Hi, first of all thank you to John and all the other contributors here for an invaluable resource. I've spent a couple months now researching and planning a new studio installation and the wealth of information here has been a huge foot up.
Please forgive the crudeness of the floor plan I have attached. The control room is on the east, the live room is on the west, and there is a small lounge on the south next to the existing bathroom.
My project is a series of compromises between the ideal and reality. My budget is limited and this all has to be done to code and the fire marshall's approval, two conflicting considerations which provide me with a narrow intersection of possibilities.
Let me be honest here: I have no intention for this to be a world-class facility. The rent is dirt cheap, the lease term is short, and if I decide to target a more upscale audio market in the future, I will move. My feeling is that this place will be a godsend for musicians who can't afford to go to a studio that's trying to carry $2000/month rent and $100k worth of gear on credit. (I worked at that studio; it sucked for everyone involved.) The beauty of this place is that our overhead is extremely low, and myself and my partner are good at what we do, which is getting things done, sounding great, within our means. If you ask me, that's the only reasonable approach to the business in 2010, but it takes all sorts.
My first plan used the geometrical sort of layout that John promotes without any real concern for sprinkler layout. The building owner explained what would be involved in order to meet fire code and basically it was beyond my means.
You will notice there is a 7'x10' grid overlaid on the floor plan. Basically this is two things: the (massive) beams of the building run north-south on the grid, and in the middle of each box formed by the grid there is a sprinkler head. The 10' north/south line is just a technical coverage rule. Any wall which interferes with the coverage from the sprinkler grid increases the cost of the build-out because the sprinkler system has to be adjusted to compensate for interrupted coverage.
So I simplified my plan to adapt to the sprinklers and stay under budget. My plan is to compensate for the less than ideal acoustic configuration with room treatment after the fact.
The ceilings are 9'. The exterior walls on the west and south of the plan are the exterior of the building: the west wall has two large plate glass "storefront" type windows, and the south wall has tall mill-style windows. The north and east walls are neighboring tenants in the building. The bathroom already exists as does the exterior door at the northwest corner.
I went with room-within a room planning mostly to cut back on street noise from the outside of the building. (We do not have to worry about bothering anyone.) The east side of the building set back about 100 feet from a moderately busy road with mostly light-vehicle traffic. The mill windows are acoustically leaky. Where the interior studio walls run against the exterior walls, the windows will be boarded off. More on this later.
Interior walls will be 2 layers of sheet rock, insulated with 3" SAFB mineral wool, 2.5 pcf. I don't plan on floating the floors.
The current floor plan shows double doors between the control room and the live room, but my latest thinking has me replacing those doors with windows (1/2" laminated glass.) Effective glass or sliding french doors are expensive as hell and the Americans With Disabilities Act rules about doors in sequence and also raised barriers in the floor (like the bottom of a sliding glass doorway) complicated things so quickly that windows became an obvious choice.
I've laid out what details I can think of- please ask me to clarify anything I've omitted.
Here are my questions:
1. How badly am I injuring myself by not floating the floors. They are 100+ year old hardwood. The building is an industrial mill building. I just now realized I should get some more info on just how the floor is constructed, but my impression was that they felt very solid, and did not make much noise underfoot. They were not finished like a nice hardwood floor would be so I didn't get the impression that they were acting as an actual acoustical leaf. Keeping in mind that I am not seeking perfection or even close to it, will my wall construction be rendered meaningless by the floor, or are their varying grades of foolishness to the choices people like me may make?
2. As to the windows between the control room and the live room: why is it that double windows like this are always shown as being joined with a cavity between? (With the need for the dessicant (sp) and all that) Why can't the two walls be completely isolated there, with just a window in each wall, as opposed to boxing them together and sealing them off together?
3. At the southwest corner of the control room, the walls surrounding the control room and the live room converge, exposing the cavity between the two walls. Originally I had extended the north wall of the bathroom west to a junction with the live room wall, boxing in the control room again. But this seemed redundant to me since I already had two walls between the control room and the exterior of the building. It also introduced the problem of another double door passageway and the ADA, etc. Where the cavity between the control room and live room walls is exposed, should I seal it off somehow, or just cover it with cloth or something? Or was my original idea right?
4. I actually have an architect looking into this next issue, but maybe someone here can point me in the right direction. The building owner and the architect both are concerned that the cavity of air between the walls will be an issue for the fire marshall, since there is no sprinkler coverage there and a fire could race through there. The architect mentioned we might need some kind of fire breaks, but all I could hear when he said that was "coupled walls." Have any of you dealt with this issue, and how do you meet fire code for these kinds of hidden cavities?
5. What would be a cost-effective way to board up and muffle these windows? I know that the building owner wants to cover them with painted plywood which visually helps conceal the fact that they are boarded up. Is there a way I can work with him on that to also decrease the sound transmission through them?
Alright, that is enough for now. I'm ready to be savaged as I know many of my compromises will be shocking to the sensibilities. My most sincere thanks in advance to any of you who have slogged through this post and might take the time to respond.
A couple of questions on a new build/planning
Originally posted at johnlsayers.com, topic 14374.
Answer: viewtopic.php?f=2&t=81731. How badly am I injuring myself by not floating the floors.
they are not joined: it just looks that way. Normally, it's just a piece of 703 wrapped in cloth that "joins" them. That is part of the acoustic damping around the window cavity, which is important. Another reason is dust: every time you open and close a door, you change the air pressure in the MSM gap, which might disturb any dust that happens to be in there. that shouldn't happen, of course, but Murphy does not agree with what "should" or "should not" happen. You don't want dust settling on the INSIDE surfaces of your windows... pretty hard to clean in there.2. As to the windows between the control room and the live room: why is it that double windows like this are always shown as being joined with a cavity between?
The walls ARE completely isolated. There is no mechanical link. It is simple acoustic absorption that you see around the windows, which damps the cavity resonance, and therefore helps improve isolation. - Stuart -Why can't the two walls be completely isolated there, with just a window in each wall,
Thanks so much! Clear as a bell. :D
Is this particular George Holmes of Connecticut in fact the drummer George Holmes?
As in the days of Lamparelli's ?
As in George Holmes Drum Studio?
No, sorry. :( I'm too young or new to the area to know the George Holmes of whom you speak.
With a building this old, the methods used to construct it were most likely what is called balloon framing. This is where the studs go from floor level to roof level with no break and that leads to an air cavity that has been know to create a "chimney" effect that allows fire to move from one level to the next with no ability by the structure to slow the fire down. There is no simple fix as all of the air cavities have to be blocked. Even installing a sprinkler will not make it compliant. With no pictures to get a visual on the area, it is difficult to say, but it reads like that "could" be the issue. Brien4. I actually have an architect looking into this next issue, but maybe someone here can point me in the right direction. The building owner and the architect both are concerned that the cavity of air between the walls will be an issue for the fire marshall, since there is no sprinkler coverage there and a fire could race through there. The architect mentioned we might need some kind of fire breaks, but all I could hear when he said that was "coupled walls." Have any of you dealt with this issue, and how do you meet fire code for these kinds of hidden cavities?
Thanks Brien, not sure if we're talking about the same thing or if I understand correctly. The cavity to which I refer is the 4" gap created by double wall studio construction. Is that what you meant? Are you saying that creating any kind of between-wall cavity could be a problem due to the nature of the building itself? I thought this was just a general fire code issue and wondered how other people dealt with it.
For example, the architect and building owner both mentioned to me that there are fire code rules which allow for some small amount of horizontal cavity to be created- for example, behind a hung tile ceiling. I'm wondering if anyone knows anything specific about dealing with these vertical between-wall cavities that these kind of designs lead to.
If in order to meet fire code I am unable to leave any open air gap whatsoever, what should I fill that space with?
George,
if I understand better exactly how you are constructing this I can provide you with a detail that does not couple the wall assemblies...... this is not a big problem.....
Do you have any actual plans yet on the construction of this space - and by this I mean a section through the walls between the control room and the tracking room?
Just FYI - this issues is going to exist at all of the walls - not just the walls separating those rooms......
Rod
Yes I know that I have to solve this issue for the air gap running between all the walls besides the control room/live room. Section through the walls from control room to live room: 2 layers of sheet rock wooden studs with 3" Thermafiber FASB 2.5 PCF insulating 4" air gap and then the second wall, starting with the insulated side and ending with 2 layers of sheetrock. I'm toying with the idea of also using resilient channel but I'm not sure if it's overkill in this situation since the wall frames are already decoupled. Thank you so much for the help.George, if I understand better exactly how you are constructing this I can provide you with a detail that does not couple the wall assemblies...... this is not a big problem..... Do you have any actual plans yet on the construction of this space - and by this I mean a section through the walls between the control room and the tracking room? Just FYI - this issues is going to exist at all of the walls - not just the walls separating those rooms...... Rod
First off (before I forget - mind is getting fuzzier by the day) loose the thought of resilient channel - not only will it not help you - it will HURT you. It will decrease your low frequency isolation. Now - I still do not have a complete picture.......... so let's see if we can't finish putting this together....... I know you have isolated walls - I do not know stud size - forget the thermafiber fire saffing inside the wall cavities - normal ordinary fluffy fiberglass is better for low frequency isolation - and this is where you always need the help the most (mid and high frequency TL values are always high in comparison), and are you framing an isolated ceiling as well as the walls - if not - exactly how are you handling this? Do you have any drawings yet? You will need those for the building permit......... Get back to me...............Yes I know that I have to solve this issue for the air gap running between all the walls besides the control room/live room. Section through the walls from control room to live room: 2 layers of sheet rock wooden studs with 3" Thermafiber FASB 2.5 PCF insulating 4" air gap and then the second wall, starting with the insulated side and ending with 2 layers of sheetrock. I'm toying with the idea of also using resilient channel but I'm not sure if it's overkill in this situation since the wall frames are already decoupled. Thank you so much for the help.George, if I understand better exactly how you are constructing this I can provide you with a detail that does not couple the wall assemblies...... this is not a big problem..... Do you have any actual plans yet on the construction of this space - and by this I mean a section through the walls between the control room and the tracking room? Just FYI - this issues is going to exist at all of the walls - not just the walls separating those rooms...... Rod
Hi Rod,
OK, the resilient channel is forgotten. Good. One less concern.
In regard to the FASB- I'm surprised. I read so much online touting the benefits of dense mineral wool which is what this stuff is. I'm just proposing to use it as the insulation that lines the walls between the studs, not as a way to fill the 4" air cavity. Are you talking about that air cavity, or are you telling me I'm better off with the pink stuff for the actual insulation of the walls?
In regard to drawings- this should be developing more over the next week. Tomorrow I have a sit down with the architect, who since I first met with him has done detailed measurements of the space, and I will also get more detailed information from the building owner. They are throwing in a bunch of the material for free- this includes the studs and about half of the sheet rock needed. So I will find out the details on the studs in the next few days. It's actually possible they will be steel since they are using steel studs in another building on the site.
I'm not building a floating ceiling. The floor above the studio sits unused currently and my best read on the situation is that it will remain unused for some time. These guys have a big mill complex on their hands and many tens of thousands of other square feet that are already in better shape to deal with. So these walls will extend from floor to ceiling. The one complicating factor is the beams I mentioned earlier, which are about 8 inches wide. Since the sprinkler layout necessitates a lot of walls along these beams, I'm just now realizing that this will be an issue that needs to be dealt with somehow.
Sorry I can't give you clear answers yet- everything here is still fluid and shifting, and I'm just trying to keep up with everything as it develops. I will provide updates. Thank you again for your kind help.
That's a bit confusing, unless you are planning to build your wall inside-out. Is that the case? Inside out walls, with studs facing the room and drywall facing the cavity? - Stuart -I'm just proposing to use it as the insulation that lines the walls between the studs, not as a way to fill the 4" air cavity. Are you talking about that air cavity, or are you telling me I'm better off with the pink stuff for the actual insulation of the walls?
goodHi Rod, OK, the resilient channel is forgotten. Good. One less concern.
I am saying that all you want in your walls is fluffy insulation - if you did an exhaustive study of wall s assemblies - you would see that fluffy outperforms higher densities down in the lower frequencies - it is just the opposite for mid and higher frequencies......... What you hear doesn't surprise me - people are constantly getting this wrong..........In regard to the FASB- I'm surprised. I read so much online touting the benefits of dense mineral wool which is what this stuff is. I'm just proposing to use it as the insulation that lines the walls between the studs, not as a way to fill the 4" air cavity. Are you talking about that air cavity, or are you telling me I'm better off with the pink stuff for the actual insulation of the walls?
I'm not building a floating ceiling. The floor above the studio sits unused currently and my best read on the situation is that it will remain unused for some time. These guys have a big mill complex on their hands and many tens of thousands of other square feet that are already in better shape to deal with. So these walls will extend from floor to ceiling. The one complicating factor is the beams I mentioned earlier, which are about 8 inches wide. Since the sprinkler layout necessitates a lot of walls along these beams, I'm just now realizing that this will be an issue that needs to be dealt with somehow. [/quote] This poses a real serious challenge on your end - although it solves some other things....... I have no idea of the spaces surrounding you - how disturbed they will be if they hear you - or you them (probably more likely the other way around) - but your isolation is now going to be determined by the flanking path that remains available - which is the ceiling that ties directly into other spaces......... RodIn regard to drawings- this should be developing more over the next week. Tomorrow I have a sit down with the architect, who since I first met with him has done detailed measurements of the space, and I will also get more detailed information from the building owner. They are throwing in a bunch of the material for free- this includes the studs and about half of the sheet rock needed. So I will find out the details on the studs in the next few days. It's actually possible they will be steel since they are using steel studs in another building on the site. Be careful with this - steel studs in commercial construction are typically 25 gauge.... and while this is fine for general use it is not good for anything having to do with low frequency........... that is the region controlled primarily by the wall stiffness - you will give up a lot of isolation is you use light gauge studs.
UbnderstoodSorry I can't give you clear answers yet- everything here is still fluid and shifting, and I'm just trying to keep up with everything as it develops. I will provide updates. Thank you again for your kind help.
Hi Stuart, The walls I'm proposing are not inside out. Here, I found the image which originally guided me:That's a bit confusing, unless you are planning to build your wall inside-out. Is that the case? Inside out walls, with studs facing the room and drywall facing the cavity? - Stuart -I'm just proposing to use it as the insulation that lines the walls between the studs, not as a way to fill the 4" air cavity. Are you talking about that air cavity, or are you telling me I'm better off with the pink stuff for the actual insulation of the walls?
External image, not preserved — original: http://www.greengluecompany.com/images/understandingTripleLeaf/Leaf-STC.gif
I'm proposing the 3rd configuration, the one which for them resulted in STC 63.
For the pink insulation in the diagram I was proposing to use FASB mineral wool blankets, but now Rod has me looking into using real pink stuff like the picture. My question about fire code refers to the open air between the insides of the two single-leaf walls.
Thank you Stuart!One of the best things about this location is that we do not have to concern ourselves with bothering our neighbors, and our neighbors are relatively quiet from what I can tell. On the north wall there is a mason who only uses the space to store materials, so he loads out once in the morning and then once in the evening. Most of the day and night it sits empty. On the east we border spare storage space- again empty and quiet most of the time. However I am concerned about the noise from the street to the west and southwest. It's not a highway but it's not a country lane either. Besides the ceiling flanking, doesn't my floor also? Is there something worse about the ceiling doing so? Soundman above linked to a post which talked about why not floating the floor is not a fatal error- does the same not apply to the ceiling? I will keep the limits of narrow gauge steel studs in mind. Now I will go do my homework in regard to the acoustic properties of fluffy fiberglass vs. Thermafiber SAFB. Thank you again for your invaluable help! That goes for everyone on the forum too, since I learned a lot indirectly before I dared ask anything.I am saying that all you want in your walls is fluffy insulation - if you did an exhaustive study of wall s assemblies - you would see that fluffy outperforms higher densities down in the lower frequencies - it is just the opposite for mid and higher frequencies......... What you hear doesn't surprise me - people are constantly getting this wrong.......... Be careful with this - steel studs in commercial construction are typically 25 gauge.... and while this is fine for general use it is not good for anything having to do with low frequency........... that is the region controlled primarily by the wall stiffness - you will give up a lot of isolation is you use light gauge studs. - This poses a real serious challenge on your end - although it solves some other things....... I have no idea of the spaces surrounding you - how disturbed they will be if they hear you - or you them (probably more likely the other way around) - but your isolation is now going to be determined by the flanking path that remains available - which is the ceiling that ties directly into other spaces......... Rod
The required firestop is at the top of the walls - not the entire cavity...........
You're welcome! :)Thank you Stuart!
OK, I think I see where your confusion is coming from. You originally said "I'm just proposing to use it as the insulation that lines the walls between the studs, not as a way to fill the 4" air cavity. Are you talking about that air cavity, or are you telling me I'm better off with the pink stuff for the actual insulation of the walls?". The truth is, the ENTIRE GAP between the two leaves of the wall is the air space. It is all one. Not just the part that looks empty there. In the diagram you linked to, that air space includes the two sets of "pink insulation between the studs" AND ALSO the empty space in the middle. All of it is the "air cavity". And ideally, it should all be filled with insulation, if you want to maximize isolation. On that drawing that you show above, they only show insulation between the studs for clarity in what they are explaining about comparing walls, but in reality if you were aiming for maximum isolation with that wall, you would fill the entire air gap with pink fluffy insulation. The term "air gap" refers to ALL of the space between the inner-leaf and the outer-leaf, even if that space appears to be occupied by insulation. It is still considered to be "air", since that's what it is, mostly. Insulation is mostly air. It is still an "air gap", even if it is filled with insulation. More correctly, it is the damped spring that forms the "S" part of the "MSM" system (Mass-Spring-Mass). Search the forum for "MSM" and also for the technically less-correct (but synonymous) "MAM". You need to understand the concept of what an MSM wall actually accomplishes and how it works, in order to properly design your room. The basic idea is that an MSM wall is a tuned bandpass filter, something like a tuned electronic circuit, or a parametric equalizer. It is tuned to one specific frequency, and it passes that frequency VERY well, while blocking all others. An MSM principle consists of two masses attached to either end of a damped spring. The "spring" is the air, the "damping" is the insulation, and the "masses" are the two leaves (usually drywall, but sometimes brick, concrete, etc). Very simply, one mass (=sheet of drywall) vibrates due to sound waves striking it, and if the frequency of that vibrations happens to be the same as the frequency that the wall is tuned to (the "resonant frequency"), then the vibration is transmitted to the other side of the wall, via the spring. In fact, the entire wall will vibrate in sympathy with the original sound wave, and transfer the vibration to the other side really well. so sound goes straight through the wall at the resonant frequency. But at all higher frequencies, the wall refuses to resonate and PREVENTS the vibrate from getting through: it blocks the sound, (kind of like a parametric equalizer tuned to a specific frequency with a narrow bandwidth and very high boost). Of course, the trick here is to tune the wall to a frequency that is well below what humans can hear, or at least well below the lowest frequency that you need to stop. Obviously, the wall doesn't act like a perfect bandpass or notch filter: it passes sound at the resonant frequency, and passes it a bit worse at frequencies close to that, then gets even worse at passing as you get further away from the resonant frequency, etc. up to about 1.4 times the resonant frequency, at which point it then starts blocking. At 2 times resonance, it does a decent job of blocking. So for a studio you normally want to design the wall to resonate at something like 10 Hz or less, in order that it does a good job of blocking at 20 Hz and above, which is generally considered to be the lowest frequency that humans can hear. The resonant frequency depends mainly on two things: the total mass of the leaves, and the size of the air gap between them (and also to a certain extent on the insulation). In order to DECREASE the resonant frequency you can either add more mass, or increase the air gap (or put more insulation in the air gap to some extent). Or all three. Theoretically, two layers of 5/8 drywall on each side of an 8 inch air gap (as in your diagram, above) will give your wall a resonant frequency of roughly 20 Hz if you do not have insulation in it, or about 14 Hz if you do have insulation in it. So the damping improves the resonant frequency considerably: Without, it isolates well form 40 Hz up, and with insulation it isolates well from 28 Hz up, which is nearly an octave lower! But without any insulation at all you would also NOT get the STC-63 shown in that diagram: It would be more like only STC-50. Leaving out the insulation in an MSM wall will cost you both in terms of resonant frequency (too high), and also in terms of transmission loss. And if you were to add even MORE insulation, filling the remaining empty space inside that wall in your diagram, theoretically you would improve the isolation by another 4 dB, give or take a point. Yes, they TYPE of insulation makes a difference too. I say "theoretically" above, because all of those numbers come from equations based on a perfect world. The world isn't perfect. Isolation depends on a lot more than just what is in that diagram, such as for example how well you build it, how well you seal it (both leaves must be absolutely hermetically sealed, airtight), how well you decouple the two sides, etc., the quality of the materials, as well as on the design and construction of the floor, ceiling, walls, doors, electrical system, and HVAC system. To name just a few... All of those will DECREASE the actual isolation, dragging it down form the theoretical numbers. It will never get better, always worse. (And don't forget Murphy...) Another thing to consider: It isn't just one wall that is the MSM system, but rather the entire room! All the walls and the ceiling need to be built the exact same way, or the isolation of the entire room suffers, and is reduced to that of the weakest point. So if you made a mistake and built just one small section of one wall like the middle part of the above diagram, then your ENTIRE ROOM will be no better than STC-53 or so, no matter how well you build the rest of it. You can't just think "Well, the road is to the west of my room, so I'll just build the west wall as STC-63, and the others as STC-53". That won't work: if you did, your entire room would be STC-53. You would have wasted your time and money on making the west wall better, as it would do practically nothing for you. The same with windows, doors, HVAC, etc. Everything has to be carefully designed to the same level as everything else, or the entire thing will be trashed down to the level of whatever is the worst part.The walls I'm proposing are not inside out. Here, I found the image which originally guided me:
Yes. Everything that mechanically connects your inner-leaf to your outer-leaf is a potential flanking path. The question is: how bad is the flanking? With a good thick dense concrete slab poured directly on grade, flanking through the floor is pretty much negligible for most practical studio purposes. you can ignore it. BUT!... For your average house floor above the basement or garage, it is a huge deal. That's why most people here end up building their studios in their basement or garage, rather than upstairs. Trying to isolate a typical house wooden floor ain't easy, or cheap. What we don't know about YOUR case, is what your floor is made of, since you didn't say! It seems to be pretty solid from your comments, but finding out how it actually is constructed, is very important. What you said was "They are 100+ year old hardwood. The building is an industrial mill building", so I'm assuming that the floors are capable of supporting some serious weight, and are therefore pretty massive already, but details are needed!Besides the ceiling flanking, doesn't my floor also?
Everything large flat and massive is an acoustical leaf! The floor certainly is. Even a concrete slab on grade is a leaf. The question isn't "is it leaf", but rather "how much of an issue is that leaf". The answer to that depends on how massive it is, how well damped it is, how well decoupled it is, what is on the other side of it, how loud you are, how quite you need to be, and roughly a kazillion other things (give or take a few jillion... :) ).They were not finished like a nice hardwood floor would be so I didn't get the impression that they were acting as an actual acoustical leaf.
Probably, depending on how the ceiling is constructed, etc. The same kazillion things also apply to the ceiling. But ceilings are usually more flimsy than floors (less massive), are less likely to be damped, etc. However, once again, you need to find out.Is there something worse about the ceiling doing so?
I'd suggest that you first do some homework on MSM walls and how they work. Like Rod already said: there is a difference between fiberglass and rockwool, but it isn't huge and either will work fine as damping insulation in an MSM wall. So just go with the fiberglass! But do take the time to learn about MSM, since your entire studio isolation depends on getting that right. It's a biggie! Much bigger than the choice between pinkyfluffy fiberglass, 703 and rockwool. Accidentally substituting rockwool for fiberglass won't make a huge difference to your wall, but accidentally substituting 1/2" drywall for 5/8 drywall certainly will, and so will accidentally substituting a 2" air gap for an 8" air gap, or accidentally leaving a 1/16 crack 10 feet long under the wall because your floor is uneven ad you didn't think caulking was important, or accidentally letting a single nail bridge your inner leaf to your outer leaf, or accidentally putting two electrical boxes back-to-back on a wall, or accidentally using ordinary thin window glass instead of thick laminated glass in your windows, or accidentally putting a third leaf up close to your wall, or many, many, MANY similar "accidental" issues that really don't seem important at first glance but in actual fact are huge issues, as they affect the basic MSM principle that makes your wall work in the first place. Or not work, as the case may be... Personally, I had no idea how important it is to understand MSM until I started looking into it, and now I realize that MSM is practically the entire deal! If you get your MSM wrong, then nothing else that you do matters: the studio will be a flop. And if you get MSM right, then everything else will be a whole lot easier. Understanding how MSM works is the key to isolating your studio, period. So that's where I'd suggest you put your research efforts into! Once you get your head around that (and it isn't intuitive at all) then the rest suddenly seems logical, and not so hard to grasp at all. - Stuart -Now I will go do my homework in regard to the acoustic properties of fluffy fiberglass vs. Thermafiber SAFB.
Thank you Stuart, rest assured I will be doing some reading on MSM. I truly appreciate the time you took to write that. Some of the concepts I had picked up from reading here (e.g. the importance of hermetically sealing the complete leaf, the threat presented every time you puncture the leaf with something like an electrical box or cable, etc- I'm hoping to mount everything I possibly can on the surface including the outlet boxes and conduit- etc.) Actually I'm dreading explaining to the building owner that I need them to pause during the build so that I can seal the first layer of drywall before they install the second layer, and also dreading the complexity involved in planning a future-proof cabling network and getting it into place acoustically secure as the build goes up. It's just an insane number of things that have to all be juggled at once.
But out of everything you told me, the fact that the entire cavity between the leafs is functionally monolithic, and that I can fill those cavities with pink stuff and actually have it benefit me- that's fantastic. That solves the biggest code problem so far for me, and in a way that's actually affordable and beneficial to the function.
I will provide updates after meeting with the architect and speaking with the building owner. I will get all the information I can on the existing floor and ceiling construction as well. Thank you again!
For both George and Stuart,
Be careful with what you do in the cavity - As I noted the required firestop is at the top of the wall - this cannot be accomplished with fluffy fiberglass.
In addition - you are in a commercial setting here - and there are fire assemblies required between tenant spaces in these Use Groups (Business) - this means that your wall system HAS TO BE a rated tested assembly.
You cannot alter the assembly from the manner in which it was constructed and tested except as noted in the UL (or FM) listing.
I have never encountered a UL assembly using either fiberglass or rockwool that indicated you could fill the cavity with insulation.
In fact they specify not only the type of insulation that is approved - but the actual thickness that is to be used.
This is taken from the ANSI/UL 263 - Design Guide Info:
And this regarding maintaining the design as tested:VI. WALLS AND PARTITIONS The ratings for walls and partitions apply when either face of the assembly is exposed to the fire unless indicated otherwise on a specific design. Flashing and corner details may vary from those described in a design provided structural equivalency is maintained and similar materials to those specified in the design are used for supports, fasteners and flashings. The hourly rating of a load-bearing assembly also applies to the same assembly when it is used as a non-load-bearing assembly. The size of studs is minimum unless otherwise stated in a design. The spacing of studs is a maximum unless otherwise stated in a design. Spacing between parallel rows of studs are minimums unless otherwise stated in the individual designs. Gypsum board thicknesses specified in specific designs are minimums. Greater thicknesses of gypsum board are permitted as long as the fastener length is increased to provide penetration into framing that is equal to or greater than that achieved with the specified gypsum board thickness and fasteners. Additional layers of gypsum board are permitted to be added to any design. Orientation, vertical or horizontal, of the application of gypsum board in walls and partitions is specified in the individual designs. Except when gypsum board is allowed to be applied horizontally in the individual wall designs, horizontal butt joints of vertically applied gypsum board should be backed by the same type studs as specified in the design. Alternatively, minimum 25 gauge steel framing with a minimum attachment face of 1-1/4 in. may be used for the backing. Both edges of the gypsum board forming the horizontal joint should be attached to the backing with the same screws and spacing as specified in the design for the attachment of the gypsum board edges, then finished as specified for the vertical joints. Horizontal butt joints on opposite sides of the studs in single-layer applications should be staggered a minimum of 12 in. unless otherwise stated in the individual designs. Horizontal butt joints in adjacent layers on the same face of the assembly in multiple-layer applications should be staggered a minimum of 12 in. unless otherwise stated in the individual designs.
As well as this comment regarding the same:When a test assembly complies with the acceptance criteria, a detailed description of the assembly, its performance in the fire test and other pertinent details such as specification of materials, Classification coverage and alternate assembly details are included in a Report for the test sponsor. Sponsors may provide copies of the complete Test Report upon request. The Report also contains a summary of important features of the rated assembly. These summaries are also published in this Directory. Variations from the published specifications should be considered as not being investigated by UL.
OK - as to where I am going with this, all UL wall assemblies requiring or allowing insulation (some don't - if it is not required as a part of the assembly it may be allowed - if it is not required or noted as allowed it cannot be added) specify not only the type of insulation - but the thickness and placement as well........ You note above what is allowed to change - for example - stud size is minimum, spaces between structures are minimum, drywall thickness and (or) number of sheets is minimum, but nowhere does it state that you can alter the insulation in the cavity. ANSI/UL Assembly No. U307 is for a non-bearing wood frame partition, 2x4 min studs @ 16" or 24" o.c. with a minimum of 1 layer 5/8" gyp each face with a minimum 1" air space between wood frames, with optional 3 1/2" fiberglass insulation in the stud cavity - friction fit......... For this assembly you cannot substitute rockwool - and regardless of the stud size or bay spacing you cannot increase the thickness of the insulation. When you leave the residential world there are a whole new set of rules that apply......... Don't be getting into trouble........... RodFire-resistance ratings apply only to assemblies in their entirety. Except for those separately rated structural members supporting tested assemblies, individual components are not assigned a fire-resistance rating and are not intended to be interchanged between assemblies but rather are designated for use in a specific design in order that the ratings of the design may be achieved. All ratings are based on the assumption that the stability of structural members supporting the assembly are not impaired by the effects of fire. The extent of damage of the test assembly at the rating time is not a criteria for the rating. The specifications for materials in an assembly are important details in the development of fire-resistance ratings. Those materials provided with an "*" in the design text are eligible to be produced under the Follow-Up Service Program of Underwriters Laboratories Inc. Information identifying such materials and the Classified companies authorized to provide the materials are located in the product category section of this Directory. The appearance of the Classification Mark on the product is the only method provided by UL to identify products that have been produced under its Follow-Up Service.
I wish we could get a picture or three of this building...
I will follow up with pictures but this will take some time. We will sign a lease next week. The current tenant will not vacate until the beginning of June. He's a used furniture dealer and has the place loaded to the gills with antiques and assorted junk, so I will get inside then and take some more meaningful pictures. I will try to get some exterior shots before then. I met for two hours with the architect today. I found out about the construction of the existing ceiling today but not the floor. It's mill style construction so there are no joists- basically it's two layers of hardwood planks followed by two layers of hardwood flooring installed over the years, totaling about 4" of hardwood. Does that spell flanking doom? Part of our discussion today covered ways we could drop a ceiling in if they eventually put a business in upstairs. He offered a few solutions that sounded like a real pain in the ass so here's hoping that it stays quiet up there for a good long time. My feeling is that by the time they make something of the second floor, we will have a good sense of whether further financial investment in the space is justified. The studs are in fact steel so there's another compromise. I think the ease of installing these kind of walls and the ease with which they can be recycled has much to do with the very reasonable quote I got on the labor for the build out. No one seems to think there will be any kind of problem with filling the gap between the walls with fiberglass, and the building owner mentioned he had applied this technique elsewhere without trouble from the town. Regardless once we have a finished plan it goes to the town for approval, so we will have their blessing before anything gets built. Other details that have come up... the electric panel will need to be moved a little, not a huge deal since they are running new wire and outlets for us anyway. We have to come up with a plan for ventilation. I know there has been some good discussion about that here so I will be doing more reading. I have to come up with 3 really good acoustical doors. I read the thread about building them out of MDF and it sounds like its own damn problem. More reading to do there. We're getting quotes from glaziers for glass right now. Again more reading there since some of them are offering good deals on tempered glass while I know that the preferred solution is laminate. The building owner keeps talking to me about Lexan, I think because he doesnt' want to lift real glass. I have to figure out the trade off since it seems like everything is a trade off. I wish I had another decimal point in my budget.I wish we could get a picture or three of this building...
By the way, do you have Rod's book? If not, then I'd suggest that you get it! He covers the basics of electrical and HVAC in there, as well as doors, windows, ceilings, floors... Get your architect and contractor to read it too. Some stuff they might be used to doing one way for "normal" buildings, could in fact not be the right way to do it at all for a studio.
- Stuart -
OK - after this I am going to drop the whole thing - but first I will try to explain life in Connecticut - Architects, Local Building Officials and the regs........ Architects think that they know everything - but no very little when it actually comes down to code - which is why the good ones hire code consultants to make certain they are not designing problems into their buildings. Building officials are (supposedly) experts in the code - but their drawing review is only to verify that the designed components are meeting the code regulations......... they do not go through all of the various design manuals and verify if the actual design meets the test reports - all they do is verify that you have a UL assembly in your design that meets the required rating. If you were to go to him and say:No one seems to think there will be any kind of problem with filling the gap between the walls with fiberglass, and the building owner mentioned he had applied this technique elsewhere without trouble from the town. Regardless once we have a finished plan it goes to the town for approval, so we will have their blessing before anything gets built.I wish we could get a picture or three of this building...
they are (by law) supposed to say "No" - and you are then required to go to the state building official and apply for a modification to the code. The state building official is the ONLY person allowed to grant a modification (They are the Authority Having Jurisdiction - or AHJ) not the local official. The local officials only role is to enforce the code. The code specifically states that the issuance of a building permit is NOT an approval of the plans as detailed, does not grant a modification of any code requirements - but is (rather) just permission to proceed with construction - and that anything existing in the plans which is not in conformance with the code shall be required to be removed and corrected when discovered - even after construction is completed and a Certificate of Occupancy is issued - completely at the cost of the permit holder. This is taken directly from the Connecticut Supplement to the 2003 Edition of the IBC (wehich is the State Building Code)"mister building official - what we designed does not meet the UL approved design - is it ok if we vary from it"
The bold and underline above is placed by me just so that you don't miss the point. The local official is NOT supposed to approve anything that is not code compliant...... The code then leads to this:(Amd) 104.1 General. The building official is hereby authorized and directed to enforce the provisions of this code. The building official shall have the authority to adopt policies and procedures in order to clarify the application of its provisions. Such policies and procedures shall be in compliance with the intent and purpose of this code. Such policies and procedures shall not have the effect of waiving requirements specifically provided for in this code, nor shall they have the effect of establishing requirements in excess of those set forth in this code. (Add) 104.1.1 Rule making authority. Pursuant to the provisions of subsection (a) of section 29-252 of the Connecticut General Statutes, the State Building Inspector and the Codes and Standards Committee shall, jointly, with the approval of the Commissioner of Public Safety, adopt and administer a State Building Code for the purpose of regulating the design, construction and use of buildings or structures to be erected and the alteration of buildings or structures already erected and make such amendments thereto as they, from time to time, deem necessary or desirable
So what your architect is suggesting is that he/she is aware of the fact that this is a code violation - deliberately duping an ignorant building official into issuing a permit on a design that he/she knows is in violation of the code - sidetracking the code itself, ignoring the statements made by the authority that tested the assembly - which could possibly cause a failure in the system........ and that somehow this is all ok because it's been done before. Well guess what, doing it wrong and getting away with it does not make it right........... regardless of how many times it happens. I offered to provide you (without cost) a proper detail to firestop the assembly that would be code compliant - would not compromise the acoustic isolation and yet you choose to do it wrong....... One of the many things I do in life is code consulting - and I do it reasonably well -in fact I am highly respected in this regard by the State Building Officials Office - I do not believe in deliberately doing things wrong - and I do not involve myself in projects (even here) that set out with that intention. So I wish you the best of luck - and leave you in Stuarts capable hands..........Amd) 104.10 Modifications. Modifications, variations, or exemptions from and approval of equivalent or alternative compliance with the requirements of this code shall be in accordance with the provisions of Sections 104.10.1 through 104.10.6. (Add) 104.10.1 State Building Code. The State Building Inspector may grant modifications, variations or exemptions from, or approve equivalent or alternative compliance, with the State Building Code where strict compliance with the State Building Code would entail practical difficulty or unnecessary hardship, or is otherwise adjudged unwarranted, provided that the intent of the law shall be observed and public welfare and safety be assured. Any person aggrieved by any decision of the State Building Inspector may appeal to the Codes and Standards Committee within 14 days after mailing of the decision in accordance with subsection (b) of section 29-254 of the Connecticut General Statutes. (Add) 104.10.1.1 Action on application. The application for modification, variation, exemption from or approval of equivalent or alternative compliance with the requirements of the State Building Code shall be made on a form supplied by the State Building Inspector available from the local building official or the Office of the State Building Inspector, which shall be forwarded by the applicant to the local building official. Any such application received by a local building official shall be forwarded to the State Building Inspector by first class mail within 15 business days of receipt by such local official. The application shall include the local building official’s comments on the merits of the application, and shall be signed by the local building official, acting building official or provisional building official. (Add) 104.10.1.2 Records. The application for modification, variation, exemption or approval of equivalent or alternative compliance and the decision of the State Building Inspector shall be in writing and shall be officially recorded with the application for a building permit in the permanent records of the building department.
When it comes to code in the USA, Rod, I'm not so sure I'd consider my hands all that capable! I don't even live there! I understand the issue with fire blocking, and I wasn't even really talking about that point at all here, or suggesting anything contrary to what you said on that, I hope! Sorry if it sounded that way. Rather, I was commenting on the isolation aspects (how/why MSM works), not the code or construction aspects. But I am curious as to what the code issue is with filling the entire wall cavity with fiberglass, as opposed to leaving an empty airspace in there. I don't doubt at all that code might not allow it, but I'm curious as to WHY that might be. I would have thought that anything that slows down air movement inside a wall would be good for improving fire rating. So is it just an issue of that configuration never having been tested and approved, or is there an underlying reason why filling the entire cavity could present an additional fire risk? I'm guessing that it's a matter of "never been tested, therefor not approved", since for an ordinary wall with 2x4 single studs, drywall on both sides, and 3 1/2 inch insulation, the cavity actually is filled completely. Not doubting your expertise here, Rod: Just curious as to the reason why fully filled cavities deeper than 3.5" might not be allowed. (And I'm certainly not suggesting that a fully filled cavity is a substitute for fire blocking!) - Stuart -and leave you in Stuarts capable hands..........
Stuart,
when assemblies are tested they put them in a contraption and burn them until failure - and then rate them.....
If the test was with 3 1/2" insulation in the cavity and you add more to it - the additional insulation could stop the dissipation of heat buildup inside of the wall cavity and actually cause the structure inside to fail faster than what occurred in the test.......
It is always possible that this may not occur - BUT - seeing as it was never tested in that configuration - it was never rated in that configuration - and the code requires a rated tested assembly - period - no questions - no substitutions - no modifications to the assembly - it just is not allowed.
And this is not a matter of common sense - when it comes to fire assemblies - some things that you might think would be fine just are not.........
some of these assemblies are tested such that you cannot even substitute the drywall from one manufacturer to another - you can only use the specified drywall of the specified type manufactured by the specified manufacturer.
Although this is more critical with bearing walls, columns and floors - it is the code none the less when it comes to non bearing walls as well........... and I really do have a serious issue with deliberate attempts to circumvent the codes.
In fact - the last decent sized project i worked on (completed it in November last year) I had to go to the state building official's office because the Architect had screwed up the design and wouldn't fix it.
She kept saying that she knew what she was doing (posturing in front of the owners) - that she was a building official for a town in CT and she knew the code - and it wasn't until the State Building Inspector's office came back and answered my 6 page letter listing issue after issue - with them responding that I was correct - that she finally made the changes she need to make (most of which i provided the actual details for).
She then tried to convince the owner that she got away with this all over the state and that I was holding them to a higher standard than I should be - to which I responded that they could either shut up, pay the freight and let me do this the right way - or they could petition the owner of my company to replace me and do what they hell they pleased - but as long as I was on the job it would be done right...........
Seeing as this poster has decided to accept things however they come out- then all that's left are acoustic issues - and I am not going to waste my time with this - my time is too precious to throw it away with this sort of thing.......
Enjoy my friend.........