Levelling Joists

[rothbard]

I am about to put subfloor in.  I used the crawlspace design with 2x12 20' long joists (select structural).  Curious if anyone here did any levelling techniques on their joists.  I discovered after I already finished framing the floor that the crowning and warps in such long joists can lead to quite significant different from one to the next.  I think since I used SS lumber I can get away with planing them down quite a bit if needed (up to 3/4" or so), but also curious if anyone has just scabbed segments of smaller lumber on the sides to level the tops or shimmed them.

This is my first time working with subflooring.  But I have no interior load bearing walls.  Honestly don't care if it's not level, just curious just how bad I can get away with on uneven levelness of joist tops with 3/4" plywood.

[NathanS]

I would leave it. Glue and ring shank nails to hold down 3/4 subfloor will go a long ways to pulling everything tighter. If you put a wood floor down it will hide difference even more.

If you feel like you have a gap between plywood and joist somewhere, you could draw it together with a screw, then glue will hold it once it's set, I doubt you will need to do that but could have it handy just in case.

My second floor 2x12 joists had a fair bit of variance to them - actual dimensional variability. I can subtly tell where the midspan beam is, but I am sure no one else can notice.