John Sayers' Recording Studio Design Forum Archive

I'm about to fulfill a long standing dream of building a studio. I've done a huge amount of research into acoustic construction over the last couple of years, primarily in this forum and via a number of books. Despite all this research, I'm still quite a bit unsure of some aspects of building construction techniques. Hopefully you can help me fill the gaps in my knowledge.

Progress
My proposed studio is still in the concept phase. I've found a designer / builder and we have started initial design discussions. The studio will be an extension on my house.

Dimensions
It will be a single multi-purpose room with internal dimensions of approximately 4.8m / 6.6m / 3.0m (W / L / H). It will be built over a garage, so it’s up one level and accessed from inside my existing residence.

Budget
Up to $150,000.

Purpose of the studio
I am a professional composer. 95% of the time the studio will be used just by myself as a quiet space to compose and mix my own music productions. 5% of the time I'll use it to record instruments and vocal performances.

I mostly compose relaxation music, so I don’t make a lot of noise. This studio is needed to minimize external noises, thereby giving me an enjoyable space to work in, and when needed, a space to record the odd voiceover, flute performance, Tibetan singing bowls, etc. The studio extension must be built at the front of my house, facing the road. At the closest point to the road, it will be about 12m away from cars (the main source of noise) as they traverse my suburban street about 30 times per hour on an average day. I’ve measured that noise at a distance of 12m at around 80db.

To maximize isolation, we will be building a room within a room. Unless otherwise instructed (and we are very open to advice at this point), we expect the build to be primarily timber + plasterboard (no brick or concrete) and will employ building techniques that are common to studios, for example, walls will have 2 completely separate frames, both with plenty of insulation, a nice deep space between them, 2 layers of 5/8 inch plasterboard either side with Green Glue between them.

My questions:

1. One thing I am still unclear on is how the walls / floor / ceiling intersect in a room within a room structure. For example, I presume that the frames for both the inner and outer walls support the outer leaf of the roof structure. Doesn’t this create a flanking path for vibration to travel from the roof directly into the inner wall? And what happens where the walls meet the floor? Can you help clear this up for me or point me to any diagrams?

2. In reading this forum's guidelines I learned that floating the floor is not really an option as this is an upper level build (or did that advice only apply to revisions to existing structures?) . So what’s the best way for me to ensure that I get the same level of isolation with the floor as I do the walls?

3. I feel a bit naïve when it comes to the outer surface structure of the walls, ceiling and floor. Whenever I see pictures of wall structures (like the myriad I've seen at http://www.usgdesignstudio.com for example) they usually specify plasterboard on both sides of the wall. Is this really how you would build an external wall (rather than a wall between rooms)? For some reason it just seems odd to me to use plasterboard on the outside of the building, even if it will be covered with cladding of some sort.

4. The biggest difficulty so far has been trying to estimate how much acoustic isolation I’ll get in the real world. Where best to spend money to improve isolation, and when do “diminishing returns” mean that I’d be better off saving some money and compromising on a few extra db? I realize that’s a big open ended question.

I have made 2 assumptions. Do these seem correct to you?

1. It’s quite possible that I’ll still be able to hear some low frequency noise from passing cars regardless of how I build this studio. 80db is a fair bit to isolate.

2. Building with 2 leaves of plasterboard and timber will not yield the same level of isolation (especially at lower frequencies) as a similar structure that uses 6+ inch concrete walls on the outer leaves. I mean, 2 sheets of plasterboard can’t compete with 6 inches of concrete, right?

I can’t think what else to ask at this point but I’m sure more questions will arise and I’m open to any suggestions. Thanking you in advance for your advice.

Hi there "chrispire", and Welcome!

I've found a designer / builder

When you say "designer", do you mean a studio designer, or an ordinary architect? I ask, because a studio designer would be able to answer all your questions, but an architect likely would not. It's generally better to have an experienced designer do the acoustic design work, and a local architect to then take that design and put into plans in the format needed for presentation to your local authorities.

It will be built over a garage, so it’s up one level and accessed from inside my existing residence.

How will it be accessed? Through a door at the same level, that leads into the house? Or via stairs that come up from below, or down from above?

I’ve measured that noise at a distance of 12m at around 80db.

That's fairly loud: I imagine that the traffic is moving quite fast? What's the speed limit on that road? Also, are most of the vehicles cars, or do you also get buses, trucks and other heavy vehicles coming past regularly?

To maximize isolation, we will be building a room within a room. Unless otherwise instructed (and we are very open to advice at this point), we expect the build to be primarily timber + plasterboard (no brick or concrete) and will employ building techniques that are common to studios, for example, walls will have 2 completely separate frames, both with plenty of insulation, a nice deep space between them, 2 layers of 5/8 inch plasterboard either side with Green Glue between them.

It sounds like you have the right basic idea, with some caveats... (see below)

For example, I presume that the frames for both the inner and outer walls support the outer leaf of the roof structure.

No. The inner-leaf ceiling is supported ONLY on the inner leaf walls. There is no mechanical connection at all between the inner-leaf and outer leaf. The outer-leaf is the actual structure of your house, and the inner-leaf is what you build inside that, but with no physical connection between them (except the floor).

Doesn’t this create a flanking path for vibration to travel from the roof directly into the inner wall?

Yes. It would create a flanking path if you did it like that, which is why you don't do it like that!

And what happens where the walls meet the floor?

The inner-leaf walls rest on the floor, and are normally nailed, screwed or bolted to it. It is possible to improve isolation by "floating" the wall on some type of resilient isolation pad, but that isn't so easy to accomplish.

2. In reading this forum's guidelines I learned that floating the floor is not really an option as this is an upper level build (or did that advice only apply to revisions to existing structures?) .

You can still float on an upper level if you really want to, but the point of the "warning" against floating is to point out that it isn't easy to do, is expensive, adds a huge amount of weight to the structure, and usually isn't needed. I'm not sure if you also read this thread:

http://www.johnlsayers.com/phpBB2/viewt ... f=2&t=8173

That explains it fairly well.

And that's the reason why it's generally preferable to build studios on the ground floor: building on an upper level makes it much harder to isolate the studio to a high level. If your studio is sitting on a concrete "slab on grade" base, then you automatically get pretty good isolation from that, since the earth below acts as both mass and damper on your slab. But when your room is upstairs, that floor is more or less like a drum head: it is a membrane stretched across a frame, with no damping. So it resonates, and easily transmits vibrations into the rest of the building.

There are alternatives to actually floating your floor properly, but they won't give the same level of isolation. For example, you could hang the joists for that room on isolation hangers, specify that they must be oversized joists, mount them lower than normal, and put several layers of mass on them for your sub floor. That would basically isolate your entire room, but you'd need some engineering help to do all the calculations, in order to specify the right type of isolation hangers for that load.

they usually specify plasterboard on both sides of the wall. Is this really how you would build an external wall (rather than a wall between rooms)?

No, that's not the normal way of doing it, for exterior walls.

In most houses these days, the exterior wall of the house is OSB covered with some form of siding. If that is how your house is built, then that's your outer leaf. If you have the option to choose, as you seem to do since it is a new build, you can specify thicker sheathing (OSB), more layers of it, or higher density materials. Or any combination of those.

For example, if you need high isolation, then you could specify that your outer leaf will be built from one layer of 3/4" OSB, plus a layer of fiber-cement backer board, plus stucco on the outside, painted whatever color you like. That would give you a good amount of mass, and a good seal. However, since this is an existing house, you'll probably want to make the addition look the same as the rest of the house on the outside, so that might not be an option.

Another option for existing exterior walls that can't be changed, is to "beef up the mass" from the inside, between the studs, before building the inner-leaf. There's a technique for that, and it can add substantial mass to your existing walls.

4. The biggest difficulty so far has been trying to estimate how much acoustic isolation I’ll get in the real world.

It's normally better to approach this from the other direction: First define how much isolation you need (in terms of decibels), then look at the various types of wall structure that will get you that amount of isolation, and choose the one you like most, and best fits your budget.

Where best to spend money to improve isolation,

That part is easy! : sealing, decoupling, and mass. If there's one single thing that kills isolation in an otherwise good wall, it is lack of air-tight sealing. Even a tiny crack under the wall, oar around a door, or through an electrical box, can cost you a huge amount of isolation. Paying attention to very, very careful sealing of everything, one part at a time, is the best single way I now of to ensure good isolation. That includes multiple seals around doors, and careful sealing around HVAC entry points.

Second on the least is decoupling, meaning to take very great care in ensuring that no part of the inner leaf touches any part of the outer leaf at all. Not even a single nail, screw or wire.

And third on the list is mass, or rather "mass continuity", in the sense that every part of the room must have roughly the same surface density, all around. So if you determine that, in order to reach your isolation goal, you need a surface density of 24kg/m2 on each leaf and a gap of of 15 cm between them, then it is critical that you ensure each square meter of wall, floor, ceiling, window nad door really does weigh at least 24 kg, and that the gap between inner and outer leaf is never less than 15cm at any point. (Those are just examples: your figures might be different).

So as long as you pay close attention to those three, you will get good isolation.

and when do “diminishing returns” mean that I’d be better off saving some money and compromising on a few extra db?

That point of "diminishing returns" is a decision that you have to make, based on your needs and your budget. It's important to realize that isolation is measured in decibels, and decibels is a logarithmic scale, so the further up you go, the harder (and more expensive) it is to get the next decibel. In a typical small room, increasing isolation from 20 dB to 30 dB is a piece of cake, and will cost a few hundred dollars. Increasing it from 50 dB to 60 dB is quite a bit harder, and will cost many thousands of dollars, and increasing it from 90 dB to 100 dB is damn near impossible, and will cost millions of dollars. In each case the step is only ten decibels, but the exponential nature of the scale makes costs soar as you go up higher.

In more simple terms: to increase isolation from 20 dB to 30 dB means that you need to block ten times more energy, while increasing from 20 dB to 60 dB means that you need to block ten THOUSAND times more energy...

1. It’s quite possible that I’ll still be able to hear some low frequency noise from passing cars regardless of how I build this studio. 80db is a fair bit to isolate.

That was the reason for the question about the type of traffic. Typical passenger cars don't put out a lot of low frequency energy, but heavy trucks and buses do. They can also cause vibration in the ground itself, which would be a really bad situation. So if you only get mostly cars all day every day at a roughly constant speed, then a decent isolation plan should very likely block all of that noise, but if you have a continuous stream of heavy trucks going by all the time, and/or the road is uneven (cracked, potholes, speed bumps, etc.), then it would be a lot harder to block that, and some of it might well be audible, even with a good isolation system.

2. Building with 2 leaves of plasterboard and timber will not yield the same level of isolation (especially at lower frequencies) as a similar structure that uses 6+ inch concrete walls on the outer leaves.

Surprising, that is not necessarily true! It is possible to get high levels of isolation from a well designed and well built drywall (plasterboard) structure. Of course, if one leaf is concrete, that certainly does make it a lot easier to get good results, but a pair of drywall leaves, built well with the correct techniques and materials, can get you very decent isolation.

I mean, 2 sheets of plasterboard can’t compete with 6 inches of concrete, right?

For a single leaf wall, there's actually not a spectacular difference. Two sheets of thick drywall done right as a single leaf, with Green Glue in between, will get you about 35 dB of isolation, and six inches of concrete will get you about 48 dB of isolation. Yes, that's a worthwhile jump, but probably not as big as what you expected.

But that's for single-leaf (mass law). For a two-leaf wall, it does make sense to have one of the leaves made from concrete or brick, as the effect is multiplied.

- Stuart -

Double post - deleted

Thank you very much for answering my questions Stuart. You've cleared up a lot for me. I think there's only one or two questions remaining for now...

Soundman2020 wrote:When you say "designer", do you mean a studio designer, or an ordinary architect? I ask, because a studio designer would be able to answer all your questions, but an architect likely would not. It's generally better to have an experienced designer do the acoustic design work, and a local architect to then take that design and put into plans in the format needed for presentation to your local authorities.

No I don't have a studio designer. The builder I'm working with is a qualified architect. I also have the wonderful support of my brother in law, who manages a large architectural firm in Melbourne. He has an acoustic consultant on staff who is available to assess our plans.

I'll probably be selling this house in less than 5 years time, so the studio itself will be a fairly straightforward room that would eventually be advertised as a rumpus or home theater at the time of sale.

Soundman2020 wrote:How will it be accessed? Through a door at the same level, that leads into the house? Or via stairs that come up from below, or down from above?

It will be accessed from within the house itself. The entire house is up on stilts on a slightly sloping block (see frontage image below). There will be no doors that lead from the outside world directly into the studio. When you enter the foyer of my house, there will be a double door on your right which opens into the studio. The existing house will therefore help to reduce sound levels that approach the entrance to the studio.

I’ve measured that noise at a distance of 12m at around 80db.

Soundman2020 wrote:That's fairly loud: I imagine that the traffic is moving quite fast? What's the speed limit on that road? Also, are most of the vehicles cars, or do you also get buses, trucks and other heavy vehicles coming past regularly?

I must admit that this figure was probably the maximum level reached during testing. It's a 50 kph back street and very few heavy vehicles pass through. That 80db figure was probably a Harley. Most of the traffic is quieter than that, so 70db cars with 60db sound reduction in the studio would be a whisper quiet result that I'd be happy with. I realize that some amount of compromise will be necessary. If a truck does come thundering down my street, some sound might be noticeable, but I wouldn't want to over engineer and over spend for something that might only happen once or twice per day. Same thing happens when my neighbor fires up his lawn mower once per week. That thing's got to crank out 90db easy.

For example, I presume that the frames for both the inner and outer walls support the outer leaf of the roof structure.

Soundman2020 wrote:No. The inner-leaf ceiling is supported ONLY on the inner leaf walls. There is no mechanical connection at all between the inner-leaf and outer leaf. The outer-leaf is the actual structure of your house, and the inner-leaf is what you build inside that, but with no physical connection between them (except the floor).

Got it. But now I'm wondering what holds up the outer-leaf of the ceiling. Are their two rows of staggered joists, one for the outer-leaf and another set attached to the walls to support the inner-leaf? I feel like I'm having a brain spasm and not understanding something really obvious here! For some reason I can't seem to visualize this, or when I do, the whole roof/ceiling assembly is over 2 feet thick.

2. In reading this forum's guidelines I learned that floating the floor is not really an option as this is an upper level build (or did that advice only apply to revisions to existing structures?) .

Soundman2020 wrote:You can still float on an upper level if you really want to, but the point of the "warning" against floating is to point out that it isn't easy to do, is expensive, adds a huge amount of weight to the structure, and usually isn't needed. I'm not sure if you also read this thread:

http://www.johnlsayers.com/phpBB2/viewt ... f=2&t=8173

That explains it fairly well.

Yes I'd read that. All makes good sense. Unfortunately I have to build this on an upper level so I'm just going to have to figure out how best to match the performance of the floor with the rest of the structure.

they usually specify plasterboard on both sides of the wall. Is this really how you would build an external wall (rather than a wall between rooms)?

Soundman2020 wrote:In most houses these days, the exterior wall of the house is OSB covered with some form of siding. If that is how your house is built, then that's your outer leaf. If you have the option to choose, as you seem to do since it is a new build, you can specify thicker sheathing (OSB), more layers of it, or higher density materials. Or any combination of those.

For example, if you need high isolation, then you could specify that your outer leaf will be built from one layer of 3/4" OSB, plus a layer of fiber-cement backer board, plus stucco on the outside, painted whatever color you like. That would give you a good amount of mass, and a good seal. However, since this is an existing house, you'll probably want to make the addition look the same as the rest of the house on the outside, so that might not be an option.

So simple. Yes that clears things up nicely. I could easily specify 2 layers of 3/4 inch OSB on the outer leaf for example. The OSB would then be clad to match the rest of my house (and of course, I'd have to ensure that the attachment of cladding does not result in penetrations that weaken its performance).

4. The biggest difficulty so far has been trying to estimate how much acoustic isolation I’ll get in the real world.

Soundman2020 wrote:It's normally better to approach this from the other direction: First define how much isolation you need (in terms of decibels), then look at the various types of wall structure that will get you that amount of isolation, and choose the one you like most, and best fits your budget.

Your advice echoes the what my brother in law advised when I started this project, and is well taken.

Soundman2020 wrote:Typical passenger cars don't put out a lot of low frequency energy, but heavy trucks and buses do. They can also cause vibration in the ground itself, which would be a really bad situation. So if you only get mostly cars all day every day at a roughly constant speed, then a decent isolation plan should very likely block all of that noise, but if you have a continuous stream of heavy trucks going by all the time, and/or the road is uneven (cracked, potholes, speed bumps, etc.), then it would be a lot harder to block that, and some of it might well be audible, even with a good isolation system.

Good to know.

2. Building with 2 leaves of plasterboard and timber will not yield the same level of isolation (especially at lower frequencies) as a similar structure that uses 6+ inch concrete walls on the outer leaves.

Soundman2020 wrote:Surprising, that is not necessarily true! It is possible to get high levels of isolation from a well designed and well built drywall (plasterboard) structure. Of course, if one leaf is concrete, that certainly does make it a lot easier to get good results, but a pair of drywall leaves, built well with the correct techniques and materials, can get you very decent isolation.

Great news.

I mean, 2 sheets of plasterboard can’t compete with 6 inches of concrete, right?

Soundman2020 wrote:For a single leaf wall, there's actually not a spectacular difference. Two sheets of thick drywall done right as a single leaf, with Green Glue in between, will get you about 35 dB of isolation, and six inches of concrete will get you about 48 dB of isolation. Yes, that's a worthwhile jump, but probably not as big as what you expected.

An extra 10-15 db from concrete was about what I expected. That's a nice juicy leap in performance, but when I take into account my actual needs, I can see that a non-concrete structure will actually meet those needs. I'm sure I'll save tens of thousands in structural engineering, materials and labour costs by sticking with good ol' wood and plaster assembled with all the appropriate acoustic construction principles in mind.

Thanks again for your invaluable help Stuart.

chrispire wrote:Got it. But now I'm wondering what holds up the outer-leaf of the ceiling. Are their two rows of staggered joists, one for the outer-leaf and another set attached to the walls to support the inner-leaf? I feel like I'm having a brain spasm and not understanding something really obvious here! For some reason I can't seem to visualize this, or when I do, the whole roof/ceiling assembly is over 2 feet thick.

Walk in to any room in your house. Look at the ceiling. That's the outer leaf, leaf number one. It's being held up by your roof trusses or beams. Then imagine building another box inside this room with none of the walls or ceiling frames touching the existing walls and ceiling. Put plaster on this new box and that's leaf number two.

Now, that's a little bit over-simplified in the context of building a new studio, and also not how you would go about it for maximum isolation (for various reasons that I won't confuse you with) but hopefully that helps you visualize the concept.

chrispire wrote:An extra 10-15 db from concrete was about what I expected. That's a nice juicy leap in performance, but when I take into account my actual needs, I can see that a non-concrete structure will actually meet those needs. I'm sure I'll save tens of thousands in structural engineering, materials and labour costs by sticking with good ol' wood and plaster assembled with all the appropriate acoustic construction principles in mind.

I think you'll get where you need to get with timber and plasterboard as well. The fact that you've started out with a realistic budget means that you'll be able to pay attention to the level of detail that's required to get the best performance out of those materials. I'd also say that Green Glue will be a real benefit to you in this build. I've used it and I can tell you it does what it says on the box as long as it's installed as specified.

all the best,

Steve

stevev wrote:Walk in to any room in your house. Look at the ceiling. That's the outer leaf, leaf number one. It's being held up by your roof trusses or beams. Then imagine building another box inside this room with none of the walls or ceiling frames touching the existing walls and ceiling. Put plaster on this new box and that's leaf number two.

Now, that's a little bit over-simplified in the context of building a new studio, and also not how you would go about it for maximum isolation (for various reasons that I won't confuse you with) but hopefully that helps you visualize the concept.

Yes - that's basically how I imagined it. The studio will have a flat roof with joists/beams holding up the outer leaf, and a separate structure of joists (attached to the inner walls) holding the inner leaf of the ceiling. I imagine that the overall thickness from the outside of the outer leaf to the inside of the inner leaf (in other words, the total thickness of the decoupled roof to ceiling structure) will end up being around 2 feet. For some strange reason I had trouble wrapping my head around this.

stevev wrote:I think you'll get where you need to get with timber and plasterboard as well. The fact that you've started out with a realistic budget means that you'll be able to pay attention to the level of detail that's required to get the best performance out of those materials. I'd also say that Green Glue will be a real benefit to you in this build. I've used it and I can tell you it does what it says on the box as long as it's installed as specified.

I was planning on using Green Glue in this build so I appreciate your recommendation. I wonder if it's worth using it in the outer leaf (between 2 layers of OSB) as well as on the inside (between two layers of sheetrock)?

chrispire wrote:No I don't have a studio designer. The builder I'm working with is a qualified architect. I also have the wonderful support of my brother in law, who manages a large architectural firm in Melbourne. He has an acoustic consultant on staff who is available to assess our plans.

Just to clarify one thing guys. Even though I have some good people to turn to for help, the moderators and contributors in this forum are still my most trusted advisers.

Though my brother in law is a talented architect, he tends to think in terms of large scale commercial construction and he doesn't have any experience with recording studios. As I'm sure you would agree, there are nuances to studio construction that only those with first hand experience can properly understand and translate to others.

In other words, thank you for your experienced advice.

chrispire wrote:I was planning on using Green Glue in this build so I appreciate your recommendation. I wonder if it's worth using it in the outer leaf (between 2 layers of OSB) as well as on the inside (between two layers of sheetrock)?

I'd say yes. but.....you have to pay a lot of attention to how your outer shell is built for the GG to be effective.

cheers,

steve

Quick progress report and a question.

I've already fired the original designer / builder I chose to work with. Unreliable...say no more. I'm now working with an architect to get plans laid down. We've had one minor win - we won't need planning permission to build this studio, so we wont have to worry about neighbors objecting and getting council approvals etc etc.

So - this 5m x 7m studio space will proceed, built as the first floor over a new garage. And if I didn't mention it before, no there is no other way to do this on my property. I'd love to build on a slab at ground level, but it's just not possible. As a result, the floor continues to be a weak point in the acoustic design of the structure. I just don't know how to build it so that it matches the acoustic performance of the walls and ceiling which will be built as a proper room within a room (2 layers of 19mm OSB or Ply, 90m framing, with insulation, 100mm airspace, another 90mm timber framing with insulation, 19mm OSB or Ply + 16m Fyrcheck plasterboard).

So how to build this floor?

If I lay an elevated concrete slab, I'll go over budget (estimates came in at well over $30,000 for that). So I'm stuck with good ol' timber.

Every article I read in this forum about floating floors leads back to this article http://www.johnlsayers.com/phpBB2/viewtopic.php?t=8173 which steers me away from floating floors (Though I note that this article refers primarily to studios built on a concrete slab).

I've read good things about Rod's pseudo floating floor - where you float the inner layer of the floor (say, 2 layers of 19mm ply) on a sandwich of 50kg/m3 rockwool (like Bradford Ultratel) but my inexperience with this approach gives me the willies. I did the math on how much weight the rigid insulation can support and got positive results, but I'll be putting a 300kg upright piano near a wall in this studio, and I can just imagine the floor compressing in that spot and peeling away from the skirting boards. Am I just being paranoid? I've never worked with this material.

I could just build a super beefy timber floor - 8 layers of ply for example - but I know that multiplying mass is never as effective as proper decoupling unless one goes to ridiculous extremes.

I've reached a point of total brain fry on this aspect of the build. I've researched myself silly. If you could help me figure out what are the best construction techniques and products to help me match the performance of the floors to the rest of the structure I'd be very grateful.

chrispire wrote:So - this 5m x 7m studio space will proceed, built as the first floor over a new garage.

Just so we're on the same page here.....the photo a few posts back of the front of the house will have a new garage built with the studio over the top, and this will be above the driveway we can see in the photo?

or are you 'renovating' part of the existing house to use as a studio?

The reason I ask is that if you're building a completely new structure you might be able to decouple the inner studio floor from the outer shell (with some serious engineering) to help you with isolation.

all the best,

Steve

Hi Steve!

I am building a completely new structure. The garage you can see will move 7m forward down the driveway. The old garage will be used for storage / home gym. The studio will go on top of the new garage. This driveway space is the only space on my property where I have room to build anything.

(P.S. I contemplated using the old garage as a studio but it's 6 x 6 with a low ceiling).

Cheers,
Chris

well, given that it's a new build you might be able to do something like this....
...now that's a very, very, VERY oversimplifed drawing of what would need to be done to achieve an end result of this concept. But perhaps it's worth thinking about as an idea. I haven't seen any threads that have an idea like this for a second story build, but second story builds are usually in existing structures, not new builds.

As far as I can see, that would give you maximum isolation for your floor and outer shell on a second story build. It's certainly not a straight forward construction, but hey, I like to start at the top and work my way down to what's actually feasible in the real world

all the best,

Steve

this 5m x 7m studio space ... If I lay an elevated concrete slab, I'll go over budget (estimates came in at well over $30,000 for that

Say what? Sounds like somebody wants to take you for a ride! From what I can see, concrete in Australia costs around $250 per cubic meter, delivered on-site. A 5x7 slab, 10cm thick is about 3.5 m3, so there's less than $ 1,000 of actual concrete in there. Maybe a bit more, if you plan to cast beams in at the same time. Allow another grand or so for rebar and mesh, and double it again for form-work, jack rental, etc.: call it 4 k in materials. Add another (large) chunk for labor... But even then, there's no way that slab can cost more than about 8 grand or so, tops, even with extravagant labor costs... There's something else going on in that quote: seems way too much to just be a simple slab floor. I'd ask for a detailed breakdown of that quote, to see what else they are hiding in there.

I've already fired the original designer / builder I chose to work with. Unreliable...say no more. I'm now working with an architect to get plans laid down

Careful on that.... The architect should take what the studio designer gives him, and use that to draw up the plans. They need to work together to make it fit local regs. If the architect takes lead here, you'll likely end up with something that looks nice, but isn't so good acoustically.

I've reached a point of total brain fry on this aspect of the build. I've researched myself silly. If you could help me figure out what are the best construction techniques and products to help me match the performance of the floors to the rest of the structure I'd be very grateful.

It might not be as bad as it seems, since there's an issue that you are missing here: The down-stairs room is a garage, not a living space, so there's no need for huge isolation going down through that floor. It can be noisy down there: I'm sure your cars won't mind too much! So as long as the actual garage area walls / windows / doors are reasonably decent in isolating and can still keep the sound in, then the upper story floor doesn't need to be built to extreme specs. You can probably relax your isolation specs for that floor a bit.

...now that's a very, very, VERY oversimplifed drawing of what would need to be done to achieve an end result of this concept. But perhaps it's worth thinking about as an idea.

Looks about right to me! Of course, with the caveats you mentioned: over-simplified, structural, etc. But that looks like a good basic plan.


- Stuart -

stevev wrote:...now that's a very, very, VERY oversimplifed drawing of what would need to be done to achieve an end result of this concept. But perhaps it's worth thinking about as an idea. I haven't seen any threads that have an idea like this for a second story build, but second story builds are usually in existing structures, not new builds.

As far as I can see, that would give you maximum isolation for your floor and outer shell on a second story build. It's certainly not a straight forward construction, but hey, I like to start at the top and work my way down to what's actually feasible in the real world

all the best,

Steve

Hi Steve,

Thanks so much for that. I'm pretty sure I understand the rationale in this design. You've basically combined the ground and first floor together as a continuous room within a larger room.

The problem I foresee is that the garage door breaks the seal on the ground floor outer leaf in a big way. The door is reasonable thin and there are gaps all the way around the edges to allow for opening and closing. So external sound will leak in and meet with the underside of the inner leaf floor, which is a single leaf.

I'm sure that the garage door will provide a little noise rejection, but nowhere near as much as if the entire outer leaf of the structure was a closed, airtight system.

Soundman2020 wrote:

this 5m x 7m studio space ... If I lay an elevated concrete slab, I'll go over budget (estimates came in at well over $30,000 for that)

Say what? Sounds like somebody wants to take you for a ride! From what I can see, concrete in Australia costs around $250 per cubic meter, delivered on-site. A 5x7 slab, 10cm thick is about 3.5 m3, so there's less than $ 1,000 of actual concrete in there. Maybe a bit more, if you plan to cast beams in at the same time. Allow another grand or so for rebar and mesh, and double it again for form-work, jack rental, etc.: call it 4 k in materials. Add another (large) chunk for labor... But even then, there's no way that slab can cost more than about 8 grand or so, tops, even with extravagant labor costs... There's something else going on in that quote: seems way too much to just be a simple slab floor. I'd ask for a detailed breakdown of that quote, to see what else they are hiding in there.

Thank you! I will be sure to revisit this subject in greater detail with the architect.

Soundman2020 wrote:

I've reached a point of total brain fry on this aspect of the build. I've researched myself silly. If you could help me figure out what are the best construction techniques and products to help me match the performance of the floors to the rest of the structure I'd be very grateful.

It might not be as bad as it seems, since there's an issue that you are missing here: The down-stairs room is a garage, not a living space, so there's no need for huge isolation going down through that floor. It can be noisy down there: I'm sure your cars won't mind too much! So as long as the actual garage area walls / windows / doors are reasonably decent in isolating and can still keep the sound in, then the upper story floor doesn't need to be built to extreme specs. You can probably relax your isolation specs for that floor a bit.

Just to clarify, my priority is to block external noise. I mostly compose relaxation music, so I don’t make much noise at all! I will record acoustic instruments and vocal performances from time to time, but almost never will I record drums or amped guitars etc. I really just want a quiet, meditative space that will block out the majority of neighborhood sounds I mentioned earlier and allow me to record instrumental performances.

I'm pretty confident that things are on the right track and that I can achieve the isolation I want with most of the structure, it's just this elevated floor that's been bugging me. It's the main weak point as far as I can see.