My parents started an "addition" to our house, that was really more adding the old house onto the bigger new house. The jacked up the old house, spun it 90 degrees and moved it 150 feet onto the new foundation. We forgot something on a small shelf and it didn't move a millimeter.

I did later jack up a couple joists under the old house that were sagging and sister in some new joists. Unbelievable that one can be so used to a bounce in the floor that you don't notice it. Walking across the floor after the new joists were in place was stunningly different in how solid the floor felt.

1.5 story house was jacked up, corner of the foundation jack hammered out then replaced, along with a couple new courses of cinderblocks. The dirt center was dug out, french drain laid in, and a slab was poured to convert the crawlspace into usable storage space. It ended up being more like a half-basement, if there is such an animal.