| Thanks for the suggestions.
In answer to Pecos' question, it's not clear if the foundation was level to begin with, but it is evident that at some point a previous owner attempted to address an out-of-level condition by installing a false floor in the kitchen. So it's difficult to get an accurate measurement of floor to ceiling heights.
It's down to about 2" now. The contractor installed all-thread at three locations and is attempting to coax it down. However, as I feared, this appears to be putting unnecessary stress on the joists he's pulling on. |