Room within a room within a shed (advice please)

Hi Everyone, First thanks to everyone who has asked and answered questions on this forum. I've learnt a lot trawling through many peoples problems and projects. What do I want to build? I have a shed (sitting on a 110mm concrete slab) that is 12m wide by 16m long by 3.6 high (at the shortest). I want to take approximately 1 quarter of this space (i.e. 6m x 8m) and turn it into a rehearsal room/home recording studio/home office. My ideal goal would be to play in the room at any time of night without disturbing my family in the house maybe 20m away (and of course the neighbors who are perhaps 50m away but with direct line of sight). Instruments would include drums and electric bass (I'm guessing beyond those it doesn't matter too much what the other ones are). I've not done any sound meter measurements (yet), we can get pretty loud, but I guess about 100db is a common assumption for drums? (I'll aim to buy a sound meter and get some more concrete numbers here). Rough overview of the shed and proposed floor plan Plan so far: Build a room within a room within the shed using wall construction as per the attached pic i.e. from outside in:

• 2 x 13mm plasterboard
• 90mm wooden stud frame packed with insulation
• air gap
• 90mm wooden stud frame packed with insulation
• 2 x 13mm plasterboard

I was planning to start with 2 x plasterboard, but be prepared to add additional layers both internally/externally if required. I'm hoping this approach should be ok for the two walls facing into the middle of the shed. I'm not so sure about the 2 walls that will face the shed walls as I guess we are getting into 3 leaf territory here. To further complicate things, I want to have some externally facing windows (I already have window sets that came with the shed, but open to changing/modifying these). The existing shed wall construction (from outside in) is:

• 0.5mm painted corrugated steel (0.42 BMT)
• 50mm foil backed fibreglass anti-condensation blanket
• 100mm steel girts (horizontal)
• 100mm steel post (vertical)

(see image for example - worth noting that the anti-con blanket is sandwiched tight between the girts and the cladding such that it bulges into the spaces between). Alternate approach One other option I'm playing with is to break the "home office" space off into it's own area. It's more important to have windows in this office space as unfortunately I will spend more time "working" here than "playing" in the studio space. It's also not necessary to have high levels of isolation, so the window construction is simplified. See below pic for this approach - I guess this approach would remove alot of complications/costs with windows and allow the studio walls to move away from the shed wall (how far would be enough to avoid 3 leaf effects?) Budget I haven't put a lot of thought into the budget yet, but was thinking around the $5000 AUD mark (around $3500 USD at time of writing). I'm in the process of starting to cost up some of the raw materials and we'll see how naive I'm being. Questions: So I guess key questions would be: - Is the MSM wall construction approach generally ok? - Any issues with both the inner and outer wooden frames directly coupled to the concrete slab? - How best to interface with the shed walls? (or how far away from the shed wall does the external leaf need to be to avoid 3 leaf effects). - What would be a good internal height to aim for? Many thanks in advance for any help here. Duncan

donkey wrote:

Questions: So I guess key questions would be: - Is the MSM wall construction approach generally ok? - Any issues with both the inner and outer wooden frames directly coupled to the concrete slab? - How best to interface with the shed walls? (or how far away from the shed wall does the external leaf need to be to avoid 3 leaf effects). - What would be a good internal height to aim for? Many thanks in advance for any help here. Duncan

Hi Duncan, Welcome, brilliant first post - you provided all the info we need and some very clear designs and pictures, well done! What a nice space you have, you're very lucky. Is that the absolute maximum space you want to allocate to the studio section of the shed? It's a good size but of course, if you can make it even bigger then I would definitely do so! I get the feeling the main purpose of the "studio" is primarily a rehearsal space, so I take it that a separate control room and tracking space are not needed? Also, I take it that the shed as it stands is fully air tight and insulated and therefore no roof ventilation is needed? - Is the MSM wall construction approach generally ok? Yes, it looks good so far. Perhaps consider using 15mm fire rated drywall and perhaps you could make the air gap a little bigger if you can afford the space? As it stands you have a 220mm air gap (measured from drywall - drywall) which is quite good but since you require high levels of isolation all the way down the frequency spectrum I would knock it up to ~330mm. This will take up a little more space, but will provide you with better transmission loss at lower frequencies. If you were to position the studio in the centre of your shed then you would have all that extra space around it, in which case such a large air gap would not be necessary, but since you want to position it in a corner of the shed the extra air in the air gap will help. - Any issues with both the inner and outer wooden frames directly coupled to the concrete slab? In short, no as it is slab on grade (damped by the earth) and it is pretty thick. - How best to interface with the shed walls? (or how far away from the shed wall does the external leaf need to be to avoid 3 leaf effects). Don't worry about it - the shed walls/ceiling for the most part are very far away from your proposed studio. This will not create a triple leaf. It's best to view your shed as a gigantic rain screen around your studio to keep it dry. Two of the walls will be close to the shed walls, but the shed is quite lightweight and heavily insulated already. And the metal framing of the shed means that you will have to build the studio at a fair distance from the metal cladding anyway. If you are really concerned about it then build the studio a couple of feet away from the metal cladding. But I wouldn't worry about it. - What would be a good internal height to aim for? Well, that depends on how clear you want the recordings/mixing to be. If the recording side of your work is not of primary importance, then any height will do for a rehearsal space. If you'd like a decent recording space then as high as possible (within reason) e.g. more than 4m. Or for a decent mixing room, a height of around 3.3m is quite ideal, so for a hybrid room a height of 3-4 meters is a good compromise to aim for. It looks like that's what you're currently aiming for anyway, so that's great. Hope that helps for now? - all that's really missing from your plan now is a HVAC plan and a treatment plan. Oh, and I hate to tell you this but I highly suspect it will cost a lot more than your estimate. The outer weather proof part and concrete is already done, so that's a huge saving, if you can get great deals on materials and perhaps source some stuff second hand and do all the work yourself (or with free labour) then I think you could build it for about double your current budget. Though perhaps where you are everything is a lot cheaper than here in the UK? Looking forward to this one coming together! Paul

Hi Paul, Thanks for the super quick reply on this and the useful input.

Paulus87 wrote:

I get the feeling the main purpose of the "studio" is primarily a rehearsal space, so I take it that a separate control room and tracking space are not needed?

Yep, that is correct. Potentially the office space (if broken off to it's own independent area) could double as a control room down the track.

Paulus87 wrote:

Also, I take it that the shed as it stands is fully air tight and insulated and therefore no roof ventilation is needed?

It's pretty well sealed and insulated, but that makes me think I probably do need some form of ventilation. I'm thinking just vents (not active/forced ventilation) would be enough?

Paulus87 wrote:

- Is the MSM wall construction approach generally ok? Yes, it looks good so far. Perhaps consider using 15mm fire rated drywall and perhaps you could make the air gap a little bigger if you can afford the space?

Sure, will go with the 15mm fire rated drywall and I think we can definitely make the air gap ~330mm.

Paulus87 wrote:

- How best to interface with the shed walls? (or how far away from the shed wall does the external leaf need to be to avoid 3 leaf effects). Don't worry about it - the shed walls/ceiling for the most part are very far away from your proposed studio. This will not create a triple leaf. It's best to view your shed as a gigantic rain screen around your studio to keep it dry. Two of the walls will be close to the shed walls, but the shed is quite lightweight and heavily insulated already. And the metal framing of the shed means that you will have to build the studio at a fair distance from the metal cladding anyway. If you are really concerned about it then build the studio a couple of feet away from the metal cladding. But I wouldn't worry about it.

I assume the key thing to avoid would be tying the studio wooden frame to the metal frame of the shed? If so, how concerned should I be with the proposed alternative approach which has the office space tied to the the shed frame, and then the studio hanging off the office space. Would there be significant sound transmission from the studio walls to office wall and onto shed walls?

Paulus87 wrote:

Hope that helps for now? - all that's really missing from your plan now is a HVAC plan and a treatment plan.

Yep, HVAC and electrical are in the back of my mind - I wanted to sort out basic layout before thinking about these details too much. In regards to treatment, I was thinking this would be an afterthought. i.e. build the studio, test the frequency response and treat as required. Is that a bad idea and is there anything worth thinking about at this early stage?

Paulus87 wrote:

Oh, and I hate to tell you this but I highly suspect it will cost a lot more than your estimate.

I suspect you are right. That won't stop the project, but may elongate timelines a bit..... Thanks again Duncan

donkey wrote:

It's pretty well sealed and insulated, but that makes me think I probably do need some form of ventilation. I'm thinking just vents (not active/forced ventilation) would be enough?

If the shed roof is properly insulated to the point where you have a warm roof design instead of a cold roof design then there is no need for structural attic ventilation. If you're not sure then you need to check with someone local that can have a look and tell you if you need roof vents or not. The purpose of these vents is not to provide fresh air for you to breathe, but it's to stop interstitial condensation forming on the bottom of your roof deck causing mould and raining down on your room below. Typical roof vent systems are soffit vents all the way along the eaves and then a ridge vent all the way along the top. If you do need this type of venting then let us know so we can tell you how to do it without trashing the isolation of your outer leaf. If you have a warm roof design then it means you do not need any vents since interstitial condensation cannot form due to the roof deck being insulated sufficiently.

I assume the key thing to avoid would be tying the studio wooden frame to the metal frame of the shed? If so, how concerned should I be with the proposed alternative approach which has the office space tied to the the shed frame, and then the studio hanging off the office space. Would there be significant sound transmission from the studio walls to office wall and onto shed walls?

Your studio space needs to be completely unattached to the rest of the shed, so yes, you should not attach your studio to the office if the office is attached to the shed in anyway other than the floor. It's simple to avoid though, so don't know why you would be proposing to do it that way? All you would need to do is build another wall and install another door if you wanted access directly between the office and the studio. You must make sure that the studio ceiling joists do not hang from the shed in anyway also, so the ceiling joists will rest on the studio wall top plates. If for code compliant reasons you must use wall ties between the shed walls and the new studio walls then you can get ones with special resilient isolators which will maintain your isolation but still pass code. But if they're not needed then it's better without them.

Yep, HVAC and electrical are in the back of my mind - I wanted to sort out basic layout before thinking about these details too much. In regards to treatment, I was thinking this would be an afterthought. i.e. build the studio, test the frequency response and treat as required. Is that a bad idea and is there anything worth thinking about at this early stage?

Well, yes. Silencer boxes and duct work take up a lot of space. Luckily for you you'll be able to install the outer leaf silencer boxes on the outside of the studio very easily since you have a lot of space. If you plan it well you'll even avoid the need for ductwork inside the studio, but I would plan it all now before you start building the studio so that you don't overlook something. You should also make sure that you leave ample space inside your studio for appropriate treatment. Porous bass trapping and broadband trapping take up a lot of space, 3' on the rear wall and ceiling for example is not overkill. So just make sure you'll have enough space to move around and install all the equipment etc once all the treatment is in. Paul

Paulus87 wrote:

If the shed roof is properly insulated to the point where you have a warm roof design instead of a cold roof design then there is no need for structural attic ventilation.

Yep ok - I've not heard it called a warm roof before, but that's what i've got. There's anti-condensation blanket (foil lined fibreglass) across the whole roof and on all walls.

Paulus87 wrote:

Your studio space needs to be completely unattached to the rest of the shed, so yes, you should not attach your studio to the office if the office is attached to the shed in anyway other than the floor. It's simple to avoid though, so don't know why you would be proposing to do it that way? All you would need to do is build another wall and install another door if you wanted access directly between the office and the studio.

I'd like to keep it kind of close to the office as I'd like the option of putting recording/studio equipment in the office (e.g. loud computers etc.) but I take your point about ensuring they are detached. I'm going to go back to the drawing board a bit and see if I can optimise placement (i.e. within the shed, and relative to the office space) and also see if the size can grow a bit. The shed does still need to operate as a shed though and needs to house a tractor and various other equipment. One other quick question. Am I fine to exchange drywall for MDF in some areas? Ignoring the extra labour involved in cutting etc. I think density is close to the fire rated drywall. Thanks Duncan

You are in great hands there Duncan so I will offer some obtuse considerations. Different parts of the world... different names and terms. Isn't all Plasterboard used near humans Fire Rated? Most companies offer 'Acoustic' versions at higher cost, but over the while I see that many such as Rod Gervais advise using the standard stuff, but doubled or tripled. Having said that I recently noticed I think a Knauf board with an Rw of 40dB. As we are talking mass, would there be a point in using bricks for at least one wall? IMO unless you need Legal standards, the traditional Sound Level Meter is gone dinosaur. You can get a fully capable tool, including the previously exotic and expensive Leq for nada...... https://www.cdc.gov/niosh/topics/noise/app.html

donkey wrote:

Paulus87 wrote:

If the shed roof is properly insulated to the point where you have a warm roof design instead of a cold roof design then there is no need for structural attic ventilation.

Yep ok - I've not heard it called a warm roof before, but that's what i've got. There's anti-condensation blanket (foil lined fibreglass) across the whole roof and on all walls.

Paulus87 wrote:

Your studio space needs to be completely unattached to the rest of the shed, so yes, you should not attach your studio to the office if the office is attached to the shed in anyway other than the floor. It's simple to avoid though, so don't know why you would be proposing to do it that way? All you would need to do is build another wall and install another door if you wanted access directly between the office and the studio.

I'd like to keep it kind of close to the office as I'd like the option of putting recording/studio equipment in the office (e.g. loud computers etc.) but I take your point about ensuring they are detached. I'm going to go back to the drawing board a bit and see if I can optimise placement (i.e. within the shed, and relative to the office space) and also see if the size can grow a bit. The shed does still need to operate as a shed though and needs to house a tractor and various other equipment. One other quick question. Am I fine to exchange drywall for MDF in some areas? Ignoring the extra labour involved in cutting etc. I think density is close to the fire rated drywall. Thanks Duncan

Having a warm roof makes life so much easier, I'm very jealous of your "shed" which I would call a warehouse here in the UK :D Yes, you can use MDF in parts if you want... although I'd recommend keeping the construction of all the walls and ceiling identical. If you do need to use MDF on one side, then mirror it on the opposite side, this is because MDF and drywall have slightly different properties and resonances, and we want to try to keep things symmetrical. What is the reason for needing to use MDF? MDF is an excellent mass but is much more expensive than drywall. In any case, all that really matters is that you match the surface density between all the walls and ceilings. Regarding your office being attached etc... you can use this to your advantage. Build your inner leaf to include the office, and your outer leaf all the way around. Then put up a partition wall up, connected only to the inner leaf, and put a door in it, ideally in the middle of the wall and you should locate the office at the rear of your studio. Now your office will act like a giant bass trap, as well as a machine room, and of course an office. If you need to access the office from the shed area as well then just put in two doors, one on the outer leaf and one on the inner leaf. The partition wall should be very thin, either a fabric wall with insulation with/without slats, or it can be a thin drywall wall perhaps with some rack mounts for gear, the openings for the rack cabinets will allow all the low end frequencies to enter into the bass trap office. Have a look at avatar studios for an idea of how this could look, as that's exactly what they did. Paul

Hi Donkey, I'm thinking of doing the same thing with a steel building, so thanks for the work! Very helpful. I'm still not getting much input about a one-room studio except a tiny bit on the web. There certainly are a lot of them, so maybe people just go ahead with trial and error. One thing I'd love to do with this Quonset Hut is to keep something close to the curve of the ceiling, but I think that may be entirely too expensive. In any case, looking forward to reading about your progress! All the best.... BTW, here's my post on this idea: viewtopic.php?f=1&t=21195&start=15

@Aaberg, concave curves are usually bad news .

Thanks, Dan Dan. (my favorite style of Asian noodles by the way.) Yes, I hear that in this forum often. Not doubting your word, just would like to see the science backing it up. And intriguing that you say "usually". When is a dome not a dome, or when might they sound okay. Domes surely LOOK nice!