Attached Garage Conversion Studio

I started with a specific question in the Construction forum, and thankfully Stuart mentioned there were several red-flags in my design, so here I am, back to the drawing board! The house that the garage is attached to are the offices for the record label that I work for, which is part of a larger ministry that I'm a part of. There is some bureaucracy that I have to contend with, and if this thing is actually going to get built, we're going for speed and cost, rather than perfection. I realize that by asking here, everyone will say, "Take your time; design it right," but I honestly have a small window of opportunity or this will never happen. No, seriously, it won't. I've been told to keep the budget below $30k, knowing that there will be overages. We're meeting with an architect (who knows nothing about studio design) on Tuesday Sept 9 to draw up plans for bids for contractors. On my end, there is a maintenance & construction guy who also works for the ministry that has experience building anechoic chambers for Nextel and Motorola, so thankfully I have an advocate that can explain construction things, and he's on board with everything I need and have communicated, much of which is through "Home Recording Studio: Build it Like the Pros" (Hi Rod!) and this website. At least one of the contractors that is bidding has recording studio and performance hall experience, and I'll make it very loud and clear that recording studio experience is a must for this project when it comes time to review the bids. Isolation requirements are for basic traffic noise from the road (50' away) and driveway (20' away), and other environmental factors (rain, thunder, etc.). The only part of the offices that actually touch the studio are the conference room to the North on the East side of the garage. They understand they'll get what they pay for, so I'm more worried about keeping it quiet for the recording than keeping it very quiet for them. We'll be recording rock music, essentially. Drums, bass, electric guitars, etc. My goal is to have one live room for drums, bass, electric players to stand (guitar cabs can go in the basement) and a vocal booth so we can track scratch vocals without the vocalist in the CR. For the control room, I'd like to at least have space enough for a couch in the back and 2 people to be working up by the computer. There's a lounge & bathroom downstairs in the house, so we don't really need "hangout" space. We have an old studio that got overrun with mold (the building itself was never properly built to begin with... drainage problems, exit-plumbing froze in the winter... nevermind as a studio), but we're salvaging some things from it, like a 75"x27" double-glass window (there are two that are side-by-side actually, but I can't figure out how to use both in a room this size), and a single piece of glass that's 24"x36" that we'll match with another of differing thickness to make a proper studio window, again, from the specs in Rod's book. There's also a sliding glass door from the other studio that I'd like to re-use, possibly between the iso booth and tracking space for good sight-lines. So here is my layout so far, the one that Stuart said had many red flags. Orientation is top = north. The garage doors are to the south and will be blocked in, and an exterior door built in one of the former openings (it'll actually swing in instead of out like the picture). The chunks to the north are a staircase leading to an attic and a masonry chimney. The plan is to demo the interior sheetrock of the current garage and add layers of sheetrock between the studs on the wood exterior of the house. Vapor barrier and existing wood thickness information coming soon. The garage floor is a single slab of concrete. The roof is non-trussed, so at the peak there's 28' from floor to joists, but the garage end has a hip, so that slopes down to the south. I was planning on a 2' gap between roof joists and middle-leaf for ventilation purposes, since the middle leaf would attach to the walls below the vents in the eaves (proper term escaping me). Interior leaf would also have 2 layers of sheetrock, with green glue inbetween. We're planning on building a vaulted ceiling attached to the exterior garage walls to form our upper (middle technically) leaf, and then supporting the interior ceilings on top of the interior walls. The tracking room (Right) will be vaulted, but following the hip angle as well, and the control room will be raked front-to-back at a 12° pitch. I'd like inside-out wall design for the tracking room at least, and add V-Shaped slat resonators along the East wall, since I've got that giant window taking up most of the West wall of the tracking room. HVAC handler and compressor will be on a new roofed-slab outside to the West, and trunks will enter through the gap to the left of the control room, before going up and over to their respective places, in between my 2 inner leaves. I've asked for oversized trunks, calculated the heat load for each room, and asked to keep the velocity down. Also in the void there to the left of the control room will be a silencer for both send and return lines. Here are some more pictures. So here are the questions: 1) What are the red flags? Is there a better layout that would accomplish my goals? 2) Since the roof is the outer leaf, making the ceiling a 3-leaf system, how much of a weak link does that create and how should I plan my other systems as to not waste money and resources? Thank you for all your help!

Environmental Update: I went by this morning with my SPL meter (Radioshack) and measured the noise from trucks and buses going by. The max SPL I got (C-weighted, slow response) was 86db from a street sweeper and a garbage truck going by. The rumble seemed to be in the 70-100Hz region.

Well this project came to a quick halt. To do any interior structure changes, the rest of the building (a house used as offices) would need to be up to code, which would probably cost $50k, so that knocks that option out the window. Back to the drawing board... and my makeshift studio for another year :D

Bummer! It was looking like an interesting project, too. No chance of salvaging it? - Stuart -