Garage Rebuild

This is my first post, having spent many hours reading through the excellent resources on this forum, and ploughing through Rod's book numerous times! I hope the following is clear enough to elicit the help I need - I'll learn how to be more intelligible as we go along (hopefully!) Cutting to the chase.... I'm planning to have my current shabby single garage (c. 10' x 15' internally) completely demolished and rebuilt as a single-room studio, and would very much appreciate help with design and logistical issues. I'll try and keep this initial post to the point, and then elaborate as required... THE STORY: We are having an architect-designed small extension added to the ground floor of the house, and the garage is 15' away from the house at the end of the small garden. The architect will be providing the builders with detailed designs based on what I come up with here. The builders are good, and have constructed home cinemas for clients before that have exceeded expectations, and are happy to be nannied about ensuring there are no shortcuts and acoustic-construction specifics are followed. We get little road traffic being a residential side-street, and some aircraft noise. THE GARAGE: Currently flimsy concrete block and slab, with tiled roof. Some of the current wall is brick. There are not foundations or quality build there currently to make it worth developing the existing structure, hence a complete rebuild. As can be seen from the attached jpeg, one of the garage walls is attached to a neighbouring property - this is a serious logistical issue, and I'd like some opinion on whether I'll be able to isolate well enough to avoid ANY sound/LF vibrations getting through to their property...... THE USE: The studio will be mainly a mix-room, my genres being jazz and classical. I'd hope to be able to do single-instrument/vocal/voice-over tracking in the room also. A cable duct to the house will enable me to record there also on rare occasions (a whole other story!). THE BUILD: I have attached a first-attempt at using Google Sketchup - better drawings to come as I get to grips with it! The shape is the current dimension, but will be rebuilt so it is symmetrical about it's length. I'm hoping to pass on specific construction details to the architect, who will then produce proper designs I can post here for further comment. i) The outer walls to be constructed from 110 mm dense concrete block, or nearest equivalent to support the structure adequately. These walls will support the entire outer roof structure (the inner roof to be supported on the timber inner wall frame). The design is a "room within a room" to decouple entirely the inner room from the outer structure. Thus: ii) The concrete slab (rebar reinforced?) will be isolated from the outer walls, by an air gap/trench, with deeper footings around the edge of the slab to provide extra strength for supporting the inner wall frame. This gap will be filled with foam/mineral wool (to be specified) and caulked over if required to provide vapour barrier. ie The slab will at no point connect to the concrete walls or the new foundations for the walls. Slab to be acid-stained and sealed. iii) The outer wall that connects with the neighbour's party wall could be built flush to it (if permitted), or with a gap to be sealed to prevent debris buildup. The neighbour's foundations may have footings that extend under the garage - we wouldn't know until our foundations were excavated. If this would produce unavoidable flanking issues, the project will be scrapped! iv) The wall bordering the pavement to be constructed of the same brick as the garden wall, for cosmetic purposes, and will be cemented directly onto the concrete block wall. (Is this a problem? - I thought it may provide extra mass without creating a third leaf) v) Inner walls to be "inside-out" ie 2 layers of plasterboard (with Green Glue between), attached to frame with Resilient Channel, and inner face of walls to be Rockwool covered in breathable fabric. Monitors will be soffit-mounted. Once the room is at this stage, I'll check the acoustics and add slat resonaters etc as required vi) I borrowed the following roof design from Wurlitzer's similar garage design: ROOF (top down): will be pitched in the middle Three layer felt system, c. 10mm total. (Top two layers bitumen and mineral based torched on. Bottom layer lighter for airation). 18mm OSB 2mm 5kg/m2 MLV 18mm MDF 12mm MDF 150mm timber beams, spaced 40cm apart with rockwool insulation between. The felt roof is to avoid having tiles/slates which will not give an airtight seal. INNER CEILING: currently working on this! To be supported by the inner wall structure and follow the pitch of the outer roof. DOOR: There will be no windows. The door is from a commercial studio and is very heavy and lead-lined. It will be built into the outer concrete wall, and a porch will be added with an additional glazed exterior door to the garden. I need to research more into how to isolate the new door frame so as not to couple the inner wall to the outer walls at that point. At this stage I feel like I'm going round in circles with my research, and the architect is waiting for my final requirements so he can prepare some final plans, so at this stage any help from this superb forum will be hugely appreciated!!!

Sorry, should this be in the Design rather than Construction forum? How do I sort that out? Serious attack of newbness!

Hai Duck and welcome to this fab forum. You'd prolly take your "design" plans to the "design" forum, indeed. There's you can discuss what your space should look like. Than take the design to this (construction) forum to discuss HOW it's build. Finally check out the "acoustics" forum and tune ye newbuild room.