i have never done this but worked in a town where this was being done. super-shallow (think 2-3 feet) rubble foundations were typical. some folks put a new basement under their +- 1500 square foot house. it worked wonderfully and doors closed that hadn't closed in years. the cost was about $100,000.

If you have a rubble foundation wall, fugettaboudit! If it's blocks, there are two common approaches depending on how much further down you are going. You can use a "bench" around the existing walls, or underpin a section at a time . You shouldn't be paying anywhere close to $100k.

My neighbor has a twin of our house, circa 1908, and he dug out the crawl space, after bracing the house with huge beams, and now has a (full) 9' finished basement. He did most of the work himself, and he did a great job. He had a structural engineer advise him all through it. It cost him about $25,000 in materials and a bit of labor that he contracted out. Our foundations are stacked stone.
Diane

Wow, stacked stone and rubble... makes me think our foundation may have been redone at some point as it is concrete, perhaps by the process you describe, Worthy.

Interesting point that one can go down as well as lift up. As one end of our basement is walk-out I think it would be logical to lift and retain that. I look at some of the houses being done locally, though, that are underground all around, and see they are having to do extensive drainage work to keep the space dry.

Encouraging that doorways etc may even become more square - I was wondering if windows or walls would be at risk of cracking. Stupid of us to do so much interior work before even considering this, but I don't think we could have coped with that magnitude of project from the outset - although we ended up doing a full gutting, wiring, plumbing, new kitchen, new stairs, we nibbled our way into it and didn't have either the experience or the energy to make a big plan in advance. Oh, the benefits of hindsight!

I guess one would also have to empty the house and move out.

KarinL