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Gyproc types for studio walls? Dynamics Plugins
Old 28th December 2010
  #1
Gear Nut
 

Gyproc types for studio walls?

Hi all, Im in Australia, just trying to figure out which Gyproc products I should buy to construct twin leaf walls and ceilings from. The data sheets don't seem to give me the info I want. Unless i'm missing something?>

any advice?

Gyprock : Home
Old 28th December 2010
  #2
Gear Addict
 

Haha, there are several types of plasterboard in Australia.

The densest type is called "sound-rated plasterboard", at 900-1000kg/m^3. It comes in 10mm and 13mm. There is a small price premium for this, plus it is harder to put screws into it unless you use a proper drywall impact driver.

The one you probably want to use is "fire-rated plasterboard" at around 800kg/m^3. Comes in 13mm and 16mm.

There are various other types, such as "standard" grade at around 650kg/m^3. (10mm, 13mm). Also, water-resistant (720kg/m^3, 10mm and 13mm). Impact-resistant (13mm). etc

Suppliers in Australia include CSR Gyprock (the largest and most well known), Boral Plasterboard, Lafarge Plasterboard and BGC (usually the cheapest and perhaps lowest quality).

Bunnings probably sells BGC but may sell the others. CSR has Gyprock Trade Centres about the place (see the web site for locations). Other brands also have various outlets.

What was the question again?
Old 28th December 2010
  #3
Gear Nut
 

thanks! you answered the question, I'll try the fire rated one you mentioned. I'll ring around heaps of stores tomorrow, I'm in melbourne if anyone can recommend some helpful or cheap stores that'd be great!
Old 28th December 2010
  #4
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Steve Honest's Avatar
 

green glue

hi there
whichever you end up using , there are some very strong arguments for bonding the sheets together using green glue, search on here for threads on it, i know of people who use the cheaper standard weight plasterbards and then bond them to get really good results and save a bit of money , though green glue is not cheap
best
steve
Old 28th December 2010
  #5
Gear Nut
 

yep thats the plan if I can afford it. twin leaf wall with 2 layers of plasterboard on each with green glue... ill see what it costs and then downgrade from there if its too much. anyone know what it often costs per metre for that style wall?
Old 28th December 2010
  #6
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Green Glue costs about an extra layer of plasterboard, in Australia. The manufacturer's recommended dosage (or coverage) is 2 tubes per 2.4x1.2m panel. That's $58 for 2.9m^2 of wall (one side of the wall). That's $20/m^2 plus installation. Installation is about $5 at a guess. (To install a layer of Fyrchek is about $10 material plus $15 labour).

If you are using double-studs then I would think very carefully before using Green Glue. The manufacturer's testing does not include back-to-back tests of double-stud walls - although heaps of back-to-back tests of other wall-framing options. I had lengthy discussions with the manufacturer going back 2 years and yet there is still no published back-to-back data for double stud walls. I think the product works remarkably well in single-stud framing and even for staggered-timber studs (but I wouldn't build a studio with those). regards double-stud walls, I am still looking forward to being convinced of the cost-effectiveness.
Old 28th December 2010
  #7
Gear Addict
 

There's a good deal of data showing the effectiveness of damping panels with decoupled framing. Staggered stud as well as double stud. The lack of test reports is because of the limited number of labs that can accurately measure partitions above STC 60 as well as frequencies below 80Hz.
Old 29th December 2010
  #8
Gear Nut
 

ah thats awkward, I had been looking at green glue data for single studded walls thinking they were double studded.

the problem is acoustics are so unpredictable by the non experts like myself, that I have no idea if going the double stud will be any advantage at all... without the green glue it is the standard. best way to do it. with the glue it could only improve??? without data its just hoping...
Old 29th December 2010
  #9
Gear Nut
 

and back to the plasterboard, any recommended/cheaper dealers of it in melbourne?
Old 29th December 2010
  #10
Gear Addict
 

Quote:
Originally Posted by Ted White View Post
There's a good deal of data showing the effectiveness of damping panels with decoupled framing. Staggered stud as well as double stud. The lack of test reports is because of the limited number of labs that can accurately measure partitions above STC 60 as well as frequencies below 80Hz.
Ted, I would love to see comparative data for double stud walls, if I could trouble you to point me at it. Most any half decent acoustic lab should do better than STC/Rw 60 and if tests are back-to-back then room volumes suitable for less than 100Hz is not so critical.

Xen, try www.buybuildingsupplies.com.au except they are likely closed at this time, along with many building materials suppliers.
Old 29th December 2010
  #11
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jhbrandt's Avatar
Quote:
Originally Posted by Sebg View Post
The densest type is called "sound-rated plasterboard", at 900-1000kg/m^3. It comes in 10mm and 13mm. There is a small price premium for this, plus it is harder to put screws into it unless you use a proper drywall impact driver.
I have not seen this data. Can you direct me to the source of the density ratings of this sound-rated plasterboard?

Xen,
I my experience, the sound-rated gypsum board costs as much as 2-3 times the cost of fire-rated. If the choice is to loose 25mm of space or $25 - we always are will in to lose 2.5cm of space.

Many times, pre-damped panels are not cost effective as are the dense sound-rated boards. - Until a more cost-effective solution presents itself, I will always recommend the type 'X' boards which are usually the fire-rated boards. These are also the same type used in generic testing and from which I will pull figures and data as necessary.

Example; I never am the first one to use a new product. I always like to wait until other people waste their money on it and get feedback and testing data to compare... I am still using Windows XP, but I'm thinking about going for Windows 7 as long as all my programs with work with it. Vista, I never liked and never installed it on any of my machines. I know what a U67 sounds like & I have never used an MXL mic... I hope you get my point.

I always get what I design when I use type 'X' board and save money too. Until someone comes up with a better product...

Cheers,
John
Old 29th December 2010
  #12
Gear Addict
 

John,

the CSR Gyprock products are:

10mm Soundchek, 9.3kg/m^2 (930)
13mm Soundchek, 13kg/m^2 (1000)

See Page A10 in the "Introduction" chapter to the CSR Red Book, downloadable on this page:
Gyprock : Design Guides - The Red Book-Fire and Acoustic Design Guide

Other brands such as Boral etc are around 900kg/m^3. So CSR would appear to have the best technology at this time (or at least the highest density).

The price premium is in comparison to the equivalent fire-rated board:

So, 16mm Fyrchek is 12.45kg/m^2 and is "listed" as $10.40/m^2.
13mm Soundchek is 13kg/m^2 and $11.50. Actual prices may vary from the list price.
Old 29th December 2010
  #13
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jhbrandt's Avatar
Great! Thanks for that...

Actually that calculates to about 1000kg/m3 for both types.

Fire rated is 12.7kg/m2 which calculates to about 800kg/m3.

Guys, Whatever gives you the most mass for the least cost is the winner.

Great news about the price difference. Thank you.
-- I think my last price check comparison was on the pre-damped panels..

Cheers,
John
Old 29th December 2010
  #14
Gear Nut
 

thanks guys! your comments have helped fill out what I needed to know.

much appreciated.
Old 29th December 2010
  #15
Gear Addict
 

Quote:
Originally Posted by Sebg View Post
Ted, I would love to see comparative data for double stud walls, if I could trouble you to point me at it.
Here's a start. Wall framing decoupled via staggered stud:





Quote:
Originally Posted by Sebg View Post
Most any half decent acoustic lab should do better than STC/Rw 60 and if tests are back-to-back then room volumes suitable for less than 100Hz is not so critical.
Well, that's not the case I'm afraid. Most labs are older and not built to give meaningful data above 60STC or below 80Hz. Flanking becomes an overwhelming consideration.

EDIT: Please let me clarify so I don't sound like an obnoxious ******. Back in the day (2004) we started reviewing data from many labs to determine where we'd be testing. Among other criteria, the flanking limit of the labs was assessed. We found that most labs started demonstrating flanking well below what their published flanking limits were. Given that we were targeting high STC /RW assemblies, it was distinctly in our best interests to be as minimally compromised by flanking as possible. This is why I have the opinion I expressed.
Old 29th December 2010
  #16
Gear Addict
 

Ted, no worries. I have to laugh as in Australia we only have 3 full-size acoustic labs for the whole of the country (used to have 4, may only have the 2 lesser ones left standing, in the not-too-distant future). There are a handful of others as well but they all have one thing or another "wrong" - eg small room volumes, test openings less than 10m^2, one room small, etc.

All our labs can "do" in excess of STC 60 quite easily, although when I have asked the technicians that run them, they haven't done the whole ISO thing where flanking limits are tested for lightweight walls, then tested for heavyweight walls, tested for walls configured built entirely in one half of the test opening, then tested for walls built with one half on each side of the vibration break etc.

Just out of curiosity, and I suppose to extend the thread hijack somewhat, does the Orfield lab have a timber-lined test opening?

Regards the test data, I have seen the data for staggered timber studs and it is impressive, as I mentioned above in one of my earlier posts. What I really want to see is comparative data for double studs. Staggered timber studs still have some coupling via the top and bottom plates (coupling that is evidently really well damped by using Green Glue). Take away that coupling and I would expect some of Green Glue's benefit to be lessened, what I want to know is by how much.
Old 30th December 2010
  #17
Gear Addict
 

Hi Sebg. The Orfield lab is decoupled double concrete walls on a floating slab. The test opening (8' x 8') is steel lined.

A damped double stud wall could exceed STC 70, and I'm not aware of any data derived from testing in a very high flanking point facility. The NRC in Canada is where one would logically go for this data.

The only double stud data I am aware of used lab-installed Green Glue that was only 7 days old when tested. A wet Green Glue test isn't exactly relevant, since the material isn't nearly fully polymerized while there's water present. If the wall was 30 days old, it would be much more relevant. The low frequency data is especially compromised when wet.

Having said that, double stud tests done at Riverbank demonstrated a 4 point gain. Again wet GG in a lab where flanking was present.

I would speculate (that's right up there with assume and opinion...) that a properly dried and damped double stud wall would hold a 6-8 point advantage over an undamped double stud wall.
Old 30th December 2010
  #18
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avare's Avatar
 

Quote:
Originally Posted by Ted White View Post
We found that most labs started demonstrating flanking well below what their published flanking limits were.
Would you expand on that please? Thanks.

Andre
Old 30th December 2010
  #19
Gear Addict
 

Should we continue this discussion in a new thread?

Ted, it is not clear from your description if each room at Orfield has its own floating slab, i.e. are there two independently floating rooms. Or is it one slab, floating on the main building structure, and both rooms are built on this one slab.

Also, are the "decoupled double concrete walls" decoupled from the slab or only from each other?
Old 30th December 2010
  #20
Gear Addict
 

Quote:
Originally Posted by avare View Post
Would you expand on that please? Thanks.

Andre
Some labs seem to shy away from either revealing their true flanking limits or sometimes indicate their flanking limits are much higher than they really are. If you ask some labs what their flanking limit is, they either "don't know" or give quite a high figure (STC80+). The problem is point at which flanking starts is a grey area, as this is frequency as well as volume dependent.

Quote:
Originally Posted by Sebg View Post
Ted, it is not clear from your description if each room at Orfield has its own floating slab, i.e. are there two independently floating rooms. Or is it one slab, floating on the main building structure, and both rooms are built on this one slab.

Also, are the "decoupled double concrete walls" decoupled from the slab or only from each other?
The walls are decoupled from each other, the walls are decoupled from the slabs, and there are two slabs, each floating and decoupled from the other slab as I recall.
Old 31st December 2010
  #21
Gear Addict
 

Andre, I will butt in and try to answer your question to Ted (if I may).

Quote:
Some labs seem to shy away from either revealing their true flanking limits or sometimes indicate their flanking limits are much higher than they really are. If you ask some labs what their flanking limit is, they either "don't know" or give quite a high figure (STC80+). The problem is point at which flanking starts is a grey area, as this is frequency as well as volume dependent.
The ISO Standard 140-1 (and other ISO Standards as well - what a rort that bureaucracy has become) specifies very clearly that the flanking limit for a laboratory must be determined for the various types of walls that will be tested - lightweight panels, lightweight masonry, heavyweight masonry.

Also, since there is a vibration break between the two test chambers, the flanking limit will also depend on whether the test specimen is on one side or installed over both sides of the vibration break.

Very few laboratories have bothered to do all this comprehensive testing in a systematic way - although over time they should have built up a reasonable test portfolio and should be able to glean from that.

ISO 140-1 states that the Test Report should include the appropriate flanking limit for the type of wall being tested. Most laboratories are just a bit lazy and only quote the "maximum" TL ever recorded, which is not necessarily appropriate to the wall being tested. Hence, this would explain Ted's statement that "We found that most labs started demonstrating flanking well below what their published flanking limits were." This is probably because the published flanking limits are the "maximum TL ever", NOT the appropriate ones.

I would love to link you a copy of the Standard but for some reason we have to pay through the nose for the privilege of reading it. Considering there are 30 or maybe by now even 40 ISO Standards that describe or relate to acoustic testing methodologies and that each Standard is over $100... (every year new Test Standards are added. I could perhaps swallow it if they were $30-$40 each but at 3x that price, ridiculous does not even describe the situation. And professionals in the field are being extorted for this money as they have to know what the Standards say).
Old 1st January 2011
  #22
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avare's Avatar
 

Quote:
Originally Posted by Sebg View Post
Andre, I will butt in and try to answer your question to Ted (if I may).

The ISO Standard 140-1 (and other ISO Standards as well - what a rort that bureaucracy has become) specifies very clearly that the flanking limit for a laboratory must be determined for the various types of walls that will be tested - lightweight panels, lightweight masonry, heavyweight masonry.

Also, since there is a vibration break between the two test chambers, the flanking limit will also depend on whether the test specimen is on one side or installed over both sides of the vibration break.

Very few laboratories have bothered to do all this comprehensive testing in a systematic way - although over time they should have built up a reasonable test portfolio and should be able to glean from that.
ISO 140-1 states that the Test Report should include the appropriate flanking limit for the type of wall being tested. Most laboratories are just a bit lazy and only quote the "maximum" TL ever recorded, which is not necessarily appropriate to the wall being tested. Hence, this would explain Ted's statement that "We found that most labs started demonstrating flanking well below what their published flanking limits were." This is probably because the published flanking limits are the "maximum TL ever", NOT the appropriate ones.

I would love to link you a copy of the Standard but for some reason we have to pay through the nose for the privilege of reading it. Considering there are 30 or maybe by now even 40 ISO Standards that describe or relate to acoustic testing methodologies and that each Standard is over $100... (every year new Test Standards are added. I could perhaps swallow it if they were $30-$40 each but at 3x that price, ridiculous does not even describe the situation. And professionals in the field are being extorted for this money as they have to know what the Standards say).
The ASTM spec is E90. Same bureaucratic mess, different letters. My bolding in the quote is what I am curious about. Labs not doing what they are supposed to do to commision their chambers.

Andre
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