Does anyone have any experience in jacking buildings? My house is about 100 years old and has an attached barn. The front of the barn is on a rock foundation the sides and back are on stilts. the barn is sagging slightly I would like to level it and put a foundation under it. Any advice would be greatly appreciated.
That's just not a typical DIY project. Large scale projects like this where the integrity of a structure can be compromised should be handled by professionals. Bring in the guys with degrees and liability insurance and you will be far the better for it.
Pick up the book "Renovating Barns, Sheds, and Outbuildings" by Nick Engler. It is an awesome book to read if you like barns and fixing them up. He describes and diagrams various options for jacking walls up to repair/replace the foundation.