guy/company had done before hiring them to do the job. I don't know if the GC used the same concrete company he always uses but I would assume so.

I could be wrong on the compressive strength but you have to know my dad. Whatever was recommended he would want to go at least one step above that. And for reference, if it matters, "barn" is 60'x70' (I think) and is was mainly built to store an RV/bus and then a couple vehicle, a tractor or two, and equipment. Not that anything other than the RV really needs more than "standard." But he was worried about cracking/etc and I am fairly certain he had them lay steel beams down the length of the building where the RV would drive over and be parked. Then the concrete was poured over and around the beams. I know many folks said the beams were over-kill but like I said, you have to know my dad, lol.

I'll have to ask him if he has the mix design from the GC or concrete folks. Thanks for the input.
 

zporta

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It is hard to tell from your pictures but it looks like there is some sort of sealer on the concrete due to the sheen on it. As far as the finish it appears that they waited too long to start the finishing process, the concrete could have set up to fast and got away from them. So instead of the machine completely leveling off the floor and knocking down the high spots and removing the majority of height variations it just scrubbed down the high spots.

But like i said its hard to tell from these pictures. When we finish a garage by hand we put three "hits" on it. The first time gets all the lines out of the slab left by the bullfloat and removes most height variations knocking down the high spots and filling in the low areas. Then the next two hits are done when the concrete is getting much harder to smooth it out to a mirror like finish.

If you can get more/better pictures it would be easier to tell.
 

5spd07gt

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It is hard to tell from your pictures but it looks like there is some sort of sealer on the concrete due to the sheen on it. As far as the finish it appears that they waited too long to start the finishing process, the concrete could have set up to fast and got away from them. So instead of the machine completely leveling off the floor and knocking down the high spots and removing the majority of height variations it just scrubbed down the high spots.

But like i said its hard to tell from these pictures. When we finish a garage by hand we put three "hits" on it. The first time gets all the lines out of the slab left by the bullfloat and removes most height variations knocking down the high spots and filling in the low areas. Then the next two hits are done when the concrete is getting much harder to smooth it out to a mirror like finish.

If you can get more/better pictures it would be easier to tell.


Zporta knows his concrete. He poured the floor in my brothers pole building and it turned out great.
 

blowngt

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I've worked in the ready mix concrete business for 21 years now (man time flies!!!).

There was something introduced during the finishing process to produce that shine you have there.

Quickest way to find out if there is a sealer is to pour some water on top (you don't need a lot). If it beads at all you've got your answer.

Very difficult to tell much more from those pics........
 

thebestofindica

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That is definitely not a mix-design issue. It appears to be a terrible cure/seal job. They obviously know what they did. They will respond or not get paid.

As for the "beams" under the concrete, are they actually steel beams? This could actually induce differential settlement and create cracking issues, rather than reduce it as I'm sure was intended. Concrete slabs on grade rarely fail due to shear from thickness issues. Almost all cracking/failures are due to sub grade issues. By placing steel beams in the slab, you are actually sending concentrated loads into the soil, rather than letting the area of the slab distribute the load evenly over the subgrade/sub base.

I'm a registered professional engineer. If you have any other questions, feel free to ask.
 

zporta

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It would be hard to believe they laid steel beams in or below the concrete. Maybe they used steel rebar and dug grade beams.
 

stroked mach

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it is sealed they do it right after they get done I always wait a day, but the prob loks to be in the top, the finish looks like it could have been done a lot better butit all comes from how good they thought it should have looked , yes it could have been done better but they prob thought it would have been good for a garage or barn, some times the guys do to much thinking lol ,but yes the finish should be up to a better standers and so should the seal job, but it looks like it will be fine it wil all crack in time
 

thebestofindica

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it is sealed they do it right after they get done I always wait a day, but the prob loks to be in the top, the finish looks like it could have been done a lot better butit all comes from how good they thought it should have looked , yes it could have been done better but they prob thought it would have been good for a garage or barn, some times the guys do to much thinking lol ,but yes the finish should be up to a better standers and so should the seal job, but it looks like it will be fine it wil all crack in time

That, my friend, is an impressive sentence.
 

Junior00

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That, my friend, is an impressive sentence.

Clearly it deserves a 9.0 with slight deductions coming from improper punctuation, capitalization, sentence structure, and spelling. If it didn't contain so few errors, I would concur and give it a 10:-D
 

Teal Terminator

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OK, I added one additional photo up top (the last one). I think those are the only photos my mom took before they came back out and did any additional sanding to try and make it better. Their biggest complaints are that it just looks messy and non-uniform in color/texture and that the surface of the concrete is not flat/smooth... has hills and valleys. I'm not sure that last pic illustrates the hills/valleys as well but it does show the non-uniformity of the concrete and/or sealer.

thebestof, turns out I was wrong... my dad had talked about putting beams in the concrete but they ended up not doing that. I didn't get any additional details but I suspect it is because the GC or an engineer thought the issues you brought up might arise.

And my mom said they did put a sealer on top of the concrete the day the poured it.

My dad is looking into epoxy's now, to at least make the finish more uniform, but I think he's going to find that will be very pricey on a building of this size. And I don't think the GC or the concrete folks are going to eat that kind of cost to make the customer happy. Apparently they didn't understand he wanted it to look similar to a Lowes or Home Depot type of floor. I'm not sure what that means they did or didn't do differently or maybe it's just an excuse at this point b/c something obviously didn't turn out quite right. Looks to me like it just needs to be sanded down to where it is a flat surface (although I imagine now that is a lot easier said than done, compared to when it freshly poured) and then either, smoothed, sealed and/or just left as a "rough" surface if that's what my dad would prefer.

Thanks again for the input.
 
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zporta

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Lowes and Home Depot get there floor polished. Which could still be done. But you can't achive that marble like finish just from hard troweling. I bet epoxy would make the uneven areas of the floor stand out even more.

I would recommend having someone use a diamond grinder on the entire slab and get it polished
 

Teal Terminator

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I would recommend having someone use a diamond grinder on the entire slab and get it polished

I think that is what my dad wants done. Just not sure they are willing to do it at no cost at this point. And I agree, I don't think he wants the epoxy done unless it is flat. But I don't really think he will get it epoxied.
 

zporta

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They might cover the diamond grinder due to a poor finish but i know they wouldnt cover the polishing. No one should expect a polished concrete look unless they get it polished.
 

Teal Terminator

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I don't know that he necessarily cares if it's polished or not, just wants it flat/even and a uniform color/texture. I don't know exactly what their agreement was from the get go... I don't think polishing was part of the deal. But this isn't what was in the other buildings he looked at by the same company. And I think they agree something isn't/wasn't quite right. It's just a matter of who's going to give what to make it right. It sucks b/c he has been super pleased with everything else and unfortunately the floor was one of the finishing touches and it's not right. They'll get it worked out I'm sure.
 

AintShePurty

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dads been doing concrete high-rises in san diego for over 30 years now. had him take a look and automatically said this is from "burning" the concrete in with trowel machines which was my guess but I knew he'd know for sure. Basically going over and over....and over and over concrete with the troweling machines (like you stated they used) until the concrete becomes dark (almost black looking) and very slick and shiny. I've worked with him for over 13 years now as well, and sealer is never applied the same day the concrete is poured. It has to cure before you can seal it. If anything, they used what we call "cure" go figure. The stuff we use is white and somewhat milky and sprays on just as a sealer would. This only helps it cure faster, at least in our case. Being that we do commercial work and such, we're on a schedule so we cant just wait for this stuff to dry normally like you could at home. Literally the next day, theres huge wall forms, tons and tons of rebar and other building materials being set on the very same deck we poured just the day before. Its gotta be cured and strong enough to withstand all of that ASAP. As for using water to tell if it has been sealed, it wont do the trick this time as when the concrete has been burned, its not as absorbent as regular concrete would be because of how much its been troweled. I was just working in a buddys garage this weekend with burned floors actually. Tranny had a huge leak in my dads 55 that we didn't know about, and none of it absorbed into the concrete. It was all there the next day puddled up. So although I agree the floor looks uneven, and i'd be p/o'd about that, being burned can be a good thing for a garage in some cases. I guess it just depends on what you prefer. Sorry about all the grammar and spelling mistakes, im at work as we speak and only got a small break. Good luck with that though! Def take a diamond wheel to it and at least level it out. Peace
 

Teal Terminator

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Thanks for the input Aint. I passed what you had to say along to my mom in an email. Apparently my dad just really doesn't want to talk about it at the moment, lol. I imagine the concrete guys know exactly what happened and either just aren't saying. Or maybe there was some genuine confusion about what they thought my dad or the GC wanted. Either way, the customer ain't happy and the floor is kinda like final piece of the big beautiful project and I think it needs to be fixed and ASAP. I know my dad is very anxious to start moving things into the barn but of course doesn't want to until this whole floor debacle is worked out.
 

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