Resilient channel
 

Hello I'm re doing my bathroom and I'm thinking of using resilient channel to take out some of the waviness of the rafters. I'm installing a pot light and new fan so I need to know what the thinness of the channel is so I know where to set the boxes. The rafters are on 16 in centers. Thanks for the help

Half inch

Thank you

Just beware that rc channel isn't going to fix any unevenness other than something really minor. Anything serious should be taken care of with a level and line and scabs or shims.

Well as far as I can tell the most severe spots are no more the a quarter inch do u think that is too much?

That will be fine. Anytime we use channel on a ceiling we use 5/8" drywall. In my opinion 1/2 drywall will show the sag and as you push with your trowel to tape it it will move with it creating a hollow seam that will show in any light after you paint. 5/8 is a lot stiffer and will have better results.

Okay thanks alot your help is appreciated