I have a garage that was built pre-1900. All of the wood siding, studs, and beams are in relatively good shape (no rot). At one point, a car port was added on using all wood construction and this has caused the garage to lean, and some of the walls to slip off the concrete slab. I know I will probably have to remove the carport and make some adjustments there, but how do I go about getting the walls back on the slab and straightened out? The roof is in good shape; it just needs new shingles. Is there a way to try to raise the roof, so to speak, to straighten out the walls and get them back on the slab? I'm sure I would hire someone to do it for me, but how big of a job will this be?