What is level?
 

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.