gypsum / Bubblewrap / gypsum ???

[jhbrandt]

Daniel,

Green glue is the only thing that makes an effective sandwich with gypsum board. Don't waste your money or time with anything else. - By the way, I don't sell the stuff & only a few of my studio designs use it.

The bottom line is; what are you trying to accomplish? How much isolation do you need? Get us a decibel figure and we'll show you how to obtain that STL in a partition assembly.

Cheers,
John

[ScottTunes]

+1 for Green Glue.

I cheated, and used GE's "50 year" caulk. Not sure how much better Green Glue is (IF it is), but it's been tested in this situation, and GE's caulk has not (that I know of anyway).

[Daniel Nel]

Hello thanks for the quick reply , i guess i should have given more info for the specific application , but i thought i,ll keep the question simple regarding 'something to sandwich between gypsum'

Regarding GREEN GLUE : I,m in South Africa and i never considered it as a option , but i have found a supplier nearby and i,ll get quotes in the next week...!!

I also saw this
Sound Block Sheet | Damping Sheet | T-Max

The BUBBLE WRAP just made sense and thought some others have considered using it .

What i got..!!!...Existing freestanding garage with brick wall's and roof, but no ceiling that i,d like to use as a rehearsal / practice room ,
Isolated enough for Full Band without disturbing the neighbors , which is about 10m away , also to block penetrating traffic noise about 25m away.

The space is a single garage (5m x 3m) and (1.5m x 2.8) area that i can use for a vocal booth.


THE BUDGET ...!

I,m on a short term small budget , it's not permanent.
And i,m prepared to go the full-monty when in need , so i thought i,ll build the dry-wall / sound roofing in layers when more cash becomes available.

I,ve looked at STC Ratings

What i think i need...
---Brick wall / metal stud + air / gypsum x2 / metal stud + rockwool / gypsum x2 -- -

I would do it in stages.
The idea is to create a space for low noise first (which is pleasing to the eye )and then increase the wall layers when the demand gets bigger.

( starting with step #3 if the startup budget is enough)
Starting with the brickwall , moving to interior

1. Metal studs / single layer gypsum
2 (sandwich something between ) + layer gypsum
3 metal studs / rockwool / single layer gypsum
4 (sandwich something between ) + layer gypsum.
and
5 acoustic treatment

[tarnationsauce]

Originally Posted by tifftunes

+1 for Green Glue.

I cheated, and used GE's "50 year" caulk. Not sure how much better Green Glue is (IF it is), but it's been tested in this situation, and GE's caulk has not (that I know of anyway).

GE caulk and GG are totally and completely different. Not to say the GE caulk won't have some effect on decoupling. As you said GE caulk hasn't been tested. That 50 year caulk is great at what it is supposed to do: seal cracks and fill small holes. Good stuff for studio construction.

Construction adhesive vs GG is 18 STC difference. that is very significant. I have a feeling Caulk is closer to the adhesive than to the GG, but only a real scientific test could tell us that answer.

Green Glue not only helps decouple but also it mostly dampens resonances.
Dried Green Glue is a very gooey and soft substance, like soft, fresh bubblegum. It is so pliable and sticky you could pull some off and stick it back on.

As for the Bubblewrap the OP is suggesting, I think it would deteriorate in only a couple years and for the work involved would only be a very tiny help if any. And I bet a building inspector would not approve at all.

[gouge]

what impressed me about green glue was it's low freq figures. i think if used in typical studio type construction where you already have mechanical decoupling as a fundmental part of the detailing GG just gives you that little bit better attenuation of the lower freq.

well that's how i interpreted the data.

[DanDan]

The layer of fibre in the void between the two leaves is intended to dampen resonance in that chamber. It may also have a slight damping effect on the actual leaves if it is touching them lightly. I cannot see bubble wrap doing that.
Fibreglass and Rockwool are the most frequent for a good reason. Best and cheapest, and fireproof.
DD

[Daniel Nel]

Hi.

Thanks for all the input regarding Bubble-wrap.
Its clearly not a winner. Case Closed


Anyways , found some supplies at Unlimited Building Supplies
and they use something called , IM24 Eneremlite 24)
http://www.europair-africa.com/downloads/insulation.pdf

Re: Green Glue , they dont stock it and the other suppliers dont answer the phone , will try later.

Now to consider the layer options ?? Should i start a new thread to double layer , and which layer first..??

[jhbrandt]

No worries...

Standard building materials are your friend. Use type 'X' gypsum board which is usually called 'fire rated' and regular thermal building insulation in the wall cavities. If you need more mass to get the transmission loss you require, simply add more layers of the type 'X' and use thicker stuff. - and/or increase the air space...

Cheers,
John

[xaMdaM]

What i think i need...
---Brick wall / metal stud + air / gypsum x2 / metal stud + rockwool / gypsum x2 -- -

OOOOPS...

Me thinks this was an overlooked point... (Except by DanDan)

1) Brick wall
2) metal stud
3) air
4) gypsum x2
5) metal stud
6) rockwool
7) gypsum x2

The assembly as you describe it, would be a triple leaf assembly, which will LOWER the sound proofing and be rather costly when it doesn't have to be.

I would propose you explore it this way;

1) Brick wall
2) air
3) 2x6 wood stud (Your equiv)
4) R-19 pink fluffy
5) 5/8" to 3/4" OSB or Plywood (Your equiv thickness)
6) Type x gypsum x2 (with green glue)

or

6) Type X gypsum x3/x4

A couple of points of clarification;
Since you have no ceiling to attach any resilient channel to, you will need to place a joist/ceiling assembly on top of your new walls. AFAIK, you would need to go from the thinner residential metal studs to the much more costly thicker and larger (2x6) commercial metal studs to handle the mass of a double or triple layer type-x gypsum ceiling. So, switching to an equivalent 2x6 stud will probably be cheaper.

Adding OSB/plywood or some other sheetgood to the surface of the studs does a coupla' good things that many overlook... It adds rigidity to the stud assembly, and lowers the overall f0, as it also adds significant mass. The real bonus is that you don't have to worry about missing a stud when you are screwing the gypsum to the studs... especially after the first layer. From a real world experience standpoint, that alone is worth the cost of admission.

Green Glue doesn't just increase the low frequency TL. It increases the overall TL... to the tune of adding the equivalent of just over 2 additional layers of gypsum. If you cannot get real Green Glue, I wouldn't bother with any of the other products that claim to be "just as good". To date, none of the other products have any testing done that is reliable; e.g. faked numbers. So, if you can't get Green Glue, I'd put up two layers of type-x and set up a drum kit and bass amp... crank it up and see what you get. If it's not enough, add a layer of gypsum, lather, rinse, repeat; until you get enough isolation that you're satisfied with the results. (There was a guy over in England named Paul Woodlock, who designed his Control room to have 1 layer of 3/4" MDF and SEVEN layers of type-x gypsum.... but I can guarantee you, finding screws that long was pretty expensive!)

The concept of hanging MLV between the gypsum, while well intentioned, is erroneous and a serious waste of money. The correct way to throw that money away is to hang the MLV product directly on the stud, BEHIND the gypsum. But you MUST hang it correctly; not too loose, not too tight, but just right. The original concept of hanging MLV on the stud face was to dampen any vibrations that occur within the stud cavity from the vibration of the gypsum. Therein lies the rub. What is the correct tension in which to place the MLV? Good luck with that calculation, much less the method of tensioning it to that value.

By going to a 2x6 wood stud and filling the cavity with the equivalent R-19 (6" thick) insulation, you are actually negating the need for what the MLV could possibly bring to the table in terms of TL/STC.

Just some things to consider....

[gouge]

hi xamdam,

i can't say i completely agree with your comments there.

you are comparing green glue on coupled wall systems. if you compare the GG test results for non coupled walls you will see decoupling the internal linings from the studs does the same as using green glue on a coupled wall. other than better low freq TL.

i have searched for test data of GG on decoupled wall systems and have not found anything substantial. i suspect this is because decoupling the walls achieves the same outcome.

GG is not cheap. neither are resilient mounts. i guess like most things it comes down to a cost analysis.

also, plasterboard gives a bracing capacity on a wall. both plasterboard and plywood and compressed FC can be used as bracing. i'd prefer to see the plywood in your layup go on the inside face of the wall. that would improve the RT60 results.

Daniel,

standard brickveener wall with 1 layer of 10mm high density board on the inside face and 100mm insulation to the stud wall, a 50mm cavity and an overall makeup of 260mm approx will give you about Rw (STC) 60

that's more than good enough for stand alone garage for a jamming space and is based on a 110 brick. if your garage is 230 brick it will be even higher. but it depends on a few detail items lie wall roof connection.

also by adding a second layer of 10mm and a thicker batt you will push it up to Rw (STC) 65.

ceiling i'd do isolated battens with 2 layers of high density board and 100mm insulation. that will get you about Rw 55 (STC).

your problem is going to be doors and windows. no point spending dollars upgrading walls if the windows are only Rw35!

but my disclaimer is this all depends on how close your garage is to your neghbours??????

so really you need to draw up a plan and note the existing construction type and thicknesses.

[avare]

Originally Posted by gouge

i have searched for test data of GG on decoupled wall systems and have not found anything substantial. i suspect this is because decoupling the walls achieves the same outcome.

That is my understanding also.

Andre

[Daniel Nel]

Hi Thanks for all the input..!


@John...i,ll check on the Gypsum that its fireproof.

@xaMdaM..Thanks for suggesting OSB / Plywood.

It makes a whole lot of sense , specially when it comes to adding extra gypsum if i need more mass. Also finding the channel is gonna be a nightmare if i decide to add another metal stud.

Regarding Green Glue : Still cant find the stuff in South-Africa , I,ll just add some extra layers . Gonna be easier without Green Glue if i need to dismantle someday and re-use the OBS/Plywood

ATM i think this will be a good option to layer the walls for starters
Brickwall / Metal stud (or wood) + rockwool / OBS

for Ceiling
Roof truss or Joist / 2x4wood + Rockwool / OBS

But i,m on my way to take some pictures and measurements , perhaps a sketch-up or two.


I,ll start a new thread when i got picture and solid info on measurements...!

[xaMdaM]

Daniel,

Regular "pink fluffy" fiberglass wall/ceiling insulation in the stud bay's and ceiling joists will serve you better than ANY rigid insulation.

I don't have the numbers at my fingertips at the moment, but it is a significant percentage difference between regular fiberglass and any rigid insulation.

The biggest factor in the difference is the amount of air displacement within the stud cavity, with the nod going to regular fiberglass.

[edit]
Just noticed sumpin' kinda' scary...

Your ceiling joists are going to need to be quite a bit beefier than a 2x4, and will be dictated by the span. Hopefully someone with greater engineering background will jump in and correct me, but to span your typical 16' room you'll need at least a 2x10, or possibly a 2x12, depending on how much gypsum you plan on using.

[Dave Davis]

asbestos, lead, asbestos.

[Ted White]

You are not going to get a similar damping effect by decoupling. Decoupling is not damping. Damping is very useful in a decoupled environment.




Panel resonance and the resulting transmission is still a factor even in a decoupled environment.

[Daniel Nel]

New Thread

Pimp my Garage

[Dange]

By the look of the pictures in your 'pimp my garage' thread, the weakest points will be the ceiling/roof and the large door. Improving the brick walls will do little unless the ceiling/roof and door are up to the same insulation level as the brick walls on their own. Those brick walls look pretty thick and solid, so I'd concentrate your efforts on the roof and doors. How much are you allowed to alter the garage, is bricking up the large door viable?

[Dange]

Also on decoupling, using resilient bars/channels to decouple the layers of plasterboard or using green glue between layers are both achieving the same thing, a change of the coincidence dip frequency and the overall stiffness of the panel. They do it in slightly different ways though.

Resilient bars/channels effect the mounting conditions and hence stiffness of panel. (also note that two thin layers are better than one thick layer as the panels 'rub' against each other and this friction causes losses)

Green Glue between the layers is contrained layer damping, one layer contrains the other layer via the compound between.



Also none have 'active' damping. This is a misuse of the term. Active implies feedback control involving electrical circuits or similar. Some cars have active damping suspension, this is where the viscosity of the hydralic fluid involved in damping is 'actively' changed by a magnetic field in response to road conditions. The hydralic fluid has iron particles in it.

[Daniel Nel]

Hi Dange.

Cool for giving advice on progression.

Sure , the ceiling is my biggest concern at the moment.
and i dont think the landlord will allow me bricking up the big door , i,ll have to panel it off.

I,m gonna ceiling the small 1,5m x 2.8m room and see how well my building skills goes and take it from there .
I only need that room for vocals and a small mixing space for beats.

I,ll plan the main room from there on.

[Ted White]

Originally Posted by Dange

Also on decoupling, using resilient bars/channels to decouple the layers of plasterboard or using green glue between layers are both achieving the same thing, a change of the coincidence dip frequency and the overall stiffness of the panel. They do it in slightly different ways though.

Resilient bars/channels effect the mounting conditions and hence stiffness of panel. (also note that two thin layers are better than one thick layer as the panels 'rub' against each other and this friction causes losses)

Just to clarify a couple of those points. Hope that's OK.

Decoupling is not damping. Damping does not change the coincidence point of the drywall panel. Coincidence is defined by the density and thickness of the leaf. Damping does not change this, nor does decoupling. The panel density and thickness does not change as a result of damping or decoupling.

Damping reduces the measurable resonance-type behavior at coincidence through the low frequency MAM resonance. We see this is a flatting of the coincidence point(s) on a TL plot.

The primary benefit of decoupling is the drop in the frequency at which the resultant system demonstrates low frequency MAM resonance. This allows us to better control a broader frequency range.

[Dange]

Originally Posted by Ted White

Hope that's OK

No problem, I'm wrong, You're right Ted. Someone who actually knows what's going on at a physical level with the 'soundproofing' materials they sell. Wish we had that here......

The resilient bars decoupling shifting the coincidence frequency was something a senior acoustic consultant once told me, I took it on merit...seems that was a mistake! I've looked into it. Critical frequency, fc, above which the coincidence dip can occur, is defined by

fc= c^2/(1.8*h*vL)

where c=speed of sound in air, h=panel thickness, vL is velocity of longditudinal waves in the panel material.

With the addition of res bars or GG, neither c, h, vL change. It's the same panel(s) made of the same material....

Damping not shifting coincidence dip frequency is kind of obvious.....if I thought about it

Still 'active damping'........c'mon

--------------------------------------------------------------------------


Was this what people were looking for earlier....GG vs GG on resilient strips - Noise Reduction Systems | Green Glue vs. Resilient Channel

[gouge]

not wanting to get into an argument about the maths or offend the gg experts but we are not really dealing with my comment by comparing apples with apples.

what i said was that gg is comparable to isolation (resilient mounts or 2 walls) but i thought that gg gave a better attenuation in the lower freq. i was keen to see test data of double wall construction with green glue as i have not been able to find anything to date.

the test results above look good but are not comparing resilient mount versus GG.

Dange's link does compare resilient mount versus GG to both sides and the difference is only 1db. when you look at the cost table lower down the example only indicates gg to one side as a cost comparison. so gg to both sides would cost more than resilient mounts for only 1db gain.

not that that's a bad thing as sometimes resilient mounts are the way to go and sometimes GG is the way to go and sometimes both. depends on construction methods, existing walls etc.

personally i go with both isolation of frame plus GG as i believe the combination gives better results. but i'd love to see some data of double wall tests with and without GG to confirm that.

[Daniel Nel]

Hi guys.

First thing on my list is the 2.8m x 1.5m ceiling.

Would it be a good idea to use this Pine ShutterPly.
I,m thinking to use the 21mm board .

PG Bison - Plywood | Cupboards | Shelves | Chipboard | Melamine | Masonite | Formica | Bison | Plywood | Blackboard

and then if i need any more isolation i,ll add a extra layer of Gypsum


This is how the roof looks like and the little room




One or two questions


1 : It get's hot in the summer , would u guys recommend normal fluffy pink or proper Rockwool ?

2 : The roof is at a angle. Would u decouple the ceiling from the roof structure and level with joists bracketed to the walls
and screw the Pine Shutterbaord against that..??

3 : I,m thinking to use the 21mm , its only for a small mixing room or vocal booth.
Is 21mm enough or overkill..??

like this for example , the first ceiling that i,m gonna tackle first is 2.8m 1.5m.