Building Drum Teaching and Practice Studio

I'm a drummer and teacher who's gotten permission from the relevant authorities (my wife and Mother-in-Law who owns the building) to convert half of our two car garage into a practice and teaching studio. I've been scouring the internet and the library to gather what information I can. Happily, I was pointed to this forum which has provided more information in one place than I found anywhere else. Kudos. The structure is two-layers of bog standard brick (approx. 4" thick) sitting on it's own concrete slab with timber ceiling joists at a height of 8'. The roof is angled up to about twice that height, insulated thinly on the underside and with tile on top. There is currently an 8' high wall cutting the garage in two, just off centre. The wall is made of timber at 2' centres and a layer of chipboard on one side. It was originally built to split a welding workshop off from the other side of the garage. It is connected to the ceiling joists and ceiling beams at either end which then sit on the top of the brick walls. It is easily (re)moved, and with the wall in place I'm essentially working with a gross space of 12' by 9.5' or 12.5' by 7.5, leaving current storage units in place (they have to stay where they are...) As I said, the ceiling joists are at 8'. There is the added problem that there are brick columns of double the thickness of the wall set at the centre of each brick wall, which - depending on what construction technique I use may shorten up my usable space by 4 inches on the narrower dimension. :cry: There are two roll-up style steel doors which my MiL does not want closed up permanently as she intends to sell the house a few years down the line. I realise these are going to be a potential source of significant sound loss, but that's the lay of the land. I'm investigating possible solutions including simply building a double wall just inside the roll-up door, caulking the door shut and using it as part of a leaf, etc. My nearest neighbour's garage is approximately 4 feet away from our garage and his double garage/office is attached to his house proper. It is on a seperate slab from ours and there is earth in between. There is a fair amount of ambient noise in the neighbourhood both from a busy road just behind the garage and a large motorway less than a mile away. We also have an industrial estate across the road the garage backs onto. Unfortunately, a friend's sound meter ran out of juice before we could get a reading of the ambient noise in the evening time (when I'm most likely to be teaching) and he's yet to return with a charged one. However, I'm willing to say that there is probably at least 60-70dB of background noise at any given time. I will get firm readings on this forthwith. I'm looking to get the volume of drums down to a level that me and my neighbour can live with - which I understand is highly subjective. But if I said I was aiming for an optimum STC of around 60 or higher, I think that would do the trick. A little less might be okay, too, but as you know, it's hard to tell. So, I understand that room-within-a-room is the surest way to avoid transmission into the existing structure and I'm considering plans for such a construction using both staggered stud walls and a double stud wall with airspace as recommended on this site over and over. My most pressing questions are these: I wonder if this is actually going to create the dreaded 3 Leaf design with the brick wall, the roll-up doors and the chip board wall providing the third leaf on three sides? Should I consider using the brick as one leaf in a 2 leaf construction? I note from the charts on this site that brick has a fairly significant mass. Would it need to be rendered or would drywall do the trick? Should I do away with the chipboard wall altogether or will it be useful as another layer of mass even when not mechanically attached to the new inner walls? I.e. if unattached is it likely to act as a third leaf? Also, considering that it is attached to the ceiling joists, am I going to significantly reduce my transmission loss by tieing into the studding (in its current position) as part of my construction? Also, I have a question about the double stud wall construction most often recommended here. I understand that you create two separate stud walls at least an inch apart creating about 8" of (insluated) airspace cavity between two leafs of mass. Now, even though the studding will be on separate plates, when you finally lay a ceiling on top or close the sides of the wall combination, aren't you creating a mechanical connection between the two leafs? How do you go about closing the sides of the wall combination to keep out moisture, etc. without creating this connection. Am I missing something or is it not really a big deal? Also with ceilings - it seems it would be difficult to create such a double wall construction on the ceiling without some kind of mechanical connection - otherwise what's holding the top studding up? I would appreciate ANY suggestions/help anyone can provide. I'm sure I have 1000 more questions, but I think the above is a good start. Forgive me if these questions are answered elsewhere on the site. I read through about 30 pages of recommended posts before deciding to (perhaps vainly) start my own thread. Thanks in advance.

Also with ceilings - it seems it would be difficult to create such a double wall construction on the ceiling without some kind of mechanical connection - otherwise what's holding the top studding up?

If you build a room within a room, your new ceiling joists rest on top of your new inner wall frames. If you choose to go this route, your new inner wall frames will need to be shorter in height than your existing outer wall frames in order to allow the new ceiling joists to drop below your existing ceiling joists. You can also use some sort of isolation mechanism such as ceiling hangers on springs if you want to hang your new inner ceiling leaf from the existing joists http://www.kineticsnoise.com This may be a more practical solution if ceiling height is a concern. However, if you MIL is wanting you to keep the garage doors in tact, then building a room within a room would prove to be a challenge given the lack of mass of the garage doors. Unless you can beef up those doors with more mass (somehow?), your new construction will in essence be a slave to those doors as they would be the week link throughout. There would be no sense in building 3 high mass wall systems and a new ceiling system if you can't match the same performance with the garage doors. Consistency in performance throughout is a big key.

Thanks for the reply. If I were to build a RWAR, I would build a fourth wall inside of the garage door on the side I'm building on as well. She wants them to remain in place, but only one has to function. In fact the one I'm planning to build behind already doesn't open. But of course, you're right, the existing "room" will be weak at the point of the doors, and I would be relying on the RWAR walls alone for most of my isolation. That said, if I double walls with the MSM model described here can really get me over 60 STC points if enough mass is applied, I wonder if that'll be enough to get me over the hump. Again, thanks for the reply.