Leveling a basement ceiling
I am finishing off one part of our basement, I'll be drywalling the walls and ceiling. While I'm not sure how far it is off, I know the joists in the ceiling are not level and I have a couple of questions:
1. If the joists are off just a little, is leveling necessary? If this is the case, how much is 'little'? Again, I'm not sure but I'd guess there's a half inch or so off in places.
2. Assuming I need to level it, what is the best technique? I'll probably rent a rotary level to assist me but once I find where things are off, do I sister a block of wood on the joist or build up the lower joist directly?
Any tips are appreciated!