Steel Garage Makeover

Hi All! With my re-found love of music, I’ve decided to convert my standalone steel garage into a jam/session/recording studio. The past few months have been spent reading, learning and planning how to build my studio and with winter coming I need to get started on at least the thermal insulation, so here I am looking for advice and direction on what I am proposing. I’ve decided to keep the garage as a single room, which I understand is a big compromise :( – but unfortunately there are other hobbies that need their space too. The upside is I can be quite flexible with regards to room arrangement using free standing partitions. ** Volume I’m the bass player in a band whose style ranges from sparse acoustic blues to very dynamic heavy rock, so safe to say we are dealing with upwards of 120db and a strong low end. This will all be confirmed once I’ve bought a level meter. The side of the garage shares the fence-line of a church car-park/basketball court. The rear of the garage is 15 metres from the neighbours house behind us, and the neighbours to the side are 10 metres from the garage. Fences are 6½ feet high. ** Existing The garage itself is based on a concrete slab and has a 3.0m x 0.75m x 1.75m pit in the centre (the original owner was a mechanic). Clean and simple steel frame construction with hat channel running the length of the shed, (along the top, middle and bottom of the walls) that sheet steel cladding is screwed to – minimalist at its best. At the moment I can’t even turn the stereo up without it sounding like a snare drum. • Side walls size: 7.2m long x 2.5m high • Back wall size: 5.4m wide x 2.5m high • Pitched Roof running front to back is 3m high in the middle Currently there is a tilt-a-door that I plan to replace with barn doors (outer). There is a full height door on the side of the shed that will be bolted/sealed shut and a louvre window that will need swapping out for something solid. ** Construction I have initially planned to put vapour barrier over all the sheet steel and put in thermal insulation (~60mm) to fill out level with the hat channel and to initially make the whole space a little more comfortable. At this stage I’d also be caulking all of the points where the steel frame touches the outside sheet steel to get rid of the rattle. From here I am a little lost as I don’t know the most effective method given my sound volume and terrible starting point. ** Budget Initially around $1000 get the first frame constructed, thermal insulation in and power relocated, with another $2-3,000 for plasterboard and sound insulation. ** Questions Do I build a timber frame on the floor using 90mmx45mm studs, screw 2-3 sheets of 16mm plasterboard to it (as well as rubber underneath and caulking all the joints), stand it up, and bolt to the existing steel frame, fill with sound insulation – then with an air-gap of 50-100mm, do the reverse, timber frame standing up, fill with sound insulation then screw 2-3 sheets of 16mm plasterboard to it? or Do I build a freestanding timber frame sitting 25-50mm in from the existing steel frame using 90mmx45mm studs, fill the stud space with sound insulation and screw 2-3 sheets of 16mm plasterboard to each side? (Build the frame on the floor, screw plasterboard on, stand-up - with plasterboard facing out, fill with insulation, then screw plasterboard to the inside). or Do I build a frame using 90mmx45mm studs and attach it to the existing steel frame, fill the stud space with sound insulation and screw 3 sheets of 16mm plasterboard on – and treat that as my starting point before building the room inside? I have allowed for losing ~250mm on each wall and ~150mm on the ceiling, but would like to keep the room as big as possible. The part I’m finding confusing is whether to have plasterboard or timber frame as the first material facing the existing steel frame/cladding? Whatever is done for the walls will be closely approximated for the ceiling, but first I need to determine the amount of weight I need to deal with so that I can get busy and build the right strength frame to hold the ceiling safely. I need to insulate soon as it’s getting bloody cold outside at night! Thanks in advance, Ben

Still getting the hang of sketchup, but here's a couple of pics... The first one is what I think will work for the walls. I don't know if this qualifies as a three leaf system as there is no mass on the outer leaf. The reason for cutting the outside timber frame into the existing hat channel is to save some space and give the insulation a frame to sit within, as well as a mounting point for the plasterboard. The second one is a simplified view of the garage.

Just bumping this up. Is there anyone out there who has been in the same situation able to give me any advice on the best way to attack a steel shed?

Forget about the steel being a leaf, it's not airtight anyway. Add a layer of drywall to the inside of the horizontal channels that support the steel and seal it to a similar layer that follows the ceiling channels and seal it airtight. Then build a room within a room inside it with insulation in the cavity.

Thanks for clearing that up for me John. My initial concern was needing sufficient 'framing' support for the plasterboard on the ceiling and walls as I'll need 2 x 16mm sheets - but with your response I understand I can get the sheets up, sealed airtight and with good interim ceiling supports in place, build the timber frame to permanently hold them.