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Slab poured incorrectly

OP
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Just a comment/question
You had a very good question on the integrity of the slab and were unsure of it will get a passing grade from the AHJ
and yet it seems that the prefab garage is in place.
Is there still a question on the slab or am I missing something?
No. You aren't. That the building is already placed is a big part of the problem!
 
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BillK

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So it looks like they did not pour to the top of the forms ? I dont do a lot of concrete but I have done a complete driveway and also my 2 car detached garage and I have never heard of doing it that way ? As far as I know the forms are what you use to "screed" the concrete to the finished level before you trowel finish it ??? Strange.

Has the inspector been out to look at it yet ?
 
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OP
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So it looks like they did not pour to the top of the forms ? I dont do a lot of concrete but I have done a complete driveway and also my 2 car detached garage and I have never heard of doing it that way ? As far as I know the forms are what you use to "screed" the concrete to the finished level before you trowel finish it ??? Strange.

Has the inspector been out to look at it yet ?
He told me today on the phone (when he didn't show originally) that he won't come when the slab doesn't match the plan because that is an automatic fail, and that instead I should get the engineer to sign off or devise a remedy.

He's nice enough, but sees his job as pretty much just checking boxes it seems. So, I don't think I will get much help there, unfortunately.

And no, they didn't pour to the top of the forms. They also took the forms off that night, which I was surprised at, but I know next to nothing about concrete except setting fence posts.
 

FMB4

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He's nice enough, but sees his job as pretty much just checking boxes it seems.
Yep, that's how it is. Code requires an expansion tank plumbed into a water supply? Yes. Is there an ET? Yes, check box. Is the expansion tank sized to meet the demands of the property? No. There's no box to check that very important question. Next.
 

billconner

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Not pouring to top explains it, and makes me look sideways. Maybe they didn't order enough mud.

It seems the building official does not accept it, so contractor has little to push back and has to fix it. And you deserve the 6 or 8 inch clear from grade. I go back to the apron/splash block concept. But up to designer to propose a solution, not you luckily.

Thanks for reporting. Useful learning to know how it went.
 

ConCretin

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Well I'm afraid I'm back to being concerned. It appears your sketch was more accurate than my assumptions after seeing pics of the formwork. Sorry bout that. I guess I also missed the fact that the structure was already in place.

In addition to the questionable foundation, I don't like how close the structure is to the surrounding grade and it doesn't appear you can lower the grade much without creating a low spot for water to pool.

It is a big job to address both the structural and drainage issues. The building really needs to be lifted onto some type of curb wall and at a minimum, the foundation needs to be reinforced. It could take awhile to happen but the building will eventually fail if left as is. I hope you can get some relief from your contractor.
 

PCustoms

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Is there an engineered plan for the concrete?

Was an inspection of the concrete required?
 
OP
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Well I'm afraid I'm back to being concerned. It appears your sketch was more accurate than my assumptions after seeing pics of the formwork. Sorry bout that. I guess I also missed the fact that the structure was already in place.

In addition to the questionable foundation, I don't like how close the structure is to the surrounding grade and it doesn't appear you can lower the grade much without creating a low spot for water to pool.

It is a big job to address both the structural and drainage issues. The building really needs to be lifted onto some type of curb wall and at a minimum, the foundation needs to be reinforced. It could take awhile to happen but the building will eventually fail if left as is. I hope you can get some relief from your contractor.
Thanks for all your time to reply.

When I near a remedy, I will update.
 
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PCustoms

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The poor grading covered the issue.



Thanks for all your time to reply.

When I near a remedy, I will update.

Was your slab required to have an engineered plan, and an inspection to that plan?

The building should NOT have been placed on the slab if it needed an inspection, as it should have failed.
 
OP
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Was your slab required to have an engineered plan, and an inspection to that plan?

The building should NOT have been placed on the slab if it needed an inspection, as it should have failed.
Someone from the city checked the depth and reinforcement of the footings. There was no inspection after the pour. I don't think one was required. No one has mentioned one being required to me, and I think the inspector would have said something.

Yes, an engineer had to submit drawings to be approved by the city for the slab. The work does not look like the drawing.

(Apologies for my mistake in using the reply feature above.)
 
OP
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I said I would come back with an update, so here I am for those interested.

After many months of back and forth and a great deal of stress, as well as the mason trying to tell me that the issue was only a grading problem and even coming out and covering up the problem with dirt (and essentially lying to the building office), the foundation has failed inspection. The local building official has required that the builder pay for a site visit by the engineer that did the drawings to evaluate structural integrity and propose necessary fixes.

I have also noted in the meantime that the anchor bolts protrude from this "ledge" about half an inch in at least two places, perhaps more when the perimeter is excavated. So I can reach under the slab and grab the bottom of the anchor bolt with my fingers. What a mess!

I will post another update when the engineer visits next weekend.
 

pizza

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not much of a silver lining, but the story is at least interesting and entertaining to us. thanks for sharing updates.

:(
 
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nadogail

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Why was the job stopped the moment you determined that the slab was not being poured in accordance with the approved plans?
 

kwb

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Didn’t they have to get an inspection before pouring the slab
Based on the pictures of the forms and the excavation if they had filled that to the top of the forms it probably would have met minimum spec. Not sure who posted it but I agree - they came up short on mud and cut corners instead of calling for another truck.

***** to pay for a short load but it sure beats the alternative.
 

brownbagg

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just pour a footer under the ledge about a foot wide and foot deep. really the building too little to have issues unless it was poured wet
 

brownbagg

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that building a dead load, its doesnt weight that much, so unless the ledge flex, like if it was pour wet and you have 1200 psi instead of 3000, the load will transfer through the whole slab, if its does flex that ledge will break off, since its only a down force, you can put a spread footer under the ledge. any equipment weight inside the bldg will be on the slab and footer
 

510ebl

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If I turn the brightness way up and squint I still don’t see anything holding that mesh up off the plastic in that pic pre-pour…

You wouldn’t happen to have pics from the day of the pour?
 

NDJ

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Did the OP mention where he's located ? Seems like an awful hefty design slab/footer for a 14x24 garage. Here in BC the code allows for a simple 4" slab for up to 592 sqft. Or wood mudsills if you can believe it.
 

FredWanaker

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terrible. Who approved the forms?
If I turn the brightness way up and squint I still don’t see anything holding that mesh up off the plastic in that pic pre-pour…

You wouldn’t happen to have pics from the day of the pour?
good catch
 

rancherbill

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Thanks, Bill.

It makes no sense to me either. Yes, it is all the way around. Yes, the slab is poured like my red marks. When I dug down the slab stops at 4.5 inches or so and my hand can get under there a good 5 or 6 inches before it touches what seems like the footer (hard to see without more digging)
The red marks IMHO is the way it should be done. You did the "drawing" and the concrete guy did it the way that is customarily done.

Having a little void is not a big deal. In my garage the slabs sit on the footing like yours and there are two piers that are set on undisturbed dirt to support the middle of each bay. I don't have cracks or any shifting.
 

Zeke

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Lots of finishers use a hook to pull the mesh up during the placement. Stumbling around on the piers is uncomfortable and the guys stomp the mesh down all around the spacers while dragging the pump hose. On a job this small, it may have ben placed right out of the truck chute. Still, same thing happens while screeding. Pull the mesh up just behind the screed and bull float it.
 

Firebrick43

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Lots of finishers use a hook to pull the mesh up during the placement. Stumbling around on the piers is uncomfortable and the guys stomp the mesh down all around the spacers while dragging the pump hose. On a job this small, it may have ben placed right out of the truck chute. Still, same thing happens while screeding. Pull the mesh up just behind the screed and bull float it.
It goes right back to the bottom, they are standing on it when they pull it up. My father tore out a lot of concrete pads over the years with his excavator. I never saw any of them that didn't have the mesh mostly on the bottom of the concrete. They may of had some here and there up in the middle, but for 80 percent of the slab it was at the bottom.
 

rayra

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The poor grading covered the issue up. I don't think on purpose...
No, that was done completely on purpose, to cover up the deficient form / slab pour.
What I don't get is how the building was put on it before inspection. Or the dirt graded right up to it, before inspection.
Pulling forms off same day is common. After several hours the concrete isnt going anywhere.
Of greater interest to me was the time interval between the pour and the building going up on it? Did they wait all all for the concrete to cure / strengthen significantly?

I can think of an easy fix, costly to your contractor, but don't know if your locale will pass the inspection. Re-excavate the sides of the foundation, expose all that garbage overhang, drill and dowel - with epoxy - all over the sides of that first pour and re-form to the outer top edge of the existing slab and pour more concrete to fully support the outermost dimensions of your slab.

But your inspector probably won't approve it. And it may even require total replacement to pass.

Everybody failed. You, your prime, your foundation sub. It's a complete shitshow. And it is probably going to take a long time and a court and a lot more money out of your pocket to remedy.

Your foundation guy dug the trench wrong, improperly formed outside that perimeter trench, then shorted the thickness of the slab, either not enough concrete so he could pocket a ~$1000, or wound up way short on the calculated volume due to his terrible prep. I'd be surprised if the garage slab is even sloped the way it ought to be. No concrete professional would form above the top of the slab, the form is part of the screeding process. Unless there were some extenuating design circumstances and your garage is a simple thing that has none.

And then after it was done poorly - and there is no way your general / prime could have missed that it was wrong - the dirt was shoved up against it trying to hide it. Lawsuits for everybody, if your prime and inspector cannot come to an agree on an acceptable fix AND your prime eats the cost of that fix.
 

rayra

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To anybody else reading - the OP is already screwed - it is on you to get at least a modicum of education on what are and are not appropriate building practices. It is YOUR hard-earned money and time at stake. A few nights on YouTube and frequent time on-site at the end / beginning of each phase, photodocumenting EVERYTHING. Asking questions. Stopping the work of YOUR employees, if necessary.

FFS, we have the entire universe of human knowledge and an HD video and still camera IN OUR HANDS, all day long.

And run from any prime that wants you to just sign a check and stay away. Because THIS is the kind of garbage result you are chancing by doing so.

/Like that poor sap with huge plans for an expensive lift to store his collector cars elevated and let his prime build his garage too shallow to do so, under his shiny new house.
 
OP
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Their engineer came out. He says it is structurally sound, a light building. He proposed a fix of digging down around perimeter and pouring concrete to extend the perimeter vertically down below grade.

Then he says to dig below grade to meet height and drainage.

4 inches off grade, plus 4 to meet plans, plus drainage means we will have a 6 to 8 inch or more trench around it. That won't work. Not what we contracted for and will harm trees and create ongoing drainage issues.

Questions for those here who know:

The mason did not get a backfill inspection. Is one required on a 12x24 monolithic slab at frost depth? Seems like it is to me under NJ UCC code. Thoughts? It goes 42 inches down if that matters.

What would the total height of the top be off grade if the plans called for 8 inches from the grading slope? That is, am I correct to think the height from the original grade would need to be 8 plus the additional height to meet the 6 inch over first 10 feet requirement for drainage? And if the floor slopes toward the garage door the rear of the building would also need to be that slope amount of grade so 8 plus drainage slope plus floor pitch slope?

The top of this foundation is 4 inches off grade in the front and 6.5 in the back and I am trying to figure out how much it is short from what should have been done. And when I say 4 off grade, I mean the original grade so if it was graded to drain it would only be..2 or less above the dirt.

Also, that ledge might be strong enough for the building, but 3hat about cars driving in and out? Could it snap off in the front?
 
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