OT: House Foundation Peirs

[4GSR]

There's a section of the toll road that runs along by the Circuit of Americas that will test out your shocks and springs at 80-85 MPH, too You vehicle acts like it's going air born for a moment.

 

[Milland]

There's a section of the toll road that runs along by the Circuit of Americas that will test out your shocks and springs at 80-85 MPH, too You vehicle acts like it's going air born for a moment.

Yeah, I've read that complaint about the access roads too. It's all fun and games until your girlfriend or child hurls...

[Have to remind the kid not to mention the girlfriend to the wife]

 

[motion guru]

Related to the squishy geology in Texas . . .

Back in the late 80’s / early 90’s when their was a US based super collider project near Waxahachie . . . the geology studies indicated all kinds of issues related to squeezing ground / clay that would trap a traditional Tunnel Boeing Machine design. I was a young engineer fresh out of college who worked for the TBM manufacturer and was sitting in a meeting where people were brain storming on how to design a segmented shield machine that wouldn’t get stuck. I remember sketching up an idea that was eventually embraced by the company . . .

Like most of my ideas that actually wind up working, I had thought of it while sitting on the porcelain throne just before the meeting. The idea was eventually awarded a patent. I was totally bummed when congress cancelled the project with the tunnel only partially complete. I remember the patent Atty struggling with the patent illustrations and I had gotten pretty good with AUTOCad so I ended up doing all the illustrations for the patent as well. Clay soils were a big part of my education as a machine designer in my early career!

US5205613A - Tunnel boring machine with continuous forward propulsion
- Google Patents

 

[swatkins]

I was called to install an access system on a gate near Waxahachie a few months ago...

As I was driving to the out of the way location I was driving down asphalt roads that were in pretty rough shape. I then turned onto the road, that the address was on, and found myself driving down a really nice, wide and dead flat concrete street.. . I thought to myself that this would be a perfect drag racing road and wondered who had spent all the money needed to make such a perfect roadway on a dead end street....

Turns out it was part of the abandoned super collider project... Us taxpayers spent all the money needed to place that great roadway on our crappy soil.

 

[Doug W]

Retrofitting a pile system to a existing home is always a bit hokey.

Raising the structure at points only reduces the bearing area everywhere else, where the continuous footing and slab (if you have mono footing and slab) used to bear and carry load no longer does.

Using the weight of the structure to drive the piles can only result in equilibrium at most.

So you cannot say drive the pile to 20 tons and yet the load from the house is only 10 tons, having a factor of safety of 2.
A guarantee of no further sinking.
Real pile drivers for commercial buildings and bridges drive the pile to a value far higher than the load it will see.

Plus the skin friction on a small end bearing pile is the main force resisting movement. And those skin friction values change significantly with water content of the soil and weather.

So if you drove the pile in under high skin friction conditions, and then later the soil is saturated and loses those high values, your foundation continues sinking.
This is common with retrofitted mini or micro piles. Time to have it all done again.

 

[ptsmith]

Sorry for the late reply.

Thanks for all of the responses.

I didn't make it clear enough in the first post that only the porch has sagged. There are no problems with the rest of my foundation. The wall that the porch is attached to is actually slightly high. There are no cracks in my sheet rock. The only cracks are in the brick mortor on the side of the window, as shown in the photo. And where the porch meets the wall. No wider than 1/16", oops I mean 0.1250", wide.

My house is built on a slight grade, high on the left and low on the right. There is a steeper grade from my porch to the property line. The grade is more than it appears in the photos. And some of the dirt has washed away from the side. So it could have been prevented. I should have fixed it but never did.

So, I only need 4 piers on the outside edge of the porch. Steel piers will run me $600 each. Not too bad.

 

[ptsmith]

OK there's been a lot of good info posted.

Another thing I should add is I really don't care about this house. I never planned on staying here. My subdivision is great, but most of the surrounding area...not so much. I got a 5 year ARM when I bought it because of that. Well that was 6 years ago, so who knows how long I'll stay. Anyway I mainly want to get it fixed for resale reasons. So cheaper is better!

So the surface friction on the side of the piers can be enough to keep the piers from sinking? If everything goes right? And if not, it doesn't seem like it would be too expensive of a job to get it shimmed. But maybe it is expensive?

 

[Doug W]

So the surface friction on the side of the piers can be enough to keep the piers from sinking? If everything goes right? And if not, it doesn't seem like it would be too expensive of a job to get it shimmed. But maybe it is expensive?

You show a crack on the exterior wall, then state only the porch is sinking?
The porch is supported by the columns and probably square footings and the rest is probably slab on grade with the brink on top.
So the slab isn't supported by a footing or the columns.

And the columns really have no load, only dead load, assuming you don't get snow loads.

So how much weight do you have at a column to drive down a mini pile?
Not much I expect.

 

[Bill D]

I think you would have to have a heavy truck to reach in with a boom and press down on the piling with several tons of force to seat the piling then load it with the lessser weight of the house. Any jackhammer or pile driving would break stucco and drywall.
Bill D.

 

[ptsmith]

You show a crack on the exterior wall, then state only the porch is sinking?

Well the floors in my house are level and there's no cracks in my drywall, so what else would cause it?

The porch is supported by the columns and probably square footings and the rest is probably slab on grade with the brink on top.
So the slab isn't supported by a footing or the columns.

And the columns really have no load, only dead load, assuming you don't get snow loads.

So how much weight do you have at a column to drive down a mini pile?
Not much I expect.

That's a really good point. I think I'll go ahead and have it done.

 

[Velisendderr]

Why it's happening at huge level? I've seen many threads on this topic here and other forums and everyone needs foundation repair service. What's the problem behind?

 

[Velisendderr]

Sorry for the late reply.

Thanks for all of the responses.

I didn't make it clear enough in the first post that only the porch has sagged. There are no problems with the rest of my foundation. The wall that the porch is attached to is actually slightly high. There are no cracks in my sheet rock. The only cracks are in the brick mortor on the side of the window, as shown in the photo. And where the porch meets the wall. No wider than 1/16", oops I mean 0.1250", wide.

My house is built on a slight grade, high on the left and low on the right. There is a steeper grade from my porch to the property line. The grade is more than it appears in the photos. And some of the dirt has washed away from the side. So it could have been prevented. I should have fixed it but never did.

So, I only need 4 piers on the outside edge of the porch. Steel piers will run me $600 each. Not too bad to hire any foundation repair.

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Hi, is it cleared now? As it's old thread and I hope your issue will be resolved. Actually, I'm also facing same issue for my house in Ottawa, Canada and looking for foundation repair experts but it will be interesting to read your thoughts.

Cheers,

 

[Doug W]

Because on low end residential there was no soils report determining allowable soils values.
And the values provided aren't for wet ,saturated soil.
Not having proper roof/gutter to street drainage and excess landscape watering saturates the soil and significantly lowers the allowable soil pressure....and down she goes.

Doesn't help if the home was built on fill.

 

[Velisendderr]

Because on low end residential there was no soils report determining allowable soils values.
And the values provided aren't for wet ,saturated soil.
Not having proper roof/gutter to street drainage and excess landscape watering saturates the soil and significantly lowers the allowable soil pressure....and down she goes.

Doesn't help if the home was built on fill.

Okay right. My case is different and I'm on it.

 

[jccaclimber]

@irontmp , I don't mean to be rude, but you seem to be dredging up a lot of archived threads to put lengthy replies which seem like they were copied from Google. I'm also not seeing a common theme that's related to machining. Are you a real person, or a spammer trying to gain a posting history?

 

[jccaclimber]

Odd look around the area and make sure the third. I tractor isn’t selling you a solution to a problem that doesn’t matter. Also, does the home warranty go against the seller, or the warranty company? If the latter they may have a definition of their own.

 

[Doug W]

I bought a house 3 months ago. No major issues were spotted in pre-purchase inspection. Last month, asked 3 foundation contractors to give a quote for repairing two hairline foundation cracks. Two contractors said nothing special, but 3rd contractor said my house has severe structure issue, foundation is sinking because he saw a vertical crack on the side brick wall. I thought the last contractor just tried to oversell, he asked me to pay $~40K to level the foundation. Other 2 contractors only charge $1300 to fix the cracks. But it keeps bothering me. I spent $600 to hire a structure engineer to inspect the foundation again. Structure engineer told me that the foundation of garage did sink half inch, but it is acceptable for a 20y old house. Overall, he believes the foundation is OK. But I still feel uneasy. The dilemma is, 3rd contractor told me that, because I have legal warranty, in QC, I can ask the seller to pay the cost. I guess I need a lawyer if I go after the seller. I don't know what I should do. Anyone had similar experience before?

You had an engineer examine it, go with his advise and don't worry about 1/2" in 20 years.

Soil acts like a bed of springs, in fact that is how it is modeled. So you will always get some settlement from a load on the soil. Ideally the settlement is more or less uniform.

As mentioned above, don't make it worse by not having proper drainage and watering plants around the foundation.