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My mother hired a guy to build a 30x30 pole barn for her horses with a 20x30 pad inside, I met the contractor when he came out to give her the quote, seemed like a decent guy.
The location of the barn had about 18" of slope across the 30', the contractor originally said he was going to use a reputable dirt contractor, whom my mother has worked with before. She came home after work to find a guy in a skid loader leveling off fill that had been brought in. I raised some questions about placing a concrete pad on a fresh pad created with fill, they claimed it was "Architectural fill", which to me sounds like a joke.

After they built the barn they poured the pad, on top of the dirt pad. They did not use any rebar in the pad, they claimed they used fiber-mesh, which does not need any rebar.

Now, approximately 4 months after the pad was poured it has some pretty large cracks, and settling going on. At the crack control cuts there is a 3/4" step where the pad has settled, there are also some pretty significant cracks at different spots in the pad. To date all that has been parked on it is my mothers 1/2 ton truck, which is only there for an hour at a time.

In my opinion the contractor cut corners, they should have made a cut, rather than fill, the pad was not allowed to settle, nor was it compacted prior to the concrete work.
They also should have used rebar to tie the pad together, as far as I know fiber-mesh is not a replacement for rebar.
The contractor is supposed to come over next week while I am home to repair some of his ghetto welds on her horse stalls, I am hoping to get him to agree to repair the concrete as it has become a safety hazard for horses or people tripping over the step in the pad.

I would like to assure myself that I am correct in that "Architectural fill" is BS, as well as my above statements about the use of Fiber Mesh and rebar.
I dont think there are any building codes that apply to this, but the work was done in Colorado.
 

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Your thoughts are well within the realm of normal/reasonable.

"Architectural fill" is bullshit. "Structural fill" is a legitimate term and pertains to properly compacted fill below structural elements and/or slab on grade.

At a minimum the concrete should have had wire-mesh in it. Rebar can be overkill for a slab on grade, but no reinforcement is unacceptable in my opinion. 6x6 wire mesh is pretty much the standard for a "normal use" slab on grade.

If it were me, I would make them tear out the slab, compact the dirt(a simple walk behind plate tamper is not enough to compact 18" of loose fill, you would need at least a small walk behind sheeps foot roller), and then repour the slab with wire mesh in it.

Let us know how it goes!
 

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Really fill isn't recommended without proper compaction tests to ensure density. Did they perform a standard procter test? Proof roll? Suitable fill material? How much rock over fill?

How thick is the slab of concrete? Do you know the mix that was used? I work with civil engineers and see their specs all the time here in northeast Iowa but am not sure about Colorado requirements.
 

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the fill should have been compacted gravel...
#3 rebar on a 12"x12" grid IMO...
did deck work and commercial swimming pools off and on for 15 years...

contractor should be redoing this pad...
 

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Who cares about how they did it, they are the professionals, and a slab shouldn't crack after 4 months. It needs to be fixed regardless.
 

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The best scenario would be to make them rip it out...and give you your money back.

Failing that badly, I wouldn't let them try it again.
 

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the fill should have been compacted gravel...
#3 rebar on a 12"x12" grid IMO...
did deck work and commercial swimming pools off and on for 15 years...

contractor should be redoing this pad...
Gravel cannot be compacted because the void space is too high. I'm a PE and I give people advice on concrete all the time but they almost never listen to me and then complain when their concrete cracks.

1. Put the slab in a cut, not a fill unless you have a vibratory roller on hand.
2. Lightly spray the existing dirt with water after you cut and compact it using the best tool you have available. Something like a whacker is a bare minimum.
3. Cut a thickened edge around the perimeter of the slab so the concrete is a foot thick there.
3. Put the WWM or #4 bars on chairs. If the reinforcing steel is on the ground it's doing absolutely nothing.
4. If you pour bigger than 20'x20' without expansion joints you better have some really serious prep, a good contractor and possibly an engineer unless you love cracks.

If you absolutely have to put it in a fill section ask for road base, not sand or gravel
 

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Gravel cannot be compacted because the void space is too high. I'm a PE and I give people advice on concrete all the time but they almost never listen to me and then complain when their concrete cracks.

1. Put the slab in a cut, not a fill unless you have a vibratory roller on hand.
2. Lightly spray the existing dirt with water after you cut and compact it using the best tool you have available. Something like a whacker is a bare minimum.
3. Cut a thickened edge around the perimeter of the slab so the concrete is a foot thick there.
3. Put the WWM or #4 bars on chairs. If the reinforcing steel is on the ground it's doing absolutely nothing.
4. If you pour bigger than 20'x20' without expansion joints you better have some really serious prep, a good contractor and possibly an engineer unless you love cracks.

If you absolutely have to put it in a fill section ask for road base, not sand or gravel
What he said. My dad is a general contractor and owns his own heavy equipment company. Whenever we have done slabs that have been put on fill we import road base, compact with either a sheeps foot / pad foot compactor or smooth drum vibratory roller with no more than 6" lifts. 4" does sound rather thin for that size of a slab, especially if horses are going to be walking on it. Sounds like you need to have this guy come back and rip the slab out and give you your money back. Before you meet with him cold call his company and ask if he is bonded but don't tell them who you are. If he is, when you meet with him threaten to go after his bond and report him to the contractor’s license board. That usually carries a lot of power.

Good luck.
 

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4" is thin if horses are going to be walking on it? Are you fucking serious? I would LOVE to hear your reasoning behind this....

The problem is not the thickness of the pad. If it is truely fibred concrete, then not having steel reinforcement in the concrete is not the problem. The problem is that the slab was poured on fill. If the fill was not compacted correctly, then you are definitely going to have issues.

With all of that said, it is COMPLETELY unreasonable to think that the concrete is not going to crack. All concrete is going to crack, even if it is done exactly to proper specs. It is the nature of the beast. You control the cracking by cutting control cuts to make it crack where you want it to. If it is seperating that much at the control joints, then you have a definite settling problem. Regardless of the thickness of the concrete, or the amount of steel that was/was not used, if the ground under the pad settles, you are SOL.
 

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Fiber mesh dose nothing but control surface cracks, its dosnt replace the need of bar in a pad that thin. Should have had gravel and use of a campactor. The fact it has settled shows the grade was where the problem is.
 

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Why not get a big reversing plate compactor run it over your existing slab which will likely break up and push into the ground about 6" then pour the new slab right on top?
 

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Yeah....4" is plenty thick. We just poured a 100,000SF slab on grade at the bottom of a parking garage and it's all 4" thick with 6x6 welded wire mesh.
 

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Fresh new concrete maybe 2 weeks old now. 5" min to 7" thick, all 1/2 rebared 24" on center tied at every intersection, doweled tight into exsisting concrete slab, WITH fiber in concrete. And relief cut to match exsisting concrete lines, and one long one down center. One thing I was super impressed with is it rained two day after it went down. Could not find ONE single standing puddle of water anywhere. Is perfectly flat with proper slope for drainage. Vert happy with the job my friend and his crew did.
 

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Fiber mesh dose nothing but control surface cracks, its dosnt replace the need of bar in a pad that thin. Should have had gravel and use of a campactor. The fact it has settled shows the grade was where the problem is.

This.. I work in the concrete business, one of the most misleading selling points companies use to promote fibermesh is "alternative to reinforcement" when in all actuality, thats not the case. It's great for preventing plastic shrinkage cracks. But does very little for overall strength increases..

If your having settling issues, id go after the contractor for failure in compaction/reinforcement
 

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I never cease to be amazed at how contractors can continue to disregard or are ignorant of normal best practices with regard to concrete. I'm fortunate enough to work in the big leagues of concrete but I still come across fly-by-night guys that just don't know any better every once in awhile.

Don't let your mom's contractor do anything more than remove the old slab. Hopefully no stalls are built on it or anything. I'll reaffirm that you want to cut out their fill and bring in properly compacted, low PI, structural fill or agg base. I also recommend thickened edges and welded wire fabric (properly chaired, not just pulled up while standing on it).

One other thing to watch for that I don't think has been mentioned before: Make sure that the concrete guys don't water down the mix and run it out like soup. Some residential caliber concrete guys run-in a lot of water so they don't have to drag the mud. Adding water weakens the concrete.
 
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