We have an older house, at least a hundred years old and the living room floor is bowed upwards by about 2" in the middle. A marble seems to stay fairly still when placed around the wall areas, so I guess the corners are fairly level. The floor is a hardwood block floor and has "valleys" between what are obviously joists under the middle part of the floor.
Some of the door frames are at a slope, but being wooden framed there is no apparent cracking anywhere. there is a huge beam that runs along the middle of the floor where the bowing takes place.
It is a two story house, with the main floor area being about 24x 24 (where the problem is.
I am assuming that the corners and outside walls can be 'jacked' up to alieviate the pressure in the middle. (I guess the central beam is grouded on something)
The question is, living in upper michigan I have no ballpark idea of the cost of the operation or any local contractors who (importantly) would be competant.
The ground goes from soil to solid rock in a matter of feet.