Acceptable Crown for Drywall Installation
I’ll be building my non-loadbearing interior walls out of 2x4s just short of 8′ high and covering them with drywall. When I went through the stack, which had been sitting in the unconditioned indoors of the house here in central Arizona for a few months, more than half of the studs had some crown. The opinions I’ve read elsewhere about how much crown is acceptable before installing drywall range from 1/8″, which seems unrealistic, to “No one will notice if two studs with a 1/4-in. crown are aligned the same way.” I expect most people posting on the other forums I’ve checked or writing articles want to sound as particular as will be credible, because it indicates higher craftsmanship. My craftsmanship is at a bare minimum, at best. I have enough studs with a crown of less than 1/2 inch over 8 feet. Given a slightly crude-looking house overall, what is the maximum crown I can accept in my wall studs if I use straight ones for the top and bottom plates and at the doors, use all similar crowns with the same orientation in a given wall (not mixing crowned and straight), and install the drywall horizontally, which I understand helps?
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What matters is not so much the absolute measurement of the amount of crown, but how it looks visually. If the stud is straight enough that when in the wall it doesn’t appear to obviously bow out, you’ll probably be ok. What you want to avoid is an obvious bulge or depression in the finished drywall.
Hanging the drywall horizontally helps since you span more studs and spread out forces over a larger area. It also helps to use 5/8” drywall which will give a flatter finished wall surface.
I just finished a “down to the studs” renovation of my office at home. I found a few studs that were around 3/4” off in some spots with respect to others. I wasn’t expecting that and didn’t see it until I’d hung drywall and saw the depression when looking down the wall at an angle. I took off the drywall and checked things with a long straight edge (I used a 6 foot aluminum level for this). I shimmed the worst studs with strips of luan cut about 1.5” wide, but intentionally broken on the ends to cause some separation of the plys. The separation of the plys made for a more gradual tapered edge which helped to shim things. I put shims in the worst spots stacked up to get all the studs even when checked with that long level, then I put the drywall back up.
Any small indentations can be filled in with mud by skim coating. It’s easier to fill indentations than it is to conceal bulges, so I’ve found its better to have studs bowing in than bulging out. Obviously this can’t be done if you’re finishing both sides of the wall (I had one side an exterior wall where it didn’t matter).
Bill
You should always crown studs and mark them so the crown faces the same way. On an 8’ stud I like to shoot for 1/4” max but I know the guys are sometimes throwing in up to around 1/2”. You can tell by looking down the siding.
After the wall is up, I take an 8’ level horizontally and check all the walls halfway up, spray paint studs that cause the level to rock and then plane them flat. Bad interior studs I’ll plane or in non load bearing you can cut the stud most of the way through and the drywall will draw it inline with its neighbors.
Thank you, Bill and T.