Twenty two feet on a side? This can't be too difficult.
Get enough bids on this job so that some of them cluster around some average price, at least five bids.
A Net search came up with half the cases being between $2 to $4 per sq. ft. and one case coming in at $7, including BridgeMan's.
You also might want to find out if it still may sink by having a civil or structural engineering consultant do soil testing.
Last edited by Wuzzat?; 01-23-2013 at 07:10 PM.