3 Car Garage Apartment Conversion

I brought this over from the Design Forum for a little advice, so let me preface this by saying "Thank You" to anyone who takes the time to give me their opinion or advice on my project. I am converting a space above my 3 car garage (24'x30') and am looking for some direction on a few issues. I've included a picture of the existing structure that shows the floor plan and 3 different perspective views as well as a floor plan of my proposed modifications. Also, I'm including a blank template with the interior walls removed and the exterior walls placed as far out as the contractor is allowing. This will give someone the opportunity to draw an interior configuration that might be suitable for my application. I'd like to have a control room, a vocal booth, a small live room that could house a drum kit, and a small half bath with a toilet and a sink. I'd also like to utilize a sound lock as an entrance. I have recently downloaded Google's "SketchUp" and am working on a 3d model of the existing structure which should be completed by the weekend. Here is a couple of tidbits of information followed by questions: 1. The 2nd level flooring on this 24'x30' structure is comprised of 16" wood trusses at 24" O.C. with a 1 1/8" plywood subfloor. Assuming that the existing structure will support the additional weight, what would be my best course of action to obtain optimal STC inside the studio? 2. The existing 2nd level interior ceiling height is 8' 1" at it's tallest point and 4' at it's lowest point. The roof pitch is 10-12 (East/West side) and 14-12 (North/South side). Will this be tall enough to create an effective listening enviornment? 3. The design I have proposed will allow for a flat ceiling in the control room, but the instrument room and vocal booth will both have sloping ceilings. How should I treat the pitched part of the ceiling? I haven't compiled a budget for the completion of this project but I do have a bid for the modification to the structure's exterior. I'm not looking to cut corners, but I do want to avoid unnecessary costs. Again, thank you to anyone who offers up their two cents; I need all the help I can get!

dj4- There are several of us with rooms above the garage. An elevated wood deck (your floor) will resonate and vibrate and pass sound. Unfortunately it is had to get isolation there without adding a huge amount of weight that you stucture may not be able to support. You can put in a concrete floor or a sand filled floor, both are extremely heavy. Using the traditional "room inside a room" will add a lot of weight. Here are the links to the others I know about. I hope we can get some advice to find a solution, even though we will probably never have "great" isolation... http://www.johnlsayers.com/phpBB2/viewtopic.php?t=8426 http://www.johnlsayers.com/phpBB2/viewtopic.php?t=9178 http://www.johnlsayers.com/phpBB2/viewt ... highlight= http://www.johnlsayers.com/phpBB2/viewt ... ght=#60097 http://www.johnlsayers.com/phpBB2/viewt ... highlight=

if the only thing below you is the garage,you might not have to worry too much about the sound leaking below - but - you should test to see how much sound leaks down and then out through the garage. a quick check is to place a large speaker face down and pump some loud bass and drums through it and measure both the upstairs, downstairs, and outside. you might have to beef up the garage ceiling as a means improving isolation. i suspect the windows and roof will be the harder bits to isolate.