seeking advice from concrete experts

I’m in the middle of a house build on a slab with hydronic radiant floor heating and have developed a bit of an artsy wave pool effect in the concrete. I would sure appreciate any insight members might have on this. The slab was poured August 2nd, so about 6 weeks ago. It is a thickened edge slab with pex tubing, and 2 inch blue foam underneath. Everything looked good to me (I don’t know crap about concrete) up until yesterday. I went up to check things out and found humps, dips, and waves in the concrete. It just looks so strange to me and I don’t know what to think. The contractor hasn’t seen it yet other than photo’s I’ve shared, and he’s at a loss as well. What do you all think?

Can concrete move that much after 6 weeks without cracking?

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Sorry for double post. Both attempts said the site had “timed out”, but apparently actually worked.

Whoa that’s bad. I’d get your concrete guys out asap. That would be torn out and re done if it were my house. Not acceptable

Bearcat89 wrote:

Whoa that’s bad. I’d get your concrete guys out asap. That would be torn out and re done if it were my house. Not acceptable

I agree! I dont know squat about concrete either, but I would wonder if there was something off with the mixture itself? Seems odd to take this long to begin looking like that I think.

We’re a month or so out on a build with a completely different foundation(ICF). Either way, there’s a 0% chance that would fly or anything like it. I’d get the guys out there asap as well as they’re busy. Stay on them and expect them to make it right in a timely fashion.

Concrete guys have more work than they can handle in many areas right now with a shortage of workers. We are choosing to pay substantially more than another bid for a local contractor who we know, have seen work, and lives a couple miles down the road in hopes of no issues arising.

Do they have the radiant tubing pressurized? Maybe it sprung a leak during the pour and that’s what caused that mess.

Its like you had Gophers under there while the concrete was wet. LOL Keep us updated. Not good

Eelpoutguy wrote:

Do they have the radiant tubing pressurized? Maybe it sprung a leak during the pour and that’s what caused that mess.

I’m going to guess this is probably correct and it will become a complete sh!! Show to get the plumber or concrete guys to take fault

If the contractor says anything about grinding smooth , please make sure to shoot them down.

Bearcat89 wrote:

<div class=”d4p-bbt-quote-title”>Eelpoutguy wrote:</div>
Do they have the radiant tubing pressurized? Maybe it sprung a leak during the pour and that’s what caused that mess.

I’m going to guess this is probably correct and it will become a complete sh!! Show to get the plumber or concrete guys to take fault

This was my first thought as well. I just can’t understand how it could have looked good for 5-6 weeks and now all of a sudden it’s changing shape. Anyone ever seen this before?

Also; it’s not in just this one spot. The majority of if is in the picture, but I’ve got random softball to basketball sized humps scattered throughout this 20 x 46 ft room. Would that still lead you to believe it was breaches in the pex tubing? Any idea how to get a legal expert opinion on this in case the contractors start pointing at each other for blame?

I’ve seen this when my old boss ordered interior mix for a exterior driveway. But nothing from your exact situation

I would get the supplier,concrete guy, plumber,and general all there at same time for a meeting. you need answers.

Do you know for a fact that they used high compression foam? I’ve seen basement floors go wavy when regular foam board is used. If that was the case and it’s standard density foam, it all needs to come out

gregory wrote:

I would get the supplier,concrete guy, plumber,and general all there at same time for a meeting. you need answers.

100 percent. As well as some one from the concrete mix company. ( cemstone, aggregate industry, knife river, or who ever dispatched the concrete in the first place) they will be able to tell you immediately if it was there batch of mud

Bearcat89 wrote:

<div class=”d4p-bbt-quote-title”>Eelpoutguy wrote:</div>
Do they have the radiant tubing pressurized? Maybe it sprung a leak during the pour and that’s what caused that mess.

I’m going to guess this is probably correct and it will become a complete sh!! Show to get the plumber or concrete guys to take fault

On every pour I’ve seen like this, the plumber has had the system pressurized with a gauge installed to monitor it. I would think if there was a leak, they would’ve noticed it right away. But, who knows? Even now they could check it to verify that is or isn’t the issue.

If that concrete looked good for weeks and then started change, than I’d say it’s a concrete mix issue. I’ve never seen any concrete do that.

The system was pressurized during the pour, but I wasn’t there, so I don’t know if they had any issues and had to fix leaks. It had been pressurized for 2 weeks before the pour as well.

I know they used blue 2 inch foam underneath, but never looked to see if it was “high compression” foam. That’s something I will ask my contractor.

I hope if it did have a leak the concrete guys didn’t fix it. (duct tape doesn’t last forever)
Check the gauges.
My first call would be to the Masons.

FYI – it doesn’t take long for concrete to set-up, however it NEVER fully cures.
So yes, IMHO it could have happened 5 to 6 weeks later and I wouldn’t be pulling in an Attorney quite yet.
Give the Contractors a chance to make it right.

Eelpoutguy wrote:

I hope if it did have a leak the concrete guys didn’t fix it. (duct tape doesn’t last forever)
Check the gauges.
My first call would be to the Masons.

FYI – it doesn’t take long for concrete to set-up, however it NEVER fully cures.
So yes, IMHO it could have happened 5 to 6 weeks later and I wouldn’t be pulling in an Attorney quite yet.
Give the Contractors a chance to make it right.

Thanks for your insights EPG. The pressure gauge has been removed and the Pex tubes have been hooked up to the manifolds already. I suppose it could be pressurized again for a leak down test? Would the pressure leak down if there was a line leak, but now encased in concrete?

I just spoke with the General and he shared my pictures with the concrete contractor. The concrete guy admitted blame and said it is for sure 100% really bad finishing work and that it has been there from day one. He is willing to fix it. I just don’t know enough about this stuff to know if I should let him try to fix it or if I should looking into it further?…….

Whoa. Thats some ones finishing ? I would have never guessed

I’d either find someone else to do it completely, or only allow them back with your general there as quality control. I’d also have a candid conversation with my general asking about his experiences with this concrete subcontractor and their other subs…mainly how they chose this person. Be sure that money isn’t being paid out until this is made right. There are a lot of shady people in the world who don’t care about their reputation as long as the money keeps coming in.

Tough start, but luckily it sounds like you’ve got a handle on getting it fixed and someone admitting fault.

I thought is also looked like a crappy finish job or possibly it was raining and they put a tarp on it while it was still wet. Never seen concrete get waves like that after it has hardened. Curious to hear how they can fix it now. Grinding?

I’m meeting with the general and the concrete contractor this afternoon. The concrete contractor immediately accepted blame and wants to fix it on Friday with the general there and the flooring contractor there to make sure it’s up to his standards. I”m still skeptical this was there from day one and really think I would have noticed it sooner. The concrete contractor is very upset with his crew (and himself for not reviewing their work) and says they had to have known 100% this was a big problem when they walked away from the finishing work.

Unfortunately, the money went out with the first draw since the concrete was poured 6 weeks ago. I just hope it really was finishing defect and they can fix it with no further issues down the road.

bzzsaw wrote:

I thought is also looked like a crappy finish job or possibly it was raining and they put a tarp on it while it was still wet. Never seen concrete get waves like that after it has hardened. Curious to hear how they can fix it now. Grinding?

Yes, they want to grind it, but it’s not all high spots, there are some valleys too. I will ask them how they plan to deal with that.

That is good that they are owning up to it. Sounds like a reputable guy thus far. Keep us updated!

to_setter wrote:

<div class=”d4p-bbt-quote-title”>bzzsaw wrote:</div>
I thought is also looked like a crappy finish job or possibly it was raining and they put a tarp on it while it was still wet. Never seen concrete get waves like that after it has hardened. Curious to hear how they can fix it now. Grinding?

Yes, they want to grind it, but it’s not all high spots, there are some valleys too. I will ask them how they plan to deal with that.

I would not accept a grinding job. Nor small patches in low areas. Not acceptable in your home. You paid for properly poured concrete and you have the power

You have a GC running the show!?

I’d be having some not so nice words with him.

I sent a link to my buddy that knows concrete. His response:

Was never screeded properly or bull floated. They just hand troweled it to late.

Thick carpet pad will fix everything.