Shortly after we purchased our current home we discovered one of the piers in the center of the house had sunk so low there as an air gap between the top and the joist. Note, this was missed by the inspector.
Long story short, we ended up using...
http://brackettfoundation.com/It's been over a decade ago. I can't remember how we picked them. They removed the existing pier, drove into the ground an engineered metal column until it reached stable earth, then a new block pier was built on that. Lastly they jacked up the house and using metal shims leveled the house. It has been fine since then. I was very happy with the work.
Richard
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Richard Casto
1972 Porsche 914
2013 Honda Fit Sport
2015 Honda Fit EX
http://motorsport.zyyz.comMoney can't buy happiness, but somehow it's more comfortable to cry in a Porsche than a Kia.