Small Garden Practice Room

Firstly, hello! This is my first post on this forum and I suspect is the topic where most first timers come for advice, so apologies in advance for more of the same. A little background on me I'm a freelance percussionist in London and have had the luxury of fantastic neighbours allowing me to practice what ever I want in suitable hours of the day. This was in a victorian terrace with half brick walls, so as you can imagine, pretty much the opposite of what is desirable! However, we made the fateful decision to move house 6 months back (substantially built semi-detached, two brick thick party), only to be welcomed by a very noise sensitive neighbour, whom very rarely leaves his house. And by sensitive I mean complaining about an electronic drum kit (especially purchased due to previous complaints) on headphones sitting on an isolated platform. This could not be heard from the room next door with the door shut. Anyways, this means that I obviously can't go around practicing cymbals, snare drum and timpani! (Of which I could understand getting complaints about) Plans for a practice studio In our new house we are lucky enough to have a 30m long garden, and thus this ideal place to build a fairly well isolated practice room. This is something I am looking to build myself, as I'm quite handy and enjoy these sort of projects. I have read the usual literature and have a basic understand of isolation (but little on acoustics). My plans at the moment include building a timber framed structure on a good concrete base. The outer wall consisting of (from outside in) exterior ply | some form of waterproofing membrane | 2 layers drywall | standard wood stud wall filled with rock wool. Then an air gap (size to hopefully be advised by you! Inner wall, stud wall with rock wool, 2 layers of drywall. There will also be the external sloped roof and the inner ceiling resting on the interior stud walls. Would it be ok for the inner "room" to share the concrete slab? I intend the internal dimensions to be around 6m x 4m. How does this all sound? Obviously there is probably a lot I am missing. Budget wise, I intend to do this bit by bit as an when I can afford each part. Please may I thank you in advance for your responses.

Don't rush too far ahead with the details (materials, air-gaps, nr. of layers etc.). Take your time. Draw up a provisional floor plan showing basically what you intend. Then we can better decide if it's worth making separate slabs. In general I'd say if you're pouring from scratch then yes, but first you've got to have a definite plan. The drawing program of choice these days is Google's 'Sketchup' which is a great piece of software and free for the download.

Thanks brihar, I'm famillier with sketchup and will get on to doing a floor plan. It really is as simple (relatively) as one space, no split rooms, no windows. My needs are a nice large room I can practice in without annoying next door whilst he is indoors.