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Discussion Starter · #1 ·
I had a Contractor build an addition onto my home, a bedroom and a finished single car garage.

The concrete slab in the garage has already cracked all the way across, just after 3 weeks. Is this normal or should the Contractor be responsible and repair it?

Sorry if i posted this in the wrong section.
 

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i have the same problem i had a contractor pour the slab for my cabin i told him it was going to be exposed but it looks bad cracks poor finish but it was a cash deal so now what ?
 

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Discussion Starter · #3 ·
i have the same problem i had a contractor pour the slab for my cabin i told him it was going to be exposed but it looks bad cracks poor finish but it was a cash deal so now what ?
I haven't paid the Contractor his final check yet, its a fact Concrete cracks but how soon should it crack? I guess we are both at an impasse.
 

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How big is the crack? With concrete it isn't a question of if it'll crack but when. Of course 3 weeks seems pretty darn quick. Too quick.

Of course I'm no expert, dad does concrete though.
 

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could be they ddnt prepare the ground befor pouringand the ground is settling?

or possibly they let it dry too fas pics would be nice
 
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It happens. It happens so much that it is rare for cracks not to appear. It happens so often that there is actually a procedure for scoring the slab with a saw to engineer the cracks in a specific location so as to control the event.
 

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Discussion Starter · #8 ·
It happens. It happens so much that it is rare for cracks not to appear. It happens so often that there is actually a procedure for scoring the slab with a saw to engineer the cracks in a specific location so as to control the event.
Thats called an expansion joint, and he did not put one in. The crack runs across the slab in an offset pattern.
 

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Discussion Starter · #9 ·
could be they ddnt prepare the ground befor pouringand the ground is settling?

or possibly they let it dry too fas pics would be nice
The slab was done to code and was inspected by the County so I'm pretty sure the prepped the ground right, but who knows?????????
 

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When the concrete is poured it can and will crack a bit if the weather is hot enough to dry it too fast. The foundation should still be strong and not be a problem but just a bit unsightly. This can be a minor problem if you plan to stain the concrete and use it as the floor without any type of cover. There will be hairline cracks in most monolithic concrete foundations.
 

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The slab was done to code and was inspected by the County so I'm pretty sure the prepped the ground right, but who knows?????????
It is not normal for a newly installed slab to crack. Especially after only 3 weeks.

It would be a good idea to ask the county if there are any compaction test requirements, performed by licensed field inspectors, that are required prior to concrete installation.

I suspect that the surface was not properly compacted.
 

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As one posted above said it is not if but when concrete cracks. Cracks are usually formed in just a few hours after pouring. You dont see them right away but as the concrete dries it shrinks. About the only thing you can do when pouring concrete is to try to keep it wet for several days to slow the cure down.
If you cant put a coin in the crack, I would say that it probably falls with in "industry standards". I have seen concrete slabs poured on one day. The next day, you have a huge fork lift carrying pallets of blocks stocking it for the masons to build the walls. It nevers has a chance to cure or get to its compressive strength before putting a load on it.
Other factors include subcontractors who water it down so it becomes easier to spread, not using fiber and wire mesh as a secondary reinforcement, sandy or extremely dry soil sucking up the moisture, and just good ole compaction issues.
 

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Ditto Ditto Ditto

It would be a good idea to ask the county if there are any compaction test requirements performed by licensed field inspectors that are required prior to concrete installation.

I suspect that the surface was not properly compacted.


I agree ...... 3 weeks and you have a noticable crack ..... basically one side of the slab cracked away from the other because of non support from a properly tamped base......
 

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We just had a gunnite pool put in. Gunnite is 8000PSI strength, twice what normal concrete is. It is also 8 to 10 inches thick. Also twice as thick as a slab pour. To have a driveway the same strength you'd have to pour it 16inches thick! It had cracks in it within a week, with one running the entire length of the pool. This is of coarse before the plaster has been applied. You can't have too much steel in a concrete job. It wont stop a crack, but it will limit it to being a hairline crack and it wont widen.
 

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How long after it was poured before you were driving on it? Was rebar and/or fiberglass used?

You only get 2 guarantees with concrete.
1. It will get hard.
2. It will crack.
 

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with my slab i did all the prep work i ran a plate compactor over the fill every 2" it was like pavement when i was done i have a crack about 1/16" wide that runs all the way across. i have seen nicer slabs in a garage. i told my contractor i was going to stain the floor but i think all i can do now is install tile
 

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Hold the final payment until they fix it. I have a 3 car garage poured about 12 years ago attached to the house and not a single crack. While a hairline crack is acceptable every now and then any large cracks after 3 weeks is unacceptable.
 
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