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PostPosted: Sun Dec 24, 2017 7:40 am 
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Location: Boston MA USA
First, thank you all for hours, no days of reading that is making my head swim. So much good stuff here but I have yet to find an answer to my problem I think. We are in the process of building a live room studio for recording and video production on a beautiful pond in the heart of Boston MA USA in an existing garage with many challenges. The area is a densely populated and the sound carries over the water so this design has to be super tight. Plus my studio engineer is a mad drummer. :shot:

The first challenge is the existing building is a stress skin construction where the structural walls consist of one layer of 1/2" OSB / 3 1/2" of polystyrene foam / one layer of 1/2" OSB all glued together. The only lumber in the wall system is at the corners and opening. So removal of an inner wall surface is not possible since it is part of the structure. The studio will have cathedral (two different slopes) with a balconies that is current and is part of the structural integrity of the building so it can't be removed. Because of this it would be difficult to build a standard two leaf system using tilt up construction (framing a wall on the ground, sheathing it with drywall, tiling it up and sheathing the other side). My intended solution is to hang RC on the existing walls of the building, sheath that and then build a floating wall inside of that and sheath that. I would end up with.....existing building wall which is 1/2" OSB adhered to 3 1/2" polystyrene adhered to 1/2" OSB / RC / 5/8" drywall / green glue / 5/8" drywall / 2" air space / 3 1/2" isolated wood frame wall with rock wool / 5/8" drywall / Green Glue / 5/8" drywall / 3/4" shop grade plywood (finished wall surface). What do all think? Does this work as a two leaf system? Also thought about adding more layers of 5/8 to the inner wall. Usual detail on caulking top, bottom and corners with foam backer and caulking.

Second challenge is the garage doors that have to stay in place. I was just going to remove the tracks, frame a stud wall inside the doors in contact with the floor and roof system and treat framed wall the same as the building structure walls.

Third is the floor system. The garage has a 10" hollow core pre stressed concrete floor with a 2" concrete topping over a concrete basement with 9' ceiling. I know I'm creating a drum but tests so far seem to hint that it should not be a problem. If it is I can create a floor system after (ceiling height under the balcony is tight). Am I creating a short circuit? Sound traveling through the floor to the outer shell of the building?

Fourth is the ceiling. Not really problem just a question. Which is better, three layers on 5/8" on RC or hung on a floating frame attached to the roof with isolators?

Fifth is that we are trying to keep the three approx. one square meter windows looking out over the pond. Current ideas is two layers of glass, one 1" (I own this currently) and one layer of 1/2" laminated separated by a 4" to 5" air space. Additionally removable panels for heavy drumming and bass playing.

I've have built studios before but that was long ago and I didn't design the construction. Thanks for reading through and happy holidays. I'll be spending my next couple of days doing demo, prepping for construction, hopefully next week.

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PostPosted: Sun Dec 24, 2017 1:38 pm 
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Hi there "MrWaj", and Welcome to the forum! :)

Wow! You certainly do have a challenging situation to deal with. Fortunately, the same procedure that works for any studio build, will also work for yours... it will just be a bit more complex in the design stage.

So, first order of business: Put a number to your most basic need. Start with that, and the rest follows, and flows.

In other words, you need to actually measure / calculate / estimate the real number of decibels of isolation that you will need. It's fine to say " this design has to be super tight. Plus my studio engineer is a mad drummer", but there's nothing in there that you can plug into the equations for isolation, to figure out how to build your walls. You need a real number, that realistically represents the amount of isolation that you need, in decibels. So you will need a proper hand-held sound level meter (not an app on your iPhone!), and also a copy of your local municipal noise regulations. With your sound level meter ("SLM"), measure the level put out by your " mad drummer", when he's doing his best to wake the dead. That answers the first question that you need a number for: "How loud am I?". Do the measurement with your meter set to use "C" weighting and "Slow" response. Measure in several places around him, at a distance of between 1 and 2m. Note the highest level, and also the average level.

Now tell him to stop playing, send him home, and wait for the quietest time of night, then measure again with your SLM, same settings, when it's very quiet at the place where the studio will be built. That partially answers the second question: "How quiet do I need to be?". And the final double-check for that second question, is to look it up in your noise regulations, ad see what the LEGAL requirement is: The number that you cannot exceed. Compare that with your own measured second number: use the lower of the two numbers as your final answer. In other words, if you measured 35 dB with your meter for the quietest moment, but the regulations say you must stay below 40, then the number you want is 35. But if you measured 50 and the regulations say you must stay below 45, then the number you want is 45.

Ok, so now you have two numbers: the "How Loud" number, and the "How Quiet" number. Subtract. The result is the answer to the key most important question about starting your entire studio build. It answers the question "How much isolation do I need?". It puts a realistic, valid, objective number in place as the goal for your isolation.

Now you can start thinking about your design process. It was impossible to think about that before, because you did not know what your goal was, but now you do. Before, it was sort of like you deciding to go on vacation, and then you asked other people how to get there, what to do when you got there, what clothes to take, etc.... but you did not tell them where you wanted to go on your vacation! It was impossible to answer your questions, because you dd not have a goal. You just sort of imagined yourself going on vacation, and buying plane tickets, and sleeping in a hotel, renting a car, etc., and you were asking about those things, but nobody could help you, because even YOU did not know where you were going! How can you buy a plane ticket, if you don't know where you need to fly to? How can you book a hotel, if you don't know what city to book it in? How can you isolate a studio, if you don't know how much isolation you need?

With your goal number in hand, you can then look at various construction methods that are capable of achieving that goal, and compare them to what you already have, to see if it is possible to get where you want to go, with what you have on hand. It might not be. It might turn out that there is no feasible way to use what you have to achieve the isolation you want. That's a real possibility. It would be a sad outcome, but at least you would KNOW that it was not possible, and you'd have to go looking for another place.

Or it might turn out that there are a few ways to do what you want with what you have. That is also feasible. In which case, you get to choose which of them makes the most sense for you, and for your budget.

So, I can't really answer most of your questions with concrete answers, because neither you nor I know what we are trying to accomplish here. All I can offer is general comments regarding where you are, and roughly, approximately, ball-park, guesstimating, more or less, possibly where I imagine I think you might maybe be going....! :)

Firstly, I'm assuming that you need high isolation, maybe around 60 dB, based on what you mentioned about a mad drummer and sound carrying over the pond.

Secondly, I'm assuming that you have a large budget, because if you don't, I can already tell you that you can't get where you say you want to go, because of the first assumption: you can't get high isolation on a shoe-string budget.

OK, so with those tow basic assumptions, lets look at what you have:

Quote:
walls consist of one layer of 1/2" OSB / 3 1/2" of polystyrene foam / one layer of 1/2" OSB all glued together.
Not very hopeful as the basis for a building that must provide high isolation. SIP's are not much good at that. (SIP = Structural Insulated Panel). They are pretty good for thermal insulation, but not so good for acoustic isolation of loud sounds. There's a fair amount of research on this, and it' is not very heartening. For example, this is what it says in a study on using SIPs for new houses near a road: "Sound transmission loss testing of standard SIPs, however, reveals relatively low acoustical performance especially in the 630 Hz range. This characteristic acted as a band pass filter allowing a portion of broadband noise to enter the house." If there's an isolation dip way up high in the spectrum at 630 Hz, then that automatically implies that the panel is pretty lousy at acoustic isolation across the entire spectrum below about 1 kHz at least, and probably more like 2 kHz.

And in a technical bulletin about SIPs in the UK, they had this to say about the acoustic properties: "A SIP, much like timber studwork, relies on the mass and continuity of plasterboard linings to provide the majority of the sound insulation performance. If the sound insulation performance of the wall needs to be improved, the use of acoustic rated plasterboard in multiple layers is normal. An acoustic consultant would need to be involved to determine specification and performance requirements." Translation: SIPs are really lousy at isolating sound, and you need to add many layers of high mass materials to get the performance up to scratch. On a manufacture's website FAQ, they have this to say about how well SIPs work: "...low frequency sounds are not effectively stopped by a SIP building envelope.".

I think you are getting the picture: your SIP walls are not doing you an favors, and you are going to need to add some major mass to them, if you need good isolation.

Here's a real graph, showing how a SIP wall compares to a standard stud wall:

Attachment:
SIP-acosutic-properties-polystyrene-insulated-panels-OSB-TL-graph-STC.jpg


Not a very happy sight. It gets 7 points LESS isolation tha¿n an ordinary stud wall, which is already pretty poor. And do note that this test was done with a layer of drywall already applied to the SIP! Imagine what the sip would be like, all by itself....

So you are starting from a highly disadvantageous point, and you need high isolation... Take another look at my second assumption...

Quote:
My intended solution is to hang RC on the existing walls of the building, sheath that and then build a floating wall inside of that and sheath that. I would end up with.....
You would end up with a three-leaf system! :shock: And a three-leaf system will perform WORSE than the equivalent two-leaf system. If you really do want to build a 3-leaf wall, you will need to compensate for the isolation that you are losing by building 3-leaf. It would be far better to build a 2-leaf wall, which is the optimum configuration for any give isolation need (lowest cost, lowest mass, lowest thickness). I'm not saying that you can't do a 3-leaf system: you can if you want, but it will cost you more, use more materials, and more space. And since your plan has two of the leaves very close, with a very thin air gap between them, you'll need to do some rather major compensation to overcome that....

Quote:
Second challenge is the garage doors that have to stay in place. I was just going to remove the tracks, frame a stud wall inside the doors in contact with the floor and roof system and treat framed wall the same as the building structure walls.
Correct! That's the best way of dealing with they typical garage door issue, where the door has to remain physically. Fox the door permanetly in place, remove the hardware, and build a wall in front if it. Yes, it does create a three-leaf system in that part of the building, but you have no choice. And since it is a simple stud wall, it is easy to compensate.

Quote:
The garage has a 10" hollow core pre stressed concrete floor with a 2" concrete topping over a concrete basement with 9' ceiling.
What's down in the basement? Anybody down there? Could YOU go down there? That basement would likely be a better candidate for a studio that needs very high isolation. So if nobody is using it right now, I would suggest that you consider moving your studio down there.

Quote:
I know I'm creating a drum but tests so far seem to hint that it should not be a problem.
How did you test that? What numbers did you get? What is the frequency that gives you the least isolation for airborne sound transmission, how much isolation did you get at that frequency? What was the level of impact noise isolation that you measured?

Quote:
Sound traveling through the floor to the outer shell of the building?
If sound is getting into your floor, then it is ALREADY in the shell of the build, regardless of the basement. That's why the IIC test results are so important. If you can show what you got there, then that would help. A simple solution might be a drum riser and bass cab isolation pad. If not, then your only solution is a PROPERLY floated floor, and we get back to my original second assumption: you have an abundant budget. You'll need a large budget if you have to float your floor.

Quote:
Fourth is the ceiling. Not really problem just a question.
Why is the ceiling "not really a problem"? That's strange: normally, in a typical garage isolation scenario, the ceiling is a MAJOR problem. I'm wondering why you think yours will not be.

Quote:
Which is better, three layers on 5/8" on RC or hung on a floating frame attached to the roof with isolators?
When you go on vacation, which is better: The road that goes the other way, or the river that goes in a different direction? :) There's no way to answer your question, because nobody knows what your goal is, or any of the other details that would be needed to come up with a valid answer. The ONLY answer I can give you here, is that the best ceiling system for high isolation in general, is a fully decoupled two-leaf system where the total mass is split evenly between the two leaves, there is enough surface density on each leaf and enough damped air gap between them to produce an MSM resonant frequency that is at least one octave lower than the lowest frequency that must be isolated, and sufficient overall mass to satisfy the Mass Law parts of the remaining 2-leaf MSM equations. I can't be more specific than that, since there is not enough information to go on. Not even to hazard a wild guess. Another way of looking at it: the inner-leaf of the ceiling must have the same mass as the inner-leaf of the walls, the outer leaf of the ceiling (roof?) must have the same mass as the outer leaf of the walls, and the air gap in the ceiling must be at least as large as the air gap in walls, and damped to at least the same level.

Quote:
Fifth is that we are trying to keep the three approx. one square meter windows looking out over the pond
"If you like your windows, you can keep your windows"! :) On a more serious note, there's no problem with having glass in studios. Glass is very dense, rigid, and slates well... if used correctly.

Quote:
Current ideas is two layers of glass, one 1" (I own this currently) and one layer of 1/2" laminated separated by a 4" to 5" air space.
Did you do the math? Does that produce the level of isolation that you need at the frequencies where you need it?

Quote:
Additionally removable panels for heavy drumming and bass playing.
Why? How would those work? Why would you need them? I'm not sure I understand what you are trying to achieve here, or how that would work in practice. Please explain.

Quote:
prepping for construction, hopefully next week.
WHAAAA????? :?: :?: :?: :?: :shock: :shock: :shock: :roll: :roll: :roll: No. Just no. BIG no. HUGE NO! You are about a YEAR away from being able to build anything. And I'm being realistic. You don't have any plan at all, you don't know hoe much isolation you need, you don't know what construction materials you need, you don't know how to put them together, you don't have a structural plan, you don't even know what your legal requirements are, and I'm betting that you don't yet even have a building permit....

I've designed quite a few studios over the years, and I've been involved in one way or another with the construction of many, many others, both on the forum and off it. I don't want to seem harsh, or condescending, and I'm not trying to belittle you, but one thing I can grantee, without any hesitation: if you start building before you are ready, with a fully detailed plan in place, you are doomed to fail. I've seen it so many times, and it is always sad. We occasionally do get people coming on the board like this, without the slightest plan and saying they are going to start building next week, but the questions they ask reveal that they are nowhere near being ready to even THINK about starting. We always tell them the same thing: "STOP! Don't do it!". The ones who listen, generally go on to build spectacular studios. The ones who DON'T listen, think they know better, and carry on building anyway, always fail. Every. Single. Time. We know that they fail, because their threads always dry up after a short while... and you can be sure that if they DID succeed, they'd be back in our faces, rubbing our noses in their success, and showing that we were so very wrong by showing the wonderful results they got from their studios... but that has NEVER happened. Not even once. Those studios either never get finished, or they do get "finished" but turn out to be so lousy that nobody would ever consider using them.

I'm hoping that you are one of those guys who will be the first type: That you really will stop, and listen, then take the time to learn everything you need to know in order to design your place, then design it comepltely, in full details, then get the necessary red tape out the way, and only then think about starting to build.

So you have a choice here: you can start building in January 2018 and fail, or you can start building in January 2019 and succeed. If all goes well, and your needs are not too complicated, you might even be able to shave several months of that and still succeed. But if you start in January 2018, I'd bet really good money that you will not succeed at all.

Please tell me that you are the first type of studio builder: the one one who came here to listen, and learn how to do it right, and take the necessary time!

Merry Christmas!



- Stuart -


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PostPosted: Fri Feb 09, 2018 2:25 pm 
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Sorry about the delay in returning a post and thanks for the input.

First off, when a I said we are looking to start construction soon I meant setting up a new location for all the stuff in the existing building, building the accessory building that will house the office and like and make structural changes to the existing building so we can build a room in a room. Yes, we have a building permit. As long as my structural engineer signs off on the plans the local inspector could care less what we do. I do so much work in the area and the local building inspector is so overloaded that it is a rare occasion that they even inspect my job since I have a fairly good reputation.

We have done sound measurements and are looking to get something in the order of a 65 decibels of reduction. One of the reasons that I posted on this forum is that we had a professional help us do an initial design but some of the structural changes we now discovered lead us to some additional challenges. Our professional help is no longer available do to personal reasons. I have sketches of most of the assemblies (doors, windows, detailed wall to ceiling connections, HVAC, electrical, etc) that I did that were approved by him. Now I'm looking to resolve some details that have popped up.

My initial thinking was the SIP wasn't a leaf but I get it that it could be. So attaching the three layers of drywall to the building shell would end up being the outer leaf. Also looking at Quiet Rock (Easy Snap or 530) as a substitute on the ceiling since it weighs less. Still have yet to see the comparison between Quiet Rock and drywall green glue set up measured at lower frequencies. It's strictly a weight issue to help minimize structural changes to the building.

One of the biggest challenge to rear it's ugly head is one I should have seen but did not. Once the building is stripped we will have removed the second floor (basically a loft) that is effectively the collar ties of the building. Our two options were to put in a supported ridge thus eliminating the need for collar tie or replacing the clear ties with something else. The supported ridge beam is possible but it make any possibilities of a new second floor loft a no go do to the size of the beam, 18" deep, which would give us not enough headroom. The other option is to replace the collar ties with wire cables or steel rod that would tie the outside shell together at the line were the roof meets the wall. This would be an issue because the three to five collar ties would be attached the structure of the building but pass though the interior and the interior leaf thus becoming a flanking issue. Soooo, my current question is... if we were to go with the collar tie option would it be better to use 5/16" wire cable or 3/4" still rod and if the flanking issue is a big one, which i think it will be, can i wrap the cable /rod with something to isolate it. I have other ideas that I am working on with my structural engineer but a know that the cost would be quite high. Note that we do a lot of video so any isolation of these cables/rod needs to be a minimum and look good since they are in the one of fire for the videographers. Ideas???

You mentioned budget. Of course we are looking into saving money were we can but we also know to build a good sound we need to invest. Currently our minimum construction budget not including labor and low voltage electrical (sound wiring vs 110 volt) and lighting is $25000. We have more $ if needed but trying not to. Currently saving money by acquiring materials from existing studios that are shutting down, building savage yards, Craigslist and my suppliers bone yards. We will spend what it takes to make it happen.

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PostPosted: Sat Feb 10, 2018 2:15 pm 
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We have done sound measurements and are looking to get something in the order of a 65 decibels of reduction.
65 dB is a tall order, actually. The maximum that is readily achievable for most studios built on an isolated monolithic slab, using conventional construction, with a good budget, is about 70 dB. Getting more than that requires more complex techniques and materials that would be accessible to the typical studio builder.

To give you a rough idea of how hard this is, if you wanted to get 65 dB of isolation from just building an all concrete "bunker" that sits on the ground, that concrete would have to be about 50cm thick (roughly 19"). That's how much mass you need, for that level of isolation. Are you SURE you need that much? It is doable, but not the way you are planning right now.
Quote:
One of the reasons that I posted on this forum is that we had a professional help us do an initial design but some of the structural changes we now discovered lead us to some additional challenges. Our professional help is no longer available do to personal reasons.
Did this professional studio designer know that you were aiming for 65 dB Isolation? Is that what he designed it for? Or did he design it for a lesser level, and you are now trying to increase the isolation?

Quote:
Also looking at Quiet Rock (Easy Snap or 530) as a substitute on the ceiling since it weighs less.
You seem to be missing the point: You CANNOT use anything that "weighs less", because the ONLY way to get very high levels of isolation, is with mass. Mass is the key to isolation: it's the principle of physics that is behind the way isolation works. If you reduce the weight ( = mass) of ANY part of the structure, then you reduce the isolation. Period. It's that simple.

Quote:
It's strictly a weight issue to help minimize structural changes to the building.
If the structure of the building cannot support the mass that you need to attain 65 dB of isolation, then you have exactly two options: 1) Improve the structure of the building such that it can support the mass that is NEEDED for the level of isolation you ave defined, or 2) Settle for a lower level of isolation: that which can be attained within the structural limitations of the building.

Mass is the number 1, number 2, and number 3 most basic key to isolation. It's the foundation for everything. All of the equations for determining how much isolation you can get, feature the symbol "m", which stands for "mass". There is no way of getting around this: there are no magical products that provide more isolation that is allowed by the laws of physics.

Quote:
The supported ridge beam is possible but it make any possibilities of a new second floor loft a no go do to the size of the beam, 18" deep,
Unless you use a steel beam: RSJ's can support a hell of a lot of weight in a fairly compact package.

Quote:
Soooo, my current question is... if we were to go with the collar tie option would it be better to use 5/16" wire cable or 3/4" still rod ...,
You should use whatever your structural engineer says you should use! There's a HUGE difference between the strain that 5/16" wire can take and what a 3/4" steel rod can take. Asking for life-or-death advice like this on an internet forum is not a good idea. The ONLY person who can legally and correctly give you that advice, is a certified structural engineer who has physically been to your location, inspected the structure, done the calculations, and given you his professional recommendations in writing. Collar ties are a big deal: they keep the roof from collapsing in on itself. If they are not dimensioned correctly, there's a very real possibility that the roof will collapse. If that happens, the impact of the roof collapsing could also bring down the rest of the building.... Don't take any chances here: listen to your structural engineer, not an internet forum.

Quote:
and if the flanking issue is a big one, which i think it will be, can i wrap the cable /rod with something to isolate it.
For the type of extreme isolation that you are talking about, you would need to run that steel rod through something hollow and massive, such as a fairly large diameter steel pipe, arranged such that the rod is connected ONLY to the outer-leaf, and the pipe is attached ONLY to the inner leaf, and ensuring that they do not touch at any point. Stuff the pipe with insulation, and run the bar through the center of that.

There's a third option here, very seldom used these days, but still possible. Buttress the walls on the outside, to take the outwards forces that will be present if there are no collar ties. If you've ever seen photos of old cathedrals, you've seen these flying buttresses on the outside. I doubt if that's an option for you, but it might be.

One other long-shot would be to replace the entire roof with a flat roof, and build up the walls to that level.

There's not much else you can do!

- Stuart -

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PostPosted: Sat Feb 10, 2018 4:14 pm 
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65 is a tall order and that is why I'm being so careful in my design. And an architect/builder and a student of engineering I get that maintaining the structural integrity is key. And yes, buttress are on the table as part of the addition that houses the office. Unfortunately if we do that the buttress other side of the building will eat up storage space so cable or steel rod collar tie are looking to be a good option if we can solve the flank issue that they cause.

"For the type of extreme isolation that you are talking about, you would need to run that steel rod through something hollow and massive, such as a fairly large diameter steel pipe, arranged such that the rod is connected ONLY to the outer-leaf, and the pipe is attached ONLY to the inner leaf, and ensuring that they do not touch at any point. Stuff the pipe with insulation, and run the bar through the center of that."

Thank you, that was the information I was looking for. According to my engineer we have an option of using steel wire or steel rod, both being tensioned. From a sound standpoint is there a better option (the wire would be smaller diameter than the rod do to fasteners). Then how large such the the steel pipe we are running it though be? Is mass an issues for the pipe? If so, is cast iron a better option? If we have 6" between the inner and outer leaves of the system should the pipe be as long as possible? Say 5" buried in the inner leaf and framing of the system. This is were I have no idea of the proper design.

I get that mass is good but I keep reading that materials such as Quiet Rock give better performance for less mass. Is that because of the the inner layers of the material and is it the same as using a product such as Green Glue? I'm guessing that as you said, there is no magic and that it's all about mass.

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PostPosted: Wed Feb 14, 2018 9:37 am 
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So just got the word the we will have 5 1/2" tensioned galvanized cables running through the space penetrating the building structure and anchored the the outside of the structure. We can use 7/16" if there would be a big difference as far as sound transmission, it is just harder the find 7/16". What is the thought on size and weight of pipe it should run through (steel, cast,) and if the distance between the inner and outer leaf inner surfaces is 8" should it be about 7" so it just stops shy of the outer leaf or are you talking about running the pipe through the entire inner space which would certainly be a challenge...... Thinking about it, I the later is what you meant isn't it. If so can I assume the mass of the wall of the pipe should be at least the mass of the wall leaf per square foot?

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PostPosted: Thu Feb 15, 2018 7:29 am 
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One quick question. Is there any disadvantange to isolating the the inner leaf stud wall from the sub floor and then building the isolated floor system inside the room vs building the isolated floor system and then building the inner leaf system on top of the floor? We are planning on using a Mason LDS spring mounted system for both. Mason's engineer said that their spring system would work fine for this. Reason for doing this is we have different floor heights is different rooms and the ability to spec the floor system after all else is built (we could do it at a later date or not at all if it is not needed.

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PostPosted: Sun Feb 18, 2018 1:51 am 
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Quote:
One quick question. Is there any disadvantange to isolating the the inner leaf stud wall from the sub floor and then building the isolated floor system inside the room vs building the isolated floor system and then building the inner leaf system on top of the floor?
The advantage to building the walls (and ceiling) on top of the floor, is that you have a much, much greater mass that is floating, meaning that the frequency can be kept low easily, and won't change much as you load and unload the floor with people, equipment, instruments, beer, pizza.... If you float ONLY the floor, then those changes in mass can be a substantial part of the entire floated mass, but if you float the entire room then those changes are negligible.


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PostPosted: Wed Feb 21, 2018 1:31 am 
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Location: Boston MA USA
Thanks for the reply., never thought about in that way. Have to wrap my head the concept. Let me see if I understand. If I build the walls on the floor system and iIf my walls, ceiling and floors weigh in at 20,000 lbs.and I designate spring system to handle that plus or minus 25% my live load (musicians, gear,beer etc can be 5,000 lbs. before the spring "bottom out" or reach there capacity and lose isolation. If I float the floor independently and it weighs in at 5,000 lbs. and I design the spring system to handle the same plus or minus 25% then anything over 1,250 lbs. live load shorts out the isolation. If that is so then doing the numbers to make sure the live load is accounted for using a certain system should work. Again if this is true then I have to run the numbers for weight and cost and see what makes sense. Does this make sense?

Additional quick question (I'm coming up with them as I build the studio in my head) is......My outer leaf is three layers of 5/8" type-X weighting in at 7 lbs per sq ft attached to the building shell. The ceiling the underside of a sloped roof that has a 9 1/4" LVL rafter every four feet with the drywall layers in-between the rafters. The LVLs are about 4.5lbs per lineal foot. Is that enough mass or should I wrap the rafters in drywall to and mass.

_________________
"Music washes away from the soul the dust of everyday life"
Berthold Auerbach


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