Not sure but you can add rubber matting between the rock layers to add mass.
Do rock, rubber, rock, rubber. Or look at some of the mass load vinyls out there.

pan60, post: 422831, member: 40762 wrote: Not sure but you can add rubber matting between the rock layers to add mass.
Do rock, rubber, rock, rubber. Or look at some of the mass load vinyls out there.

You can add rubber to add mass according to who?

Is the rubber the same mass as the as yet unspecified layers the op is talking about? If it isn't then you would not use rubber....and you must consider the cost in any event.

Mass loaded vinyl has no place in attempting to contain sound.

As for a rule for installing sheathing on light weight metal studs, the shear ability of the fastener has to be considered but first and foremost you have to explain how the studs are supported vertically in order to give an answer.

Space, post: 422942, member: 32398 wrote: You can add rubber to add mass according to who?

Is the rubber the same mass as the as yet unspecified layers the op is talking about? If it isn't then you would not use rubber....and you must consider the cost in any event.

Mass loaded vinyl has no place in attempting to contain sound.

As for a rule for installing sheathing on light weight metal studs, the shear ability of the fastener has to be considered but first and foremost you have to explain how the studs are supported vertically in order to give an answer.

Thank you. I am NOT planning on using any rubber in my walls. There is 1 layer of existing drywall up. I'm considering pulling it down for 2 main reasons.
1) So I can put a layer of OSB 1st which I've done before. It made hanging acoustic treatment so easy later because I did t have to hunt for studs.
2) so I can do it all right and air tight. The layer that is up is typical office style construction and is very obviously not airtight.
I'm not sure yet how the structure is vertically supported. As soon as I get in there I will investigate and report back here, hoping for good direction.

Thanks for the solid reply!

Space, post: 422942, member: 32398 wrote: You can add rubber to add mass according to who?

Is the rubber the same mass as the as yet unspecified layers the op is talking about? If it isn't then you would not use rubber....and you must consider the cost in any event.

Mass loaded vinyl has no place in attempting to contain sound.

As for a rule for installing sheathing on light weight metal studs, the shear ability of the fastener has to be considered but first and foremost you have to explain how the studs are supported vertically in order to give an answer.

I thought I might as well ask if there IS a rule of thumb? Using standard fasteners and method?

there is a correct way to do what you are trying to do .... it's called "[[url=http://[/URL]="http://www.buildgp…"]sound board insulation[/]="http://www.buildgp…"]sound board insulation[/]".

start with osb and then make a sandwich of 5/8" sheet rock soundboard and then 1/2' rock. seal with caulk.

the 3 different layers will have different resonant frequencies thereby cutting transmission though the wall. a layer of Limp Mass Vinyl can be applied if needed.

Mass Vinyl or rubber is not sound proofing but neither is adding sheet rock.
Limp Mass Vinyl just means the mass is Limp Mass loaded and not Mass loaded.
Do some homework, rubber, Vinyl's and yes even lead have been used to load a membrane and or wall.
It will take more then just some sheet rock to contain the sound, and stop or moderately tame transmission.
As the question imparted loading, he got my two cents.

"It will take more then just some sheet rock to contain the sound, and stop or moderately tame transmission."

I remember the op's budget...it was ...no budget. So you can spend that any way you want. But when it come to spending real cash, what you suggest is inaccurate.

A Limp mass is the goal...which is why SAND is always an interesting item. Problem is...try to contain sand!!!

Limp Mass Vinyl (LMV) is per square footage too costly per isolation reduction...no one suggests it unless we are trying to isolate a construction site, which is what it is or rather what it was developed for.

Maybe you should read a few books as a New Years resolution:)

Kurt Foster, post: 422961, member: 7836 wrote: there is a correct way to do what you are trying to do .... it's called "[[url=http://[/URL]="http://www.buildgp…"]sound board insulation[/]="http://www.buildgp…"]sound board insulation[/]".

start with osb and then make a sandwich of 5/8" sheet rock soundboard and then 1/2' rock. seal with caulk.

the 3 different layers will have different resonant frequencies thereby cutting transmission though the wall. a layer of Limp Mass Vinyl can be applied if needed.

Jesus Kurt. You know as well as anyone this is Internet myth.

Space, post: 422971, member: 32398 wrote: Jesus Kurt. You know as well as anyone this is Internet myth.

i guess it's one that i have perpetuated ... i built two studios using soundboard ... one was a building that was unusable when it rained due to the sound of the rain hitting the roof ... we put up soundboard and the problem went away.

i also used the stuff in my studio (KFRS) on the walls, to plug windows and as a way to tame hi reflections all with great success.

http://www.acoustiblok.com/

http://www.fiberboard.org/index.php?option=com_content&view=article&id=55&Itemid=61

http://www.buildgp.com/hushboard-sound-deadening-board

http://www.soundproofingcompany.com/soundproofing-solutions/soundproofing-walls/

so 5/8" fire rated sheetrock would not have corrected the issue? It is, as you are illustrating, a damping issue, and the mass would have complimented that.

I would agree that serves as a great limp mass loading product.
But mass loaded vinyl I don't believe qualifies as limp mass loaded vinyl was it is attach and anchored, only suspended as I understand limp mass to be. I'm not sure it would continue to qualify as limp. On a floor yes depending not on wall. Unless maybe if it was a decoupled floating wall?
Maybe you should read up on recycled rubber as a New Years resolution. :)
The reason I mentioned rubber is it is recognized and a very nice absorptive product and it adds a great deal of mass loading. So bang for the buck IMHO, it would far outweigh three layers of rock as to adding mass and damping sound.
But in the given environment nothing is truly going solve the issue here because if we want to contain something we cannot have any holes now do we?
I'm not here to argue I offered a solid suggestion ( not the only way to skin a cat but again there are other issues here ), take it or leave I don't care.

"But mass loaded vinyl I don't believe qualifies as limp mass loaded vinyl was it is attach and anchored, only suspended as I understand limp mass to be. I'm not sure it would continue to qualify as limp. On a floor yes depending not on wall. Unless maybe if it was a decoupled floating wall?"

Could you speak clearly?

"Or look at some of the mass load vinyls out there."

You did say this?

i have never used limp mass vinyl ... i was suggesting it in the context of if needed or in other words "if you like you can" .... sorry if i didn't communicate that correctly.

Space, post: 422973, member: 32398 wrote: so 5/8" fire rated sheet rock would not have corrected the issue? It is, as you are illustrating, a damping issue, and the mass would have complimented that.

yes Brian, i'm sure it would have .... soundboard was less than 1/2 the cost and 1/2 the weight ..... lifting sheets of 5/8" fireboard 14 feet was not something i wanted to get into ....

i do not dispute your abilities or knowledge ... in fact most often i deffer to your remarks but it does occur to me sometimes that what some propose (while totaly correct) is often overkill for the intended purpose. often what i suggest is a guerrilla approach that may just do the job. if it doesn't no harm done ... one can always go even further if they wish.

I love ya Kurt....

Space, post: 422977, member: 32398 wrote: I love ya Kurt....

right back at ya' Brian .... i really do think you "rock". RO's lucky to have you as a contributor.

Sorry, I am a bit under the weather, let me try again.
I am familiar with mass load vinyls.
Mass loaded vinyl is a product limp mass loading is a way of construction.
If the mass loaded vinyl is sandwiched between two sheets of rock, it would not ( as I understand ), qualify as limp mass loading ( short of the wall serving as one large diaphragm ).

So, mass loaded vinyl, I don't believe qualifies as limp mass loaded vinyl when it is attach and anchored, but only if it is suspended. This is as I understand limp mass loading to be. Rolled out as a floor underlayment yes, depending.

Does that make sense?

I think we are discussing Phillip Newell and his approach to isolation is this correct? He is a leader in the field.

Although I am familiar with some of his work, I am honestly not really up on his design methods. I would have to do some research on his design methods to answer you on that.

". This is as I understand limp mass loading to be. Rolled out as a floor underlayment yes, depending.

Does that make sense?"

No. MLV has no place in an physics driven or acoustic driven sound proofed type of environment. It is specifically, MLV, a construction type of sound dampen material.

It was developed, mlv, as a means to cut sound from bothering the outside world, outside of that it is not a >goto< product in the the arena of small room acoustical environments.

Yes, MLV stands for Mass Loaded Vinyl. Limp Mass Loading with say Vinyl, Limp Mass Loaded Vinyl, would not be Limp Mass Loaded but only Mass Loaded.
And Mass Loaded Vinyl is used in Limp Mass Loaded system.
And without a complete air tight seal you are not get the benefit of a limp Mass Loaded system anyway.
The best you can do without an airtight system and isolation all you can get is at best a marginally good Mass Loaded system.

Explain a limp mass loaded vinyl system.

Suspended Mass Loaded. Not anchored so as to create a diaphragm effect such as a drum head.
The Mass Loaded Vinyl has to be limp.
If it was laid out between rafters, it would be limp Mass Loaded. If it is woven between a staggered studded wall I would say if was limp Mass Loaded. If you where to say male some bass traps and layered Mass Loaded Vinyl between some mineral wool I would call that limp Mass Loaded. If you attached it to a frame the it would only be a Mass Loaded system.

It is limp no matter how you install it. It is 1. VINYL and 2 lead and 3 not a solid product.

The lead is encapsulated in the bonded vinyl to mitigate low frequency vibration. It has an STC of about 27 STC

Nope not limp unless it is limp.
Lead sheeting would not be a limp mass product either, only a Mass Loading product. Lead shot in a wall cavity would be Limp Mass Loaded product, same a sand.
Sand in a cavity or in-between joist or ratters would be Limp Mass Loading, one it is mixed with portland to make cement it is then only a Mass Loaded product.

Thanks for the healthy discussion guys!
My exhaustive searching and reading on this board has convinced me that the best bang for buck method will be airtight layers of 5/8" Sheetrock. Rod Gervais states it over and over and over again in the 200 pages of the construction/acoustics threads. I built a studio with OSB/soundboard/drywall and the isolation was medium...meaning it didn't do much. I am considering OSB/drywall/drywall. OSB as a base layer makes hanging treatment a breeze later...no stud hunting!!

Thanks again guys for all the help.

pan60, post: 422989, member: 40762 wrote: Nope not limp unless it is limp.
Lead sheeting would not be a limp mass product either, only a Mass Loading product. Lead shot in a wall cavity would be Limp Mass Loaded product, same a sand.
Sand in a cavity or in-between joist or ratters would be Limp Mass Loading, one it is mixed with portland to make cement it is then only a Mass Loaded product.

While I would love to do this type of thing for hours on end, I simply refuse to engage with a subject that becomes word specific and at each juncture another word is entered to modify the position.

"Nope not limp unless it is limp.
Lead sheeting would not be a limp mass product either, only a Mass Loading product. Lead shot in a wall cavity would be Limp Mass Loaded product, same a sand.
Sand in a cavity or in-between joist or ratters would be Limp Mass Loading, one it is mixed with portland to make cement it is then only a Mass Loaded product."

Mass loaded Vinyl is a limp product. It has no place in this kind of discussion. You brought it in and I am taking it out.

All the items you mention, lead, sand, et. al. are in fact limp. You can refer to them in any way you wish, but to what you and I are talking about is Mass Loaded Vinyl...it is in fact limp...and you can place it in the corner, on a window over your head in a basement on the Christmas Tree...it will still be Limp!

"The Mass Loaded Vinyl has to be limp."

And in fact it is...this is in fact the end of this distraction sir.

"
I simply refuse to engage with a subject that becomes word specific and at each juncture another word is entered to modify the position.
"

That is not the case my point from the start was that if you sandwich MLV in between sheetrock layers it is no longer limp mass but it is constricted or constrained ( not sure of the exact term ). I simply made a correction to a comment and you turned it into a debate not me.
All this started over me recommending rubber as an alternative to multiple layers of rock. And that it a good solid recommendation.

Noah Shain, post: 422826, member: 47197 wrote: Hi all
I can't find specs for lightweight steel stud load limitations. I've done a bit of searching here and on the web.
Anyone know a rule of thumb?
Can I put 3 layers up safely?
Thanks!!!

No sir, you cannot. You may be able to install 2 layers, but all things considered, if three layers are to be spec'ed then you would most likely move to a structural guage stud.

Here is the load chart for steel studs http://www.ssma.com/filebin/pdf/SSMA_Technical_Guide_10-14.pdf
The question is very light on information. How high is the wall? what thickness of drywall? 3 layers on each side?
Short answer is no.
Light gauge (under 33mil) is only rated to 10 PSF maximum and that is dependent on wall height, center spacing, and the gauge.

I have know idea if I am opening up a pandora box here because acoustics is not my fort-ay. I'm not following the thread in depth either, but perhaps my injection about now will clear up anything missed in regards to Pan's POV. This link was sent to me in hope I shared it with the house for the mutual advancement of us all.
[[url=http://[/URL]="https://www.aslsoun…"]https://www.aslsoun… Glue Vs. Mass Loaded Vinyl.pdf[/]="https://www.aslsoun…"]https://www.aslsoun… Glue Vs. Mass Loaded Vinyl.pdf[/]

Space, post: 423030, member: 32398 wrote: No sir, you cannot. You may be able to install 2 layers, but all things considered, if three layers are to be spec'ed then you would most likely move to a structural guage stud.

Thanks for the advice!
Are you speaking from experience? Not meaning any disrespect...just trying to be complete in my investigation!
Thanks and happy new year!!!

dprimary, post: 423032, member: 15341 wrote: Here is the load chart for steel studs http://www.ssma.com/filebin/pdf/SSMA_Technical_Guide_10-14.pdf
The question is very light on information. How high is the wall? what thickness of drywall? 3 layers on each side?
Short answer is no.
Light gauge (under 33mil) is only rated to 10 PSF maximum and that is dependent on wall height, center spacing, and the gauge.

Thanks for this!!! Even though the prognosis is not good.
The walls are 16' high. They are already up. Framed from floor to big ass laminate beams. The BIG ASS kind. 1 layer of 5/8 per side. I was planning on adding 2 layers on 1 side and just sealing the other. The place is already built as "office space". I'm hoping to move in, add some mass, seal her up good and go to work. I don't have the keys yet so I can't be sure of what gauge studs are there. I poked around a bit and noticed that SOME of the studs are BIG FAT RED ones and some are skinnier silver ones. Are you impressed with my tech knowledge? Yeah...me neither. I'll do a more thorough investigation very soon and report back.
Again, thanks so much for your time and help.

I always get shot down for posting in this section, but I'll ask a question. Nothing to do with what the walls are made of, but simply a mechanical issue. The question was to do with lightweight studs holding the weight of increased layers. If the wall material is not touching the floor, then all the weight is on the fixings and the studs. If the studs are freestanding, then the wall weight is on the point where the studs touch the floor, and the area where the weight transfers is the interesting area, and thin, lightweight stud material will deform, compress, shear as appropriate. The number of layers and the trough fasteners to the stud dictate the potential for flex, but increased layers usually prevent studs flexing, rather than encourage it because the sandwich has increased resistance to bowing. If the wall materials are actually touching the floor, rather than being supported by the stud, then the stud is not carrying the weight of the sheeting at all, simply preventing it toppling.

So sure the answer to this one is that the vital issue is if the wall materials touch the floor, transferring their weight downwards - and if this is the case, the stud loading is actually less vertically as more wall is added, because any joist style top loading is also spread onto the panels.

Or, have I got it wrong again? In building construction, the studwork is designed to support the loads from above, plus the modest loads of things hung from the walls.

Thanks for this answer! I haven't put the wall covering up yet...I'm just planning. Something to consider...spreading the load to the floor.

Thank you!

"The number of layers and the trough fasteners to the stud dictate the potential for flex, but increased layers usually prevent studs flexing, rather than encourage it because the sandwich has increased resistance to bowing. If the wall materials are actually touching the floor, rather than being supported by the stud, then the stud is not carrying the weight of the sheeting at all, simply preventing it toppling."

Wrong answer.

My hair has gel in it and the more vibration is applied to my hair, the more my hair flexes! I increased the gel. I increased the gel mass to a higher psi content and my hair started falling off from weight versus fastener strength ratio.

There is a reason why you will seldom find any information on applying more than two layers of sheathing on a light weight stud.

But let me discuss Mass Law first. Mass Law dictates that with every doubling of mass you get a 6 dB increase in isolation. So if you have one sheet of 5/8 rock and want to increase according to mass law, you double to 2 layers of 5/8 sheetrock. If you want to get the next 6 dB increase you have to add to the existing 2 layers by 2 more layers. That is four layers.

Anyway:
One is that metal studs, light weight specifically, and sheetrock are used in commercial environments. You do not construct a skeleton with light weight studs they simply cannot support their own weight with the additional loads. You must always, always have a rigid either red iron or concrete structure to which you attache the light weight metal studs to. This applies to the top or uppermost portion of the metal wall assemblies that are by code and for good reason, attached directly to the upper concrete deck with metal struts.

This is a coupled system.

Two is that when these assemblies are tested it is more for fire rating than any thing else. A 2 layer (one layer either side) 5/8 x rated sheathed assembly will develop a one hour fire rated wall assembly. This saves lives. The by product of a 45 to 49 STC(Human listening levels NOT musical consideration which is TL) meets the criteria of the standard set for isolation between people. People...not musical influence.

The deflection ability of any assembly, wall or ceiling or floor is always taken into consideration because the incorrect loading with all seismic events, live and dead loading taken into account, and all total weights of ALL materials involved can produce a catastrophic failure.

This means a collapse of a structure or partial collapse due to listening to people that think out loud on the Internet with NO strength in the fields we are discussing.

As usual - you completely missed the point without considering what I said - so I will ask the question plainly.
When is the sheet material playing a part in load bearing. Forgive me for not knowing the correct engineering terms, as unlike you, I am not skilled in building code or materials analysis - just a curious observer.

My understanding of resistance to bending comes from the point of compression and tension - so if you align vertical sheets of drywall, or other sheet material into a thicker sandwich, and these sheets are secured so that they cannot move with reference to each other, then there is resistance to flexing or bending - basic engineering properties. So this mass, attached to a lightweight stud resists warping and twisting. This layer bonding technique is established in so many engineering products that it's common.

Your assertion that a lightweight stud IS carrying the weight of the sheeting comes from where, may I ask? A vertical sheet of drywall standing on the floor exerts no force onto the studs if it is vertical, tilt even a few degrees, and until the angle is many degrees from vertical the side force is minimal. I'm obviously thinking about installing drywall when an 8x4ft sheet can easily be kept upright with one finger. A pile of these side by side exerts what force on the stud, supported on the floor?

So rather than just very unhelpfully say Wrong Answer, perhaps you could explain why my premise is mistaken - you are always so quick to insinuate how intelligent you are, and how insignificant and lacking any depth my answers are - so her is your chance. Please don't side track into anything else - just explain why you believe the stud is under load from a layer or layers secured to it vertically. That is all. Please don't be pompous, or acidic, there is no need to belittle people. Provide some physics please to explain where my premise is unsound. I am always happy to learn, but the best teachers are those willing to explain - not just rebuke, which is somewhat tiresome. You don't learn by being ticked off, or laughed at, or even having your thoughts subject to a bit of derision. You learn by facts.

Mass law, doesn't actually seem to fit here at all, does it, unless the studs were attempting to support the mass outside the CoG of the stud itself, when moments come into play. The mass being connected to the ground, removes the moment altogether?

I will start a new thread so this hijacking will end, at least in this respect, and explain to you personally where and how you are incorrect since my hair dressing analogy didn't give any clues.

The OP said in the first post: "Can I put 3 layers up safely?"

I eventually said: "But let me discuss Mass Law first. Mass Law dictates that with every doubling of mass you get a 6 dB increase in isolation. So if you have one sheet of 5/8 rock and want to increase according to mass law, you double to 2 layers of 5/8 sheetrock. If you want to get the next 6 dB increase you have to add to the existing 2 layers by 2 more layers. That is four layers."

Someone said: "Mass law, doesn't actually seem to fit here at all, does it, unless the studs were attempting to support the mass outside the CoG of the stud itself, when moments come into play. The mass being connected to the ground, removes the moment altogether?"

I stand my ground based on the math that I trust and the techniques that I attempt to help others to embrace that this is in fact correct, this is an acoustics question posited by the op.

No issue with the acoustics, just the engineering - the OP wanted to know what the stud could support, and that is where my question applies - The safety element - which is something I do and am responsible for every day simply relates to compression loading on the stud, from forces above, or the possibility of side force, causing the stud to attempt to resist the top moving laterally about the pivot point at the base.

Clearly here, if the sheet material is standing on the floor, then adding more does not impact on the stud's loading unless some shear force is applied, and the increase in mass would resist this. A structurally sound stud with a single layer of sheet material would resist something like a tripping person falling into it, while the board would probably puncture. Add a few layers for acoustics and the falling person (or wildly waved guitar headstock) would cause little damage, if any at all. Typical building construction doesn't use triangular cross bracing very often, apart from when forming the timber work. The cladding provides the bracing. A lightweight stud work inner room will have movement at the top with fairly light sideforce applied, but once just a single layer of ½" board is applied to all surfaces, the rigidity improves amazingly.

In the example the OP has posted, the real question is simply how strong the fixings are, and what the risk of punch through or crumbling is. If the wall panels do not touch the floor, the their weight is on the fixings, and the effectiveness of these to secure the panel with a downforce component as well as horizontal component is difficult to quantify. Screws, for example often have a specification for pull-out in various materials, but resistance to bending is less certain - we've all seen quite large screws bend! On the walls I'd not consider it an issue, with the panels on the floor. A lightweight stud used horizontally on the ceiling would be very different, because it would sag under it's own weight, and even more once the cladding material is applied. This is where rigidity is vital. On the walls, used vertically - the only real issue is compression resistance.

We do the same thing with metal tube work. A single vertical tube has considerable strength in compression, while the same tube used horizontally is structurally insubstantial. We then use braced two, three or four chord truss, often of thinner wall tube when we need to hang weight from it. The mechanics behind timber stud/joist construction are very similar, with timber I beams now being very popular for horizontal lighter weight, but stronger supports like joists.

Indeed, a non-acoustic wall constructed from timber studs with ⅝" plywood is amazingly strong - it's only weaker point is flex, but that is removed once two wall panels of this construction are joined at 90 degrees.