Slab inspection questions

[Benno]

What's the typical tolerance for a slab in inches?

I was told 1 inch for new builds..

I'm looking at a home that has 2 inches on either side-2 and +2 almost a slope to make 4 inches.
Surprisingly not much drywall cracking or repairs done.. even outside brick is not cracking.

My next step would be a hydrostatic test but im not sure I'm that crazy about moving forward. Single story home built in mid 90s.

The people I deal with won’t pour a new one if it’s over about a 1/2” difference at any point during a form inspection. They’ll make sure it’s addressed before dropping concrete.

If I’m reading your post correctly, it appears there’s a total of a 4” difference from one point to another on the extremes. That is definitely excessive, and I’d be taking a pass unless further analysis was done and a long term warranted fix was provided.

That’s some pretty high tolerances. Personally never seen anyone put a compulevel on a form. Must be multi million dollar homes. How do they shoot the tolerances on those large foundations in the center as they drag the concrete?

That’s a lot of movement. I’d get repair costs to have the slab leveled before moving forward with the transaction. The interior house could have been repaired since it settled or just not cracked for whatever reason.


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How do you know there’s movement without the original elevation measurements?

I'm an appraiser and would pick up on that just by walking the rooms. No technical testing or anything like that. I'd feel that big of a difference just by walking the floor plan. Instantly.

Not chance in hell.

More investigation needs to be done. People talk about slabs being out of whack but who really knows how true it was to begin with.

One correct the answer

1/360 is official engineering evaluation. 1" over 30ft.

I've seen a slab poured with close to what you are saying, very uncommon, but does happen. Absolutely zero evidence of any movement. I saw it on a relatively new house, two story, in las colinas area. Absolutely no way it moved that much with no evidence. I can find plenty of evidence on just 0.5" movement.

My first thought is that i don't trust the measurements, from lots of experience. Do you have a full elevation map to show? Is it linear across the house or a step function?

A second correct answer.





People have zero idea how out of level their foundations are the day the slab is poured. You go from vinyl to carpet you already have a 3/4 to 1” difference on a compulevel. I have run a compulevel on more finished homes than the average bear, it is not uncommon at all to have. 2.5-3” difference from one side to the other, especiallly when different floor finishes. If you don’t see large cracks in the foundation or major repairs in the drywall chances are the slab has not failed. PM if you want more information, I’ll give you my number and we can talk. Not going to argue with a bunch of construction “experts” on a hunting forum.

[kingranch]

Center zero was in middle of kitchen/house

My biggest concern is resale later down the line. I could live w stabilizing it w a foundation repair however I feel like it would keep me from doing any major improvements or upgrades to the home.

[Wits_End]

Based on information given this house has a foundation issue. Visual indicators with measurements that confirm. Basic inspector cannot tell you this straight because it requires an engineer. He doesn't want to be solely responsible for a sell not happening in an area outside his expertise.
I haven't heard of slab skim coat in context of it being something normal, only ever heard of this as a self leveling correction to bad foundation.

4" across a standard house can easily be felt by someone with experience.

[Txhunter3000]

I don't think they are talking about a slab skim coat, they are talking about the underpinning on the vertical face of the exposed slab to make it pretty