JackF99

The triangle at the corner has equal sides along the exterior and the long side along the inside attached to the rest of the foundation.
The long side shows no sign of dropping, meaning there is no drop at all along that side.
On the exterior slab there is no sign of cracking along the foundation.
Does this mean the footing has not settled?
I would be grateful if you could give me a link or explain this settling problem more.
I'm very sure the guy did not use any foam or other concrete at this corner. He put in double pier concrete pads with rebar and steel shims at the corner, but he didn't put measurements on how far away from the corner the other two piers are. They seem about under where the crack is on the long side of this triangle.
If I get this corner done again, would it be better to go with someone who would use the foam?

nealtw

I doubt your building inspectors would allow the pad to be built up like that. On hills you can get lots of soil changes at a givin depth and likely that corner was placed on poorer soil which should have been removed and backfilled with compacted gravel or just a deeper foundation. I suspect the guy that did your work last time dug down to the better soil and knew what he was looking for. It's just to bad he didn't do more at that time. My fear now is that part of the floor my have to be removed in order to lift the house back up level.
Some times when soil is questionable the city will call for a geo-engineers report on the soil conditions and if that is the case you may be able to put a claim against the engineers insurence, evan fifteen or twenty years later. There is no question that a mistake was made.

JackF99

"If what he did worked at the time, the rest of the footing should have underpinned to actually solve the problem.
Under pinning would have been to dig under the footing and put larger chunks of poured concrete to spread the load over a larger area and fill the voids and the floor should have been lifted with a foam fill at the same time."

So if the guy didn't dig farther under and didn't use additional concrete and/or foam he didn't really "underpin", is that right?
If someone else comes and says he will underpin, can I assume he is going to do something more than just piers on this corner?

JackF99

Thanks Neal,
I would just like to make sure you understand...
This triangle is just sloping from the rest of the concrete, and has not actually dropped any at the attachment of the rest of the slab.
It sloped 1 inch before he worked on it, but now without watering, it is sloping 6/8 inch or so.
It seems very hard that I would have to replace a piece of the floor.
If the whole triangle part just dropped down even at the slab attachment, then yes, I could see that, but it hasn't.
Seems it could be just swung up from the corner with some more jacking and the like you said with some foam and concrete for additional support.

Question:
If I water now and it lifts up a little , the foundation guys won't be able to see the full extent of the slope.
Should I water and see how much it comes up.
Before the guy worked on it, I watered and it rose at least 1/2 inch.

nealtw

The fact that you can change it with water indicates poor soil under that corner. "IF" it will jack back up and go to where it belongs, great. Then I would do underpinning in chunks along the rest of the area to keep it there. I would dig a hole along side the foundation and footing about 10" below the footing and have a geo-engineer check the soil condition. He will be able to tell you how big the footing should be and advise you on how to proceed.

BridgeMan

Why not do it right, and have a foundation specialist install multiple helical piers, lifting the sagging corner and holding it there?

nealtw

Bridgeman may be right, I would consult with local experts so you can decide on the most cost effective way to do this.