New drywall job - ceiling isn't even

Uh oh. I just put a new ceiling drywall in a renovation I am doing for my mother. This is an old house that we removed the drywall from and redid wiring and insulation. I replaced the old warped 2x6 horizontal ceiling support joists that needed replacing thinking that when I put the ceiling drywall up it would be level, but there is one area that is out of level by almost 1/2". Maybe I missed a spot?

The good news is that I haven't taped a floated anything, and I could remove the screws holding the drywall in place if I need to see what's going on. We are planning on doing ceiling crown molding and I'm wondering about the best way to fix this.

 

I think you need to remove the drywall to find and resolve the cause.

 

Hopefully the 1/2" is a dip in the ceiling and not a bump out.
The dip, or void, can be fixed with drywall shims. If it's a bump out, the joist will have to be shaved off with an electric planer or other tool.

 

At least you noticed it before taping and mudding. Now is the time to fix it even if it means taking down the sheetrock. An hour spent now could save you hours of hoakey tricks trying to conceal it later.

 

Another vote for removing the drywall and fixing it now. Crown molding isn't the easiest molding to install and having a ceiling with dips or humps makes it even harder.

 

Thanks guys. I think I'm going to take some ceiling down temporarily so I can put some drywall shims on. are these special type of shims that I can buy at Home Depot or Lowe's? Or are they just standard tapered door/window shims?

 

Drywall shims are 48" long by 1-1/2" thin strips. I want to say cardboard, but they are much better than cardboard, non-corrugated, and stable. You can buy them at home centers in a bundle.

They are perfect if you need to fill a dip in ceiling, just staple shims to underside of joists to make a flat plane, then reattach drywall. If a bump, post back. Bump is harder to fix.

 

Thanks Handyone for the great suggestion on picking up some drywall shims. One minor problem... I went to Home Depot and asked a Home Depot guy where in the store I could get some drywall shims and he said Home Depot doesn't have them. In fact, he said he has never even heard of a thing called drywall shims. He did say that the have shims for doors and windows, but that there wasn't anything that Home Depot carried that was called drywall shims. He even asked two co-workers and they said the same thing.

Is there another name for these mystical drywall shims. And if they are a true 48" x 1 1/2" would I be able to find them in lumber and they are called something other than drywall shims? Are these things tapered like door/window shims? How thick are these drywall shims?

 

Around here (probably Texas too) there is no place that handles those (IN STOCK) aside from your major commercial drywall warehouses. You can order them from HD or Menards for $15 a case but for the average homeowner, who is going to do that, and what will you do with the other 99.

Personally I would either cut a shim as needed (on a table saw) or maybe install some solid blocking between joists or perpendicular to joists so that you have nailing area for the top edge of the crown moulding.

 

I've never seen any commercially made drywall shims but like X will cut them on a table saw as needed.

 

That's odd the store wouldn't have them. They come in pretty handy.
They are flat, not tapered and are just simple strips of non-corrugated fiberboard.
You could cut strips of 1/8" luan (door skin) if that's not too thick.