Replacing Foundation of 80-year old Craftsman
My sister and B-I-L (who don't use the Internet, hence my post) have a beautiful 80-year old craftsman home which they love. Recent repairs in the basement revealed that the home is supported on a footing wall that is no more than 1 to 2 feet below grade, and AT grade in a few places. Parts of the basement floor are concrete slab, but some are bare earth.
Despite all this, the floors in the house are level and there is no undue settling, sagging, etc. anywhere in the house. They have lavished a lot of care on the home, and the interior is beautifully restored.
They would like to replace the entire foundation with something that is up to modern standards, and while they're at it, to deepen the basement to 8 foot ceilings (from the current 6.5 feet). The house is much higher than the sanitary and storm sewer lines on the street, so while digging a deeper basement would require replacing the sewer and drainage lines, no pumps would be required.
Jacking the house up to add basement headroom is out of the question -- the roof line is at the limit allowed in the neighbourhood. The only way to go is "down". As with the rest of the work they've done on the home, they hope to do most of the work themselves.
Has anyone tackled a foundation replacement job like this? If so, how did you do it? Two plans B-I-L has considered are jacking the entire house up, replacing the foundation, then lowering the house onto the new foundation; or replacing the foundation in sections without jacking the house up. Either way, he plans to replace the exterior walls of the basement and interior supporting walls and posts with walls that are stronger than what he's replacing.
Any comments? What did you do? What would you recommend? (I have already recommended building a new home but they're resolute that they want to save the existing one.)