Originally Posted by BIGmouthinDC
frame on top of the shoulder at the very edge, then add isolation clips for a clip and channel attachement of the drywall. You can run the bottom piece of channel with the clips anchored to the shoulder with cement screw fasteners.
After consulting with Jeff, I think we put together a good plan. I've updated the SketchUp to the latest plan:
1) The chimney wall will have 2x4 framing along the edge of the cement, then use clips and channels to isolate drywallx2, except for where the chimney bumps into the room. In this spot, the framing will stay 1" from the chimney, use clips and channels + drywallx2, but the shoulder floor will be isolated by an underlay and then OSB/wood covering, to treat it as if it was more of the floor. Of note, the joists are running across the narrow width of the room and they cannot use the chimney as structural support, so the framing here must be the full height of the room.
2) To mask the bump-out of the chimney and maximize the usable width of the room, I'm currently looking at building a ~9" deep shelf above the chimney shoulder. To be used for game wireless controllers, game systems with wired controllers, popcorn/drinks, decorations, etc.
3) The other 3 walls will be 16" OC framing built 1" away from the cement block walls, isolated by placing underlay under the 2x4 framing, building 1" away from the above joists, then using IB3 clips to attach to the above joists at ends and every 48", then attach 2xdrywall to these walls. Plan to figure out where I'd like in-wall speakers to leave 16" spaces where I plan to place them eventually.
4) The wall separating the mechanicals and the screen/speaker cavity will be a staggered 2x4 stud wall, 6" wide, planning studs each to be 6" separated (12" apart on each side of the wall), then attaching drywall to each side. I think we were planning 2x layers on theater side and 1x layer on mechanical side.
5) Modify screen wall to be AT screen instead of baffle wall, then add acoustic treatments surrounding the behind-screen speakers to resist reflections. This is to simplify design a bit and to help decrease a bass dead spot in the middle of the room where the seating would have been relative to the rigid walls in the front and back (22' wide room, primary seating was exactly 11' center). Now the room should be more like 24' from rigid front/back walls and seating ~13' away from front rigid wall.
6) Debating whether to add strips of 5/8" drywall between the joists of the ceiling attached to the above subfloor to deaden footfalls (as shown here https://www.soundproofingcompany.com...dproof-ceiling
). My contractor gave a price for doing this work and it is significant for us. Debating how much this would decrease footfalls. It will be a hardwood floor above the surface. My previous plan was fiberglass insulation, RSIC-1 clips & channels, 5/8" OSB, green glue, 5/8" drywall.
7) Swapped door to opposite side of mechanical wall because that will be the sound controlled wall. The door-sized opening next to the screen will be potentially filled with a cloth-covered frame to hide the space and have a flat front wall.
8) The AV closet is now only a maximum of 18" deep (without a front enclosing material). I think I'll need to relocate the main AV rack to behind the screen for the receiver, amps, UPS, and things I don't need to access frequently (HTPC, TIVO?). But I'm thinking of still building a small closet for video games and peripherals. Specifically, things like Switch, 4k UHD player, PS4, etc will need to be accessed frequently to insert media, so it'd be nice to not need to go behind the screen every time.
1) I've run the framing plans by my contractor and we're figuring out details.
2) I stopped by tractor supply co and picked up 15 sheets of 4x6' 3/4" horse stall mats, which was the payload capacity of my van. This should be enough to do the outer framing walls and I'll try to get the rest when I can next week. They're pretty heavy, but I think they'd survive falling into the basement space, so I just need to drag them over and drop them in.
1) Is the cost of the drywall strips to decrease footfall noise worth it??
2) Can I figure out everything for the ceiling so contractors can just place correct materials instead of placeholder drywall on ceiling to satisfy inspector? I'm pretty close to figuring out exactly where I'd like everything in the ceiling. I could potentially get wires in the right place for atmos speakers and get a conduit run between AV rack and projector location. Then I could have the contractors place up the real ceiling instead of having to remove the drywall (and reuse it??) just to access in the future.
3) AV rack and projector location? I'm concerned with the AV rack being in the "lobby" because that's a lot of wall to go through (cement block +/- chimney/closets) for video game controllers and I'm worried about signal. My wife hated the idea of everything being in the mechanical room because it'd be annoying to use any physical media. So now I'm trying a split with loud/big stuff in mechanicals area but game/media stuff in small closet inside theater.
4) If the contractors have to put a drywall layer on ceiling to satisfy code (and OSB hidden above that, since I was planning 1x OSB layer then 1x drywall layer), does that mean I ALSO would need to do one of the wall drywall layers to be able to make the tight ceiling-wall seam intersection (ala https://www.soundproofingcompany.com...intersection)?
1) Plan HVAC route
2) Soffit design
3) Lighting plan (tentatively planning sconce lights vs in-soffit lights)
4) How to sound-isolate in-wall surround speakers
5) Make SketchUp of framing plan to show contractors exactly what I want?
Thanks Jeff for the great help and everybody for thoughts or suggestions too!