How flat should a ceiling be, to be ready for sheetrock? Currently my ceiling joists are a little wavy, with a couple joists 1/4†out on two foot centers. The difference is usually gradual, spanning across several joists. The room is about 22 feet long and the biggest difference overall is about 3/8†in the middle. <!—-> <!—->
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So what is acceptable and what’s not? Should I install cardboard shims and make every joist exactly the same or is that unnecessary? I’ve spent a lot of time on this room so I definitely don’t want my new ceiling looking like the <!—-> <!—-><!—-><!—->Pacific Ocean<!—-><!—->. <!—->
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Please advise.<!—->
Replies
When you look up, once the ceiling is finished, you will not notice the 1/4", ceiling are not like walls that you can look along and see the 'bumps'. Different perspective, I would not worry about it.
what thickness of sheetrock will you be using?
I dont worry until I get into the half inch range. Who ever is taping should take care of any irregularities. Go ahead and rock it.
Two foot centers? Use 5/8 DW and nothing less.
What finish is the ceiling? When you walk into the room is the ceiling reflecting light from windows on the opposing wall?
Usually 3/8 over 22' shouldn't be a problem.
I haven’t ordered the sheetrock yet, I was planning on 1/2 inch but from what the group here is saying it sounds like I should be using 5/8 inch.
The finish on the ceiling will be some version of knockdown. Ceiling has recessed can lighting and windows in the room are only on one wall (southern facing so lots of light).
I guess I'll fix the few joists that are really out of sync with neighboring joists and let the gradual deviation across the room go as is. Seems taking care of any really odd spots will help the tape guy do a better job anyway.
Thanks, John
If your jobber carries the whole line of USG drywall, they make a 1/2 thick rock specifically for ceilings, called "anti sag," which has square edges, not tapered.
Perfect for knockdown, and made for spans of 24 inches.
I am thinking you gotta be in a big market to be able to get it. Where I am, we cannot even get 54-inch rock.