Walls and Ceilings - drywall and shim question

About to start a project on an addition to our home. The addition's ceiling is a set of joists that butts up to the roof, but is unfinished on the room side. I plan to put in recessed lighting, insulation and 5/8" drywall. My question is this: There are other pieces of lumber, set perpendicular to the joists, every 4 feet or so in a pattern. Not a big deal, but these perpendicular pieces are slightly 'taller' then the joists; that is, they stick out into the room side anywhere from 1/32' to 1/8". Some are flush though. If I use drywall shims, I'll need to shim every area on every joist where I will be placing a screw.

Would the sheetrock compensate for this difference, or are the shims a necessity? Is there any other solution? Thanks in advance.

You will have to shim or fur down every joist. Maybe you can bang those up flush with a hammer??

If your measuremnets are accurate, 1/32 is meaningless. Even 1/8 inch isnt really a big deal but I would address at least the ones that are bigger.

If you cant bang them up with a hammer, you can also try a plane or a chisel (or even a sander or grinder but that will create unneccessary dust). Even 1/8 isnt very much to remove with either of those.

Before working on these pieces though, check that your joists are inline (lay a long straightedge across as many as you can at a time). If they are out of wack, you may want to shim or fur out the joists anyway.

But, if your lucky, and you can work in just the cross pieces you should be able to breeze through them.

will do thanks. I didn't think I could just throw the rock up there...

It would probably be easier to plane down the small cross pieces rather than shimming all the joists, especially since the heights are variable.

Thanks all.