Corner of Foundation

[JackF99]

If this is not the place to ask detailed info on foundations, please direct me to another forum where I could ask such questions.
Anyway...
I have a 1300 sq ft house with a bedroom that is approx. 14x11.
The problem is that a 9 x 9 foot triangle of the corner is dropping down about 6 eights of an inch. The triangle is 9x9 and 14 at the base. Hope you can visualize that. The 14 foot base is leading further into the foundation.
I've had a guy come out to put piers in, but this corner is till down after about 3-4 years. Is there some reason not to put a pier right at the apex of the corner?
I have a crack in the dry wall seam and when I place my 9 foot level down it is about 6/8 inch down. I know some will say just water and it will rebound but I would like some sort of better insurance it will not drop again.
This is in Texas and I had the guy come out and the rest of the house is good.
Just this corner is the problem.
There is a 30 inch drop from the corner to the bottom of the next house level.
I know this is probably the problem cause everything wants to go down hill.
Any opinions are good.
Just want to get some opinions before I get some more bids on further work.

 

[nealtw]

Some photos would be helpfull

 

[JackF99]

The bedroom is at the far left corner of the house and here is the 30" drop down to the next house.

The level is 4 feet. The crack looks far worse than it was since I used a chisel to widen it in preparation of patching it with mapei.

Another shot..

The wall has a drywall joint rip from the window to the corner of about 1/8 inch or so.

 

[nealtw]

It looks to me like a slab on grade house, so I am confussed about where you installed a peir?
Is there any damage to the outside of the house, cracks in the brickwork, crack in foundation?

 

[JackF99]

Well, the guy dug out a rectangle shape under the slab edge and then used a auger to drill down two holes about 14" or so in diameter.
He then put rebar in and filled with concrete. A few days later he added steel spacers and jacked the house up.
This is what people call piers here I guess.

 

[JackF99]

Before he worked on the house there was a crack down from the bottom of the window through bricks and mortar and one horizontal mortar joint had a 3/8 inch space for about 8 feet.
This happened a couple years ago in the second hottest driest summer we have had in Dallas.
I'd also like opinions on... can a pier system hold up a corner like this even if the soil directly under the corner is dried out.
I'm thinking on renting this and I know renters will be too busy to water this corner as they should, no matter what they say.

 

[JackF99]

Not sure why the time is 5:19 on this post. My clock is ok and I'm on CDT and it is 11:23

 

[JackF99]

Another thing is that at the roof top the fascia boards had separated about 1 1/2 inch. The brick now looks good, no cracks, but the
caulking between the bricks and wood on the side had torn about 1/4 inch gap.
I want to put flooring down but want this problem fixed with some certainty. Only putting vinyl planks now but later may need something level straight and smooth for laminate whatever.

 

[nealtw]

So if the house was built like we build them it goes something like this.
Dig down to solid soil that can support the house and pour a footing, something like 18" wide and 8" deep, on top of that pour a foundation to height and backfill that with compacted sand and pour the floor level with the foundation.
You said this problem was about 9ft in each direction from the corner, my guess is that the foundation is broke in two places and tilted down to the corner. If your guy lifted the corner up he lifted that hole area off the ground including the floor.
So if each crack is 9 ft away from the corner he lifted 16ft of footing which is 192"x 18" =3456 sq inches all being supported in three places, maybe 1/4 of the weight is resting on the dirt right at the crack on each side. One half of the weight is resting on the pier, so he repalced 1700 sq inches of footing with 300 sq. inches of peir.
If the floor was also lifted at that time, it was also lifted off the fill and that weight was added to the problem.

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.

My fear is that the footing has settled at the cracks, if not you may be able to jack it up again and underpin the footings, if the footings have settled at the cracks, you have a much bigger problem.

I hope this helps you to understand what is going on and I think you should find at least 4 foundation pros in your area. If they all have different solutions, get an engineer to design the fix. This is not usually diy freindly.

 

[JackF99]

Thanks Neal for offering your help.
What I understand about the way people build neighborhoods like mine is...
Plan out the streets. Dig down for the sewers and streets to make them good and throw all the loose fluffy soil up on the sides to build the pads where the houses will rest. I made a mistake buying the house foundation wise as I can see now that I'm close to the end of a cross street, I'm 2 houses away. The intersection is the low point and after that the street goes up again. There are probably 14 houses where the grade goes down parallel with the street and houses.
I can't imagine that all these 2 story expensive houses herei Plano on a 15 foot grade to the street don't have some foundation problems.

 

[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]

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

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