Just removed the old ceramic tile and what looks like old backboard from my 1970's bathroom. I always suspected the floor was not level and sure enough- parts of the subfloor are warped. (not wet)- I'm going to remove the warped pieces and once I do - if the actual joists are uneven- what is the easiest way to fix to insure a level subfloor?

 

It was common practice in the 70's in consumer built homes to set tile right on the sub floor irregardless of the deflection.

So if you have some type of backer board it is probably not original.

The joists Will be uneven and not 100% level, its rough framing.
They used 2' and 4' levels and maybe, maybe a string line. As I said it's rough framing.

"if the actual joists are uneven- what is the easiest way to fix to insure a level subfloor? " Not by addressing the floor joists.


Don't worry about the floor joist's unless they are way out. If they are then there may be bigger structural issues.

Install your new sub, and assuming you are setting new tile use floor leveler.

Now if your joist are 2x10 16" O.C. spanning more then 12' I would look into supporting the bath joist's.

Deflection is always a big issue with hard finished flooring.
Good luck with you project!