garage fit-out - floating metal frame?

now that my fella has cleared the 1YO mark and is already showing to be great on the drums and ukelele, time to go back to the plans for partial fit out of the garage. so here's a construction technique query. i'm not overly concerned with dimensions at this point - purely seeking advice re. proposed method. i'll smooth out the response in the room once i know what technique to proceed with. [edit] sorry, i should make completely clear - i am proposing a rigid non-structural fully floating steel frame within the existing garage. [/edit] width = 2.7m, length = 4m, height = 2.9m - it's not huge. i'm leaving a 2.5m long section at the end for my workshop. three sides of the garage are wood, roof is tin, with one side bessa block adjoining the lounge/control room and a sloping concrete floor. i'm wondering if anyone has thoughts on floating a steel frame within the existing structure. i've got an engineering workshop just around the corner, so i'm thinking of getting them to weld up the 6 faces (four sides, roof and floor, with struts to level it off) and then i'll bolt them together, using high density rubber / neoprene blocks to float the whole thing out from each surface. then just the 'easy' job of lining with gyprock soundcheck over rockwool, fit second door , wire up power and signal cables and voila - floating instrument room. i'm after decent sound reduction at minimum wall width, hence floating the frame on rubber, filling all space with rockwool then lining with soundcheck. proposed usage is drums and guitars, but amps are all low-watt valve. no 100w stacks here! hmmmm. any flaws with tha cunning plan immediately apparent? it's bound to give me better isolation than lining the existing stud walls, and from my initial discussions with the welders it'll work out pretty [inexpensive]. but is floating metal frame the way to go? the garage dimensions don't give me the ability to build an extra set of block or brick walls, so i'm looking at minimum width with maximum isolation . . . someone else mentioned Hebel - whassat? warm regards and thanks in advance. chrisT. sager

Chris - check out this studio build. It's 70mm x 45mm pine stud with inside/out construction. viewtopic.php?f=11&t=6968&start=15

thank you john for getting back to me. that build is a very neat one, certainly. but due to the size room i have (2.7w, 2.9h, 4.0l) i'm asking about using floating panels made from C-section metal - i could maybe get away with 25mm + plaster. all cavities packed with rockwool. my loungeroom is the control room (a good large L-shaped room) with door through to the garage, so the garage build only need be a single space cabled through to the control room. doorway would be a double solid door. lounge/control room is all secondary glazed with 6.8mm laminated glass, so it's got very good isolation from the world. wall between lounge and garage is bessa block. i know in the 'must read' section, it clearly states to use existing methods, but a rigid non-structural metal frame would give me the opportunity to completely float all 6 faces on high density rubber which should be a win. is there no-one that has gone down the path of floating a metal frame construction? regards,

yes - but after you have built your metal frame, attached the drywall you then have to treat the room - in the inside/out treatment the wall also includes treatment. I just don't like the idea of metal framing, it will ring - maybe it's personal but I find timber a more pleasing material for studios. But you are welcome to go ahead with it.

point taken. i'll just drop the idea ans stick to timber. i can still float it. thanks,

John Sayers wrote:

yes - but after you have built your metal frame, attached the drywall you then have to treat the room - in the inside/out treatment the wall also includes treatment. I just don't like the idea of metal framing, it will ring - maybe it's personal but I find timber a more pleasing material for studios. But you are welcome to go ahead with it.

I agree with John completely here (as if that is surprising - can't think of a time where I ever disagreed with him - John is a pretty sharp cookie) - but would another reason for those who may be reading this - and that is because the steel frames most of you would end up working with are what is referred to as "Light Gauge Framing" typically 25 ga steel. These materials are great for high and mid frequency isolation - in fact a 4" LG stud wall with drywall attached to each of it's faces - is equivalent to a 2x4 wood stud wall, with resilient channel with the same number of the sheets of drywall in STC rating. BUT - that is where it ends - in order to control the lower frequency regions you need not only mass - but also stiffness, and for that you need structural steel framing - and even with structural framing - you will never achieve the stiffness you need with less than 4" heavy gauge members in normal height walls..... Stick with wood - and - if you have the room and want some extra bang for the buck - opt for 2x6 frame at 24" centers over 2x4 at 16" centers - the same number of board feet of lumber in the body of the wall (a slight increase in the plates) BUT - again - an increase in the isolation of low frequencies.......... Rod