I have a 50's era Ranch recently bought for remodel - single story - ~42ftx32ft. Pier and beam with perimeter wall - 5 beams running length of the 42 and 7 piers each beam.
The 1st layer of flooring is the 3.5" T&G installed at diagonal. The second floor is 3/4 plywood or 3/4 oak depending on which room.
The house needs leveling and I have hired this out. While checking on progress, it appears some of the joists and beams have dryrot - possible termite damage from past (no current evidence) and we have replaced and scabbed some of it. The piers are cylindrical concrete and very good shape. The perimeter wall has a few places of cracking and obvious settling but can be shimmed where necessary. I have directed them to open up the floor in several areas for better access and to see what is going on underneath.
After all that, my question is simple. What is a realistic expectation for "level"? How much deviation should I expect or accept? For example - 1/8" across 20 feet? A 6' level at all angles?
I will post some pictures of what we are doing later as well - I know we all love pics.