Taking out "camber" on 2x12 ceiling joists

[strutaeng]

Hi guys, I'm working on installing strapping on my addition project. The ceiling joists are 2x12 @ 24" o.c.

My framer installed them with a positive camber (sad face,) as he should. The problem is than they are higher than the adjacent ceilings joists. This was not evident until I started installing my 1x4 strapping for the drywall. Normally around here the drywall gets installed directly on ceiling joists; that's not really relevant to the issue, just an FYI.

Does anybody have any ideas. Maybe just shim the strapping so that it is level? The worst ones are about 1" higher than the rest.

I thought about installing some plywood in the attic and putting something heavy up there to bring down the hoists that are upward, but that's a lot of work, and probably a lot of sandbags, LOL. I suppose I can calculate the load to produce a given deflection, but that does not seem practical?

I know if I kerf the bottom of the joist it may come down, but don't want to reduce the capacity of it. The span is about 22'. It will be just attic, so just random light stuff stored up there.

The real answer is: "You should have used TJIs!"

 

[gungatim]

You can just nail some 2x blocking where there is a gap between the joist and the strapping and attach the strapping to the blocking. that's how I did my basement where I needed to level it out. or shim, whichever is easier.

 

[PCustoms]

Don't kerf, bend or cut anything!

Sister on a 2x4 to match the other joists height where the gap is large. Shim the strapping down where it's minor.

I did this with a laser and story stick to level 1300 sqft of ceiling. Goes fast when you get in the groove

 

[Slowgsr]

Yeah cut up some 2x4s, say 12". Pin it to the side of your truss at the proper height. Then nail up your strapping.

Just don't cut the 2x4s so short that they split on ya.

 

[The Cobbler]

I have done several ceilings/walls in older homes that needed to be "leveled or trued up "
for ceilings I would strap with 1x3 perpendicular to the joists, and shim them as needed to true them up. a series of string lines properly placed parallel with the the joists makes easy work of it

 

[MushCreek]

I had to shim all of the strapping in my house because the trusses were so wavy. It came out perfect, but it was a lot of tedious work.

 

[Indy_500]

I finished my basement a year ago on my 50 year old home and I'll be honest i hung the drywall right on floor joists/ceiling joists and the height of them was all over the place. 1 year later no cracks and you cant tell any waviness in the drywall. I thought about using a hand planer to try and even things out, i didnt have any room to even drop the ceiling down 1 inch or i wouldve had to trim all the doors due to only having 80"ish ceiling (it varied from probably 78-82 due to concrete and floor/ceiling joist inconsistencies)

 

[wrenchguy]

Dry line ur ends using lowest point of total area. Then dryline ur runs and pin shims as needed. Screw ur strapping up thru the shims into joist, then ur ceiling will be on plane.

around here ur term camber is known as crown.

 

[Denwood]

Just shim your 1x4s as required. You can also sister metal studs (cheap) to existing joists. This is how I dealt with same on a theater project.

 

[strutaeng]

Ah, yes crown is the correct term!

I'll have to adjust the strapping I've already installed, but no big deal. I bought a PLS 480 laser that is becoming really useful for all sorts of things so far, I guess I'll need it again!