House built in 1922 with less than 6 ft ceilings. Dug out 100,000 lbs of material and hauled it off in buckets. Took me about 3 months. Now we have 8ft ceilings. Foundation work handled by professional with proper permits.
** progress pics in the replies.
After World War II a lot of the soldier came back looking for work and many of them dug out the crawl spaces in our area plus added the shelf foundation. This is according to my father in law. I trust him but I haven’t looked into it further to confirm.