Assembly questions-details

Hello- I began this thread in the Design forum and realized it should probable be here in Construction. Apologies to Soundman for the confusion/redundancy. Like many around here, I've read the forum and Rod's book, lurked, and dreamt here for a long time, but I am finally ready to build my basement recording studio in Northern California. I am hoping that the attached detailed drawings can help clarify my design. Here's the situation: The existing conditions: a primarily sub-grade garage space contained by 8" thick concrete walls, a 5" concrete slab on grade, all 10 year old good quality construction. It sits directly below living space. The project: Build a reasonably balanced/reasonably isolated personal recording/limited-use rehearsal space for a pop-rock band (not super loud) within a family home. Most of the use will be limited to guitar amps and vocals, but there will be occasional drums. I don't need perfect isolation - just enough isolation to avoid being very disruptive to the spaces above or my neighbors (urban living - 2" air space from house to house). I have attached the plan and the 2 wall sections that exist within the space. Here are my questions: Generally: 1. Does my plan have any major issues? 2. Do my wall/floor/ceiling assemblies have any major issues in terms of decoupling/flanking? More specifically: 3. These wall sections assume I will tear down the GWB ceiling currently screwed off to the joists, and replace them with the rock below subfloor and 2 layers on RC. I understand a bit about the issues of a triple leaf assembly, but was wondering if there is any other approach that avoids tearing down the existing GWB ceiling? I have very limited ceiling height (7'-7") 4. Do I need to fill both stud walls in the double wall side of the room with batts or just one side? Thanks again for everyone's help and advice. JP

Hi folks, I'm hoping I've provided enough detailed info for a bit of input on my questions. If not, I'd be happy to fill in the gaps. Soundman, I really appreciated your input on my other post. Any thoughts on these questions? Anyone? Thanks in advance! JP

Your print reads that you have >rigid insulation< in the overhead joist cavity. Lose it, you already have fluffy insulation, the rigid isn't going to do anything that justifies the cost. "I understand a bit about the issues of a triple leaf assembly, but was wondering if there is any other approach that avoids tearing down the existing GWB ceiling?" No sir. If you choose to not remove the existing ceiling then you could install additional layers of sheetrock to the existing sheetrock. But in an attempt to do a full room-in-a-room, you will have to remove the sheetrock to develop the mass/spring/mass required for good isolation. The problem with basement ceilings is that often when you remove the existing sheathing you will find all manner of wiring, plumbing, ducting and gas lines that impede progress and create specific challenges that may not have been considered. Your print also reads that you will install RC-1 on the ceiling, you want to get resilient channel with 2 legs, typically rc-2 is what it will be called. You may also be able to exclude the use of sway braces (code permitting) by installing OSB in a vertical fashion on the interior side of the framing to give it structural rigidity.