Stand alone studio build ORANGE NSW

Hi everyone. I am just embarking on the design phase for a 2 room studio that will include a live room and control room ...but it’s time to add some expertise to my enthusiasm! I have been searching through the forum for relevant info and waded through (a number of times) “Build it Like a Pro” and the Master Handbook of Acoustics. I am located just outside Orange (3 ½ hours from Sydney) and am in the process of lodging documents to gain approval to demolish my existing zincalume shed and to build a replacement, which will house both my studio and a general workshop. The plan is to purchase and erect a zincalume (herein referred to as tin) roofed open “hay shed” erected on a concrete base and build the studio/workshop under that canopy. I’ve taken this route as it presents a more simple path for regulatory approval notwithstanding the fact that I need to do some work to bring the transmission loss performance of the roof up to that of the walls. A lot of what I’m doing is based on Stevev’s posts on the “Dog and Bear“ build. Isolation wise, I face very similar circumstances to the “Dog and Bear” build with expected inside measurements up to 115dB and my nearest neighbour at 25/30m – I’d like to be at 40dB by the time I hit his back wall. My inside measurements are based off my own band (drums, bass, guitars and vocals) using my omni and REW software in my old garage and Stevev’s calculations in his build. Key elements of the draft design: a. The slab will be 10.1m x 12.5m (100mm thick aside from deeper piers where the block walls sit) and the tin roof will have the same coverage; b. The Hay shed frame is 150mm galvanised steel C section and under the current plan it will have no touch points with any of the walls; c. The “outer shell” (block/concrete wall) has external dimensions of 10.0m x 10.34m - the cement blocks I'm looking at are 190mm wide and my intention is to render the outside of that wall; d. Inside the cement block wall will be two isolated rooms – a live room and control room, both having internal dimensions of 6.1 x 4.5 x 2.9m (h). There will be a window between the two rooms – though I’ve yet to draw that in. The gap between the rooms and the inner & outer leaf and the two rooms is planned at 150mm and I intend to use Bradford Soundscreen insulation at 110mm and 24kg/m3 in the gap; e. The middle leaf roof (that which encloses the block wall) is planned to be 2 layers of fyrchek (16mm) with green glue in the middle. Sitting on that I intend to use Bradford Soundscreen insulation. The frychek will be attached to beams that rest on top of the block wall and the extra dividing wall between the workshop and studio rooms. Green glue will be applied to the joins between fyrchek and block wall. Straight out of Stevev’s project! (without the RC). (Note that the wood framed superstructure holding the middle leaf ceiling in the drawings is a guess in terms of spacing and dimensions – I’ll take further advice from my engineering mate on those dimensions before it is finalised.) f. The area within the block walled space not occupied by the live room and control room will be my workshop/storage area. I am intending (subject to feedback) to incorporate an additional wood studded fyrcheck wall between the storage/workshop area and the internal room walls. Thinking behind the “additional wood studded fyrcheck wall” Proposing this is largely to (hopefully!) avoid having to do windows and doors within that space to the TL capability of the block wall. What this means is that I have 3 leaves on the workshop side – the inner woodstud/fyrchek leaf, the “additional wood studded fyrchek wall” and then the block wall on the very outside. The distance between the “additional wood studded fyrchek wall” and the block wall (front) is 3.675m. I’ve framed a question below on this – my thinking is that this is the type of arrangement is the same as I’ve seen applied to basement studios where the rest of the room was being used as a laundry or for heating etc and that the 3rd leaf is a reasonable distance from the “additional wood framed fyrcheck wall”. That said, I’m sure there is much more experience out there on the validity of this approach or how it should be modified to make it work. I’ve attached some sketchup concept drawings that show a rough design and the start of the ceiling isolation plan – what I think will be referred to here as a middle leaf of the ceiling - and the top of the inner ceiling. Initial think on budget is anything up to 50k but I need to close off isolation and engineering requirements before that gets firmed up. As indicated, I have the assistance of an engineer mate of mine with respect to wall construction/ceiling loads/design. My initial goals are to know enough about the isolation requirements/issues for the outer shell so that the regulatory approval documents don’t need later adjustment. From there I can refine the internal design in parallel with (and following) the approval process. QUESTIONS So what I’m looking for right now is advice on: 1. Uncovering the “holes” in my proposed design; 2. Suggestions about how to do it more efficiently/effectively; 3. The impact of having the workshop space between the internal rooms and external walls and the introduction of the “additional wood studded fyrcheck wall” to compensate. 4. Whether I have material flanking issues from: a) having the columns of the “hayshed” inside the workshop space; and b) while it is not planned to be the case, if the final design requires some contact between the block wall and the “Hay shed frame” Looking forward to feedback and correction as required. Andrew

gearjunk1e wrote:

Hi everyone. I am just embarking on the design phase for a 2 room studio that will include a live room and control room ...but it’s time to add some expertise to my enthusiasm! I have been searching through the forum for relevant info and waded through (a number of times) “Build it Like a Pro” and the Master Handbook of Acoustics. I am located just outside Orange (3 ½ hours from Sydney) and am in the process of lodging documents to gain approval to demolish my existing zincalume shed and to build a replacement, which will house both my studio and a general workshop. The plan is to purchase and erect a zincalume (herein referred to as tin) roofed open “hay shed” erected on a concrete base and build the studio/workshop under that canopy. I’ve taken this route as it presents a more simple path for regulatory approval notwithstanding the fact that I need to do some work to bring the transmission loss performance of the roof up to that of the walls. A lot of what I’m doing is based on Stevev’s posts on the “Dog and Bear“ build. Isolation wise, I face very similar circumstances to the “Dog and Bear” build with expected inside measurements up to 115dB and my nearest neighbour at 25/30m – I’d like to be at 40dB by the time I hit his back wall. My inside measurements are based off my own band (drums, bass, guitars and vocals) using my omni and REW software in my old garage and Stevev’s calculations in his build. Key elements of the draft design: a. The slab will be 10.1m x 12.5m (100mm thick aside from deeper piers where the block walls sit) and the tin roof will have the same coverage; b. The Hay shed frame is 150mm galvanised steel C section and under the current plan it will have no touch points with any of the walls; c. The “outer shell” (block/concrete wall) has external dimensions of 10.0m x 10.34m - the cement blocks I'm looking at are 190mm wide and my intention is to render the outside of that wall; d. Inside the cement block wall will be two isolated rooms – a live room and control room, both having internal dimensions of 6.1 x 4.5 x 2.9m (h). There will be a window between the two rooms – though I’ve yet to draw that in. The gap between the rooms and the inner & outer leaf and the two rooms is planned at 150mm and I intend to use Bradford Soundscreen insulation at 110mm and 24kg/m3 in the gap; e. The middle leaf roof (that which encloses the block wall) is planned to be 2 layers of fyrchek (16mm) with green glue in the middle. Sitting on that I intend to use Bradford Soundscreen insulation. The frychek will be attached to beams that rest on top of the block wall and the extra dividing wall between the workshop and studio rooms. Green glue will be applied to the joins between fyrchek and block wall. Straight out of Stevev’s project! (without the RC). (Note that the wood framed superstructure holding the middle leaf ceiling in the drawings is a guess in terms of spacing and dimensions – I’ll take further advice from my engineering mate on those dimensions before it is finalised.) f. The area within the block walled space not occupied by the live room and control room will be my workshop/storage area. I am intending (subject to feedback) to incorporate an additional wood studded fyrcheck wall between the storage/workshop area and the internal room walls. Thinking behind the “additional wood studded fyrcheck wall” Proposing this is largely to (hopefully!) avoid having to do windows and doors within that space to the TL capability of the block wall. What this means is that I have 3 leaves on the workshop side – the inner woodstud/fyrchek leaf, the “additional wood studded fyrchek wall” and then the block wall on the very outside. The distance between the “additional wood studded fyrchek wall” and the block wall (front) is 3.675m. I’ve framed a question below on this – my thinking is that this is the type of arrangement is the same as I’ve seen applied to basement studios where the rest of the room was being used as a laundry or for heating etc and that the 3rd leaf is a reasonable distance from the “additional wood framed fyrcheck wall”. That said, I’m sure there is much more experience out there on the validity of this approach or how it should be modified to make it work. I’ve attached some sketchup concept drawings that show a rough design and the start of the ceiling isolation plan – what I think will be referred to here as a middle leaf of the ceiling - and the top of the inner ceiling. Initial think on budget is anything up to 50k but I need to close off isolation and engineering requirements before that gets firmed up. As indicated, I have the assistance of an engineer mate of mine with respect to wall construction/ceiling loads/design. My initial goals are to know enough about the isolation requirements/issues for the outer shell so that the regulatory approval documents don’t need later adjustment. From there I can refine the internal design in parallel with (and following) the approval process. QUESTIONS So what I’m looking for right now is advice on: 1. Uncovering the “holes” in my proposed design; 2. Suggestions about how to do it more efficiently/effectively; 3. The impact of having the workshop space between the internal rooms and external walls and the introduction of the “additional wood studded fyrcheck wall” to compensate. 4. Whether I have material flanking issues from: a) having the columns of the “hayshed” inside the workshop space; and b) while it is not planned to be the case, if the final design requires some contact between the block wall and the “Hay shed frame” Looking forward to feedback and correction as required. Andrew

Hi Andrew, The "third" wall that you're concerned with is not a concern at all, it is not a third leaf due to there being a rather space between it and the outer block wall. This will actually increase your isolation in this instance. In effect, your control room and tracking room will both be isolated from the outer space around them, as well as the outside world (presuming all goes to plan). Shame not to use the whole space for the studio though, but I understand you need a workshop as well. It all looks quite good so far, I'm assuming the tin roof will have ventilation due to the nature of its corrugations? What I am unsure of is if that will be enough ventilation to prevent condensation or if the boarded up middle leaf will need additional ventilation as well, which of course will need to be designed properly as to not compromise your isolation. If you find out how one would normally vent such a space in a residential setting then we can convert that method to be used on a studio. The only other comment I have is regarding your choice of insulation in the cavity. There is no advantage to using specialist sound or acoustic insulation here, you can just use the cheapest, lowest density, fluffiest, itchiest insulation you can find. If the insulation that you mentioned is already cheap and easy to source then go for it, but I expect ordinary attic roll will be cheaper. Paul

Paul Thanks for the quick reply - I'd hoped that extra wall was OK - it seemed to make sense to me but comforting to get confirmation :) Re ventilation - I will have to address HVAC - I need to find out from Stevev how he went with the Daikin units he installed. Its a natural starting point for me given the similarities. On the insulation - thanks - I've used that Bradford type before for room treatment and its pretty price competitive with the fluffy but your point is well made Andrew

gearjunk1e wrote:

Paul Thanks for the quick reply - I'd hoped that extra wall was OK - it seemed to make sense to me but comforting to get confirmation :) Re ventilation - I will have to address HVAC - I need to find out from Stevev how he went with the Daikin units he installed. Its a natural starting point for me given the similarities. On the insulation - thanks - I've used that Bradford type before for room treatment and its pretty price competitive with the fluffy but your point is well made Andrew

I am not talking about HVAC, I'm talking about your structural venting so that it doesn't rot out. A Daikin mini split has little to do with this. Your HVAC is a separate issue that will need to be addressed as well. Paul

Hi Paul Thanks for following up on this. I will admit I hadn't been particularly concerned about the ventilation into the roof space. The reason being that I'd understood the zincalume roof was not particularly relevant in the isolation chain ie the inner room and "middle leaf" were really doing the work, so I'd thought a pretty residential standard finishing of the roof structure - for example - a an A shaped wood framed fibre cement cladding between the top of the block wall and roof line at the ends would suffice. A finish like that would provide plenty of air flow through the roof space. Sounds like I need to rethink this :oops: Andrew

gearjunk1e wrote:

Hi Paul Thanks for following up on this. I will admit I hadn't been particularly concerned about the ventilation into the roof space. The reason being that I'd understood the zincalume roof was not particularly relevant in the isolation chain ie the inner room and "middle leaf" were really doing the work, so I'd thought a pretty residential standard finishing of the roof structure - for example - a an A shaped wood framed fibre cement cladding between the top of the block wall and roof line at the ends would suffice. A finish like that would provide plenty of air flow through the roof space. Sounds like I need to rethink this :oops: Andrew

It might be fine, with your climate and code, I am just asking you to check it out first before it's constructed. So let me explain a little more; You're right, the tin roof is not part of your isolation, it is simply a rain screen to keep your two leaf system dry. The tin is not really a leaf at all. The danger is if what you're calling your "middle leaf" roof deck ALSO reaches the same temperature as outside, as that can potentially cause interstitial condensation to form in the cavity (between the inner and outer leaf). This is what I personally am not sure about, since I have no experience with it. In the UK, we have cold winters and warm summers (if we're lucky). What can happen is during the winter the warm air inside the building will rise up carrying moisture from sweat, breath, water from taps, kettle steam etc. This water vapour has potential to travel through the ceiling up into the loft space and if there is no ventilation in the loft space and there is insulation between the rafters/joists, then water droplets will form on the cold underside of the roof deck behind this insulation and it will stay there with no where to go. It forms mould and rots out the timber and roof deck and this all goes on without you knowing about it since it cannot be seen, until one day the temperature changes and it all starts dripping down through the ceiling and all over the floor by which time is it too late and you have to replace the entire roof and ceiling. I know this from first hand experience unfortunately! Now, yes, your tin is nice and ventilated, but you may be trapping moisture between your inner and outer leaf since that will be heavily insulated on the inside, but the layer of ply or OSB or whatever you will have directly under the tin will presumably be subject to the same temperature as the tin? and that layer will have to have some sort of vapour control layer on top of it before you install the tin. If that vapour control layer does not allow vapour to travel through it (such as roofing felt for example) then all the moisture will be trapped. There are really simple ways to prevent this which won't mess up your isolation at all, but we need to find out from someone in your part of the world who specialises in building roofs so that you can propose your roof assembly to them and they can tell you if it's going to be a problem or not regarding interstitial condensation. I've attached a diagram I've drawn of one way to do a ventilated roof and maintain isolation, at least in the UK. It might be helpful to you? Paul

Hi everyone I've got some further clarity on my design and compliance issues.... which revealed a nasty surprise for me :cry: I'm trying to work out a solution - so any help would be appreciated The issue arising is that the frames for the zincalume roof I have planned will require more substantial haunches (or knees) on the two middle frames than I'd hoped and this would mean: a. To maintain my targeted air space, I will have to have a raked ceiling* in my inner rooms for about 600mm of the length (10%) - not a huge issue IMO - just annoying; but also, more importantly (maybe??) b. It means my 3rd leaf definitely contacts my 2nd as the frame haunches (knees) will come through the block wall as per the attached pic QUESTION: My gut feel is that the fact that the 3rd leaf is of such minimal isolation value that if I green glue around the the ingress of the haunch insertion through the block wall I won't lose isolation - but I would like to get a far more informed view of this assumption. I'm I right or off the plantation? Thanks in advance Andrew * - the height at the low point of the rake for the internal room would be 2.612m running up to the rest of the room height at 2.994m

Any advice out there? Sorry to be pushy - I know everyone has "day jobs" here and people contribute in their spare time.....but I can't work out any way to avoid have at least one knee of the frame supporting the zincalume roof coming through the outer leaf (block wall) ......without reducing the footprint of my rooms or my workshop space :( The good news is that I have made some progress by re-engineering the design to incorporate thicker frames so I can have just one intermediate frame rather than two - but the fundamental question :?: remains whether contact between the roof supporting frame and the block wall will negatively impact isolation I had hoped that I could resolve this "at leisure" but my engineer mate tells me I need to settle the relationship between the frame and block wall so he can finalise the footings plan for regulatory approvals So any feedback would be gratefully received! Andrew

Hello & howdo' Andrew? I'm not certain that I have completely understood your dilemma, but if I were to summarise the problem like this, would I be close? **The requirement for structural reinforcement of the existing roof will cause a flanking path between the middle (outer) leaf of your studio and the roof? ** Please correct me if there's something I've missed - I know that time is against you and I'm sure you'll have asked your SE if there is an alternative to using the frame haunches but if you have to go via this route, perhaps there is a way of isolating the reinforcing members where they connect with the outer wall and roof as well as the measures you have suggested (rubber mounting blocks??). As you stated, the 3rd leaf has no or little isolation value but I would consider the possibility that the flanking path might effectively turn your tin roof into a massive resonator at certain frequencies and you definitely don't want that! It's difficult to judge without looking at your Sketchup drawing but alternatively, perhaps there is a way of building around the problem - that is to say altering the layout of the isolated space to avoid the added reinforcement? You may find that a relatively small adjustment will eliminate the problem altogether. I notice that the gap between the inner leaves of your live room and control room appear to line up with one of the joists that need to be reinforced. Maybe a vertical beam placed in the void to support the joist would obviate the need for at least one of the haunches? I hope an experienced builder will come forward with their thoughts but in the meantime I hope you figure it out and get the result you want. ATB John.

John Thanks...you have restated the problem accurately and more efficiently than I :oops: . I'm busy updating the sketchup diag at present but you are correct - the middle frame will now sit over the gap between the two rooms so we could drop some upright supporting columns down between the rooms to replace the knees and brace that are there now. The middle supporting frame would then look like the two end ones. Let's see if our builders have any other perspectives Andrew

John Here is what I think you were alluding to I hope my screen shots pick it up. I've included part of the inner leaf ceiling over one of the rooms - but I have hidden the 2nd leaf ceiling so that it is clearer where the columns will sit between the rooms. I have left the wall in that will sit between the studio rooms and my workshop. There will need to be some fine tuning here - the gap between the rooms may need to be widened and I may need to trim the width of the rooms a little to get to 150mm gaps and to allow for the fact that my columns will all be 76mm wide and 250mm deep rather than the 50mm wide and 150mm deep as is in the ketchup model at present. Andrew

Yes, that's what I was driving at Andrew, although I confess I had only considered a single upright. I'm no engineer but I would have thought two uprights would bridge the load more effectively. I don't believe that you would have to increase the air-gap between the rooms along the whole length of the wall, only around the space that the uprights occupy - if that makes sense? Looking at your screen shots made me wonder if putting two further uprights (connected to the joists at the far end of the room depicted without a ceiling) would make it possible to bridge the load of your added mass without losing any height from either room - sort of like this? (excuse the crude illustration).

It's a non issue - the "third leaf" is not really a leaf at all, it's just a rain screen to keep your double leaf assembly dry. As long as none of it touches your most inner leaf for the control room or tracking room then you're good to go. Paul

Paulus87 wrote:

It's a non issue - the "third leaf" is not really a leaf at all, it's just a rain screen to keep your double leaf assembly dry. As long as none of it touches your most inner leaf for the control room or tracking room then you're good to go. Paul

Paul Brilliant, thanks...the whole flanking thing has me spooked...I get that a common wall, frame or duct will transmit sound but beyond that it is a bit of a mystery (to me!) esp with the 3 leaves...my initial thinking was to ignore the roof and it seems I just need to hold on tight to that view Certainly the inner walls WILL NOT have any contact That said, it may make it slightly easier for construction purposes if I switch to having the two columns rather than the knees and brace. BTW - I am still chasing down that "between leaf" ventilation issue you raised with my engineer mate...in Orange we do get some temperature variations - winter night temperatures down to -5 (mostly +3 to minus 3 in the depth of winter) but better to be safe than sorry Andrew

...the whole flanking thing has me spooked...

Me too.

. . . it may make it slightly easier for construction purposes if I switch to having the two columns rather than the knees and brace.

Which is a good reason to consider it. Let us know where you land Andrew.

John Thanks for your thoughts on the 2nd leaf ceiling..timely as once i settle the middle frame i can get back to that design. BTW, the 2 columns is really only because it matches their end frames which makes it a standard product which is warranted by the supplier against code here. Once I have settled things this week i'll be posting a revised design and pick up on the HVAC design elements we discussed on your blog Andrew

Hello everyone! Long time since my last post - due to a rethink: not the layout or inner rooms’ construction nor concrete base, but a rejig of the outer wall construction. It’s still a “room in a room” per John Sayers. For the outer wall, I’ve moved from cement blocks to a wood framed wall, clad on the outside with a 0.42mm Corodek (steel) skin and a 3 layer outer wall fixed to the inside of the studs – one layer of plywood/16mm Frychek (drywall) and 2 layers of 19mm yellow tongue (structural grade particleboard sheet). Why change? The cement blocks were going to be harder to DIY/more expensive and the more I searched the site, it gradually dawned on me that I could achieve similar isolation from this new wall design together with what I’d planned for the outer ceiling anyway – a 2x fyrchek outer ceiling with green glue between the ceiling layers. The mix of ply and Fyrchek on layer one of the outer wall is due to engineering requirements to employ structural bracing of the timber frame at intervals with ply; rather than use the more expensive ply for the whole outer layer, I’m only using ply where I have to and fyrchek elsewhere on layer 1. The use of Yellow tongue particle board as the 2nd and 3rd layers for the outer wall is because it’s cheaper than Fyrchek. (I may still revert to layers 2 and 3 being Fyrcheck as the yellow tongue standard supply width means more joins/caulking than Fyrchek.) I included sketchup images to hopefully help with explanations/context. While I’ve spent countless hours on research, there are probably some rookie errors in here somewhere so please don’t hold back in correcting me where any of my logic or design is faulted. SPECIFIC QUESTIONS 1. Technically, I have a 3 leaf structure on the roof (as before) and now on the walls as well. Paulus87 replied to my initial post essentially confirming that this is more a technical observation than a practical concern - as relating to my initial design. My understanding is that the argument is that the outer skin (0.42mm steel) is of low mass (4.35kg/m2) and there is substantial airflow between it and the first layer of isolation – therefore it can be ignored in practice. Q; Please let me know if that conclusion is faulted given that the steel skin and the first layer of the outer wall is NOW only separated by 90mm – the width of the studs. I’ve included below a close up of the wall construction to help. 2. My studio is in fact a wood frame structure built under a steel “hay shed”. Since dropping the cement block wall concept I’ve spent hours designing how I’ll build my outer walls around the steel columns that support my roof (the pics below shows how I planned to construct the Ply/Fyrchek/particleboard layers around the columns – both the side and back columns together with some images of the framing). I’ve since wondered whether I am over engineering this. Steel is 10x denser than Fyrchek/drywall which made me think that I could use the steel in the columns as part of the outer wall – specifically, to butt the Fyrchek/particleboard layers up to the columns and use an acoustic sealant in the join between the Fyrchek/particleboard and the steel. (see final pic below) Q: Will the use of the steel column in this manner compromise isolation? 3. The one area I could see as a vulnerability with the design above is that there is no staggered join where the Fyrchek/particleboard layers butt up against the column – if this is an issue I could adopt the following to provide some “insurance”. Q: is this worth it/necessary? Resolving this will settle the sizes of my rooms. Currently I have ~200mm between the inner and outer walls except where the boxing of the columns in my current design “pushes in”. If the steel can form part of the outer wall then it’s all cruisy… Thanks again for sharing your experiences Andrew BTW - Paul, I have worked with my engineer and incorporated a layer of reflective foil laminate backed insulation used here to address the concerns you raised

Hi I've been busy constructing the outer shell of the building the issues I've raised here have not got in the way of my plans .......but decision time is looming! Anyone got any insights for me? Andrew

it's not clear what your concerns are. you've created an outer shell with mass, damping, moisture control, and designed a decoupled inner pair of shells - presumably using properly size joists for the spans, and appropriate vertical framing to support a few tons of material overhead. so that all looks good. missing: HVAC plan including outdoor ventilation required for keeping people alive in a hyper-insulated set of rooms. and which should be wholly separate from the workshop to avoid noxious fumes, dust, etc (plus it's probably lower cost to keep that space temperature/humidity etc controlled. the HVAC in the studio must run fulltime when occupied. doors windows etc all need to match isolation mass and be sealed. heavy doors need closers to ensure safety. recommend emergency light in rooms esp if no windows. for more safety - consider what happens to occupants if the fire is in the workshop (probably more likely than say spontaneous combustion from a musician playing the God riff) how do you exit? fire suppression? alarms? etc. no one can hear you scream in a soundproof room...

Glenn Thanks for the feedback...looking back through my previous post I think I could have been clearer :oops: Also I appreciate the safety perspective :D loss of power in a fully enclosed room would be fun! I'll step through your comments and clarify my concerns at the end

gullfo wrote:

it's not clear what your concerns are. you've created an outer shell with mass, damping, moisture control, and designed a decoupled inner pair of shells - presumably using properly size joists for the spans, and appropriate vertical framing to support a few tons of material overhead.

Yep - the wall/ceiling designs are have all engineering sign-off.

gullfo wrote:

missing: HVAC plan including outdoor ventilation required for keeping people alive in a hyper-insulated set of rooms. and which should be wholly separate from the workshop to avoid noxious fumes, dust, etc (plus it's probably lower cost to keep that space temperature/humidity etc controlled. the HVAC in the studio must run fulltime when occupied.

Agreed - I was trying to break this down into chunks rather than do one large post. I'll post later on the HVAC plan in detail but for now my plan is to run a ducted mini-split in the space between the outer leaf ceiling and the metal roof with ducting and 4 outer wall silencers in the roof space between the outer ceiling and metal roof and the inner leaf silencers penetrating the inner room ceiling. I've done enough work on that to get comfortable that I can fit in my silencers in.

gullfo wrote:

doors windows etc all need to match isolation mass and be sealed. heavy doors need closers to ensure safety. recommend emergency light in rooms esp if no windows.

Yep - understood on doors - I've done some early work on that but need to hone in when I get to detailed framing design. Safety light - good call...sounds like the voice of experience

gullfo wrote:

for more safety - consider what happens to occupants if the fire is in the workshop (probably more likely than say spontaneous combustion from a musician playing the God riff) how do you exit? fire suppression? alarms? etc. no one can hear you scream in a soundproof room...

“Workshop” may be an overstatement of use...it’s really a man cave - workbench, beer production and storage of mowers etc. There won't ever be anyone using the workshop while the studio is in use but some more thought on fire safety/exit is worth a stop and think To my concern There are 5 points where I am using the part of the 2.4mm steel C section columns as part of the outer leaf but these columns also extend into the air gap between the outer and inner walls and extend above the outer ceiling. Two questions flow from this: a. whether I am compromising my isolation at all by taking this approach; and b. whether I need to measure the air gap between the inner and outer rooms from the drywall to drywall as you would with a drywall/wood stud construction OR measure it from the most inner part of the steel C-section For now I'll just focus on the first question and I’ll use one of the columns on the side wall as an example- noting that I’ve changed my construction approach very slightly from the post you replied to – using some treated pine on the inside of the steel C-section: Here’s some sketchup close ups showing the outer leaf consisting of drywall (Fyrchek here in OZ) butting up against the steel C-section And one more showing how the steel C section column joins the outer leaf ceiling What is worrying me is whether the fact that the steel C-section column is 1. part of the outer leaf 2. extends to within the air gap; and 3. extends beyond the outer ceiling line is problematic in terms of isolation - flanking is my worry here. Do I have anything to worry about or am I overthinking (or maybe underthinking it)? Hope this is clearer than before! Andrew

yes much clearer - :) on the column - as long as it's not part of the inner walls and ceiling, then there should be little problem. if you do connect it to the inner walls, ceiling, inner frame etc, then yes, you will have coupled them and thus loss a significant amount of isolation. if you need to stabilize the inner frame - isolation sway bracing is the answer - Mason Industries and Kinetics Noise have products to handle that requirement as well as detailed specs and drawings on using them.

Glenn Thanks for that - and for the advice on the stabilization solutions - I've yet to give detailed thought to the inner rooms but that will come in time I'll admit I've been struggling with understanding flanking; when I was editing those pics in my last post and adding all the arrows with the sealant points it probably should have dawned on me that by leaving a small gaps at joins and filling with acoustic sealant I am decoupling from any of the structural elements that support the outer leaf :oops: In terms of leaf 1 and 2 coupling, I've been at pains to ensure that there is absolutely no contact - my air gap objective is 200mm - based on the isolation needs. That leads me to the question I left behind in the last post which is how to think about the steel C-section columns in relation to the air gap. I know that the air gap is normally measured from leaf face to leaf face ie ignore the studs provided there is at least a 1" gap between the inner and outer leaf studs per pic below Q; Am I right in thinking that I can apply this approach in relation to my steel C-section columns? - this would means the outer layer of my inner room needs to be at least 1" from the steel C section Thanks again for your time and expertise Andrew

the air gap is the depth of the wall (or ceiling) framing + the gap between framing of inner and outer rooms. effectively the mass-to-mass distance. so a 2x6 wall (at least in US) is 5.5" + 1" gap + 5.5" would be a 12" air gap. so you'd fill in that gap with 12-14" of soft insulation depending on the batts sizes available, probably better to squeeze a slightly thick amount of soft insulation to ensure full contacts with the mass layers/vapor barrier, etc.