How flat should framing be before drywall?
I should start this by sharing that I’m an owner-builder with no professional building experience, so I hope you’ll bear with me here.
After our roof trusses were installed, I noticed that some of the bottom chords were slightly out of plane. I fastened strapping below them with countersunk screws, backing some of them off a bit to make them roughly co-planar. After that, I checked everything again every 2′ with a 4′ level starting where each sheet of drywall would. I found 3 places where the strapping is proud by at most a little less than 1/8″ in that span. These places all fall inside a single sheet of drywall — not at the long edges.
I’d really prefer not to have to shim every other piece of strapping if I don’t have to, so my question is is this ceiling acceptably flat for installing drywall or could this level of deviation result in drywall cracking or other issues?
Replies
1/8 of an inch is pretty much the standard.
You might notice it in very shallow lighting conditions, but only if you look at it.
(flat paint is your friend.)
Next trip to your local supply place, go to the stack of drywall and pick up an end. Within reason, it is pretty flexible, and as long as you understand that nails or screws are meant to hold drywall where you first hold it, you should be ok. (not get it close and have the screw pull the drywall into place.)
Ceilings are much more critical than walls. Walls are broken up by doors, windows, furniture and hangings, and mostly lit unevenly. Ceilings are large flat planes that can show the slightest imperfections,
Google butt board drywall backer.
It's used for the short ends of the drywall that doesn't have a bevel. In effect, the butt board gives you a bevel for the short end and makes a much smoother ceiling.