Outlet boxes/extensions for triple drywall
I'm finishing up the electrical in my room before the sheetrock goes back up. After discussing the soundproofing with Ted White, I'll be using three layers of 5/8" drywall with two layers of GG, decoupled with clips/channels.
I've found different adjustable gang boxes and box extenders, but it seems that they only extend up to around 1.75". With the clips/channels plus the drywall, I anticipate that it would need to be around 2.75" out from the studs. Has anyone dealt with this...what options are there for this application?
Thanks for the help.