Green glue and denim insulation

[django1]

We don't have Green Glue here in Quebec but I should be able to order it. Is it all they say it is?

Also, anyone try this denim insulation? They claim it "offers superior acoustic performance when compared to traditional insulations, up to a 36% increase in sound absorption!" but don't offer up any numbers.

[dguarnaccia]

I used denim insulation on the wall I built to close off my home theater room, and it indeed aborbs a great deal of sound. I can do measurements when I get home, but I can be watching a movie full tilt, and you can barely hear it outside the room...and it wasn't all that more expesive than normal insulation.

[Steve_vai_rules]

We don't have Green Glue here in Quebec but I should be able to order it. Is it all they say it is?

Also, anyone try this denim insulation? They claim it "offers superior acoustic performance when compared to traditional insulations, up to a 36% increase in sound absorption!" but don't offer up any numbers.

the studio i work at used something very similar to green glue, different manufacturer but similar specs from what i recall. And it performs very well. i dont know the exact figures for our level of isolation but they are top class. I can talk to the studio manager and see what info i can get (sometimes its hard though, they like to be secretive about what they have done to get some of their performance numbers, at least that is my case dealing with various studios..).. green glue by itself doesnt do a whole lot, its the fact that it decouples the interior drywall sheet from the exterior one and absorbs the energy of sound waves hitting that external sheet and converts the mechanical pushing and pulling forces of the sound into heat.

havent seen what the denim stuff is all about but i have used roxul before:

http://www.roxul.com/home

http://www.roxul.com/residential/residential+technical+data

There may be a white paper or something that the denim guys have.


http://www.greenglue.ca/ for canadian orders of green glue

http://www.quietrock.com/soundproof-...ping-glue.html an alternative to green glue. and cheaper

another alternative http://www.supressproducts.com/products.php

http://www.dryco.ca/ and more.


Matt

[Steve_vai_rules]

http://inpursuitofsilence.com/2010/04/29/getting-unstuck-from-green-glue-the-limitations-of-todays-soundproofing-magic-the-perennial-noise-of-marketing/

also of note:

most of the adhesives are more effective at higher frequency sounds.. but low frequency sounds can still pass through.. the best way to defeat low frequency sounds is with solid rigid strong and dense walls..

Matt

[django1]

Thanks for the info guys! I know about Roxul, just wondering how the denim stuff compares. Can't find any numbers on the stuff.

[dvenardos]

When I was trying to get a source for Roxul in California I found out that it wasn't approved in California and denim was my only choice. I was really pretty sold on Roxul, lots of good stuff about it.

[Steve_vai_rules]

Thanks for the info guys! I know about Roxul, just wondering how the denim stuff compares. Can't find any numbers on the stuff.

short of emailing the company i couldn't find anything either... which may be a good option for you.. get the stc ratings and make sure they tell you them for different frequencies so you can properly gauge the materials performance throughout the frequency band.


Matt

[Ted White]

Hi all,

Just wanted to clarify a few points.

Insulation IN a wall or ceiling cavity doesn't need to be anything more than standard R13 or R19 fiberglass. There's no data that shows exotic and expensive insulations perform any better. In fact, if you compare test after test, you will see a pattern that the standard "thermal" fiberglass actually has an edge in the low frequency isolation: http://www.nrc-cnrc.gc.ca/obj/irc/do...r761/ir761.pdf

Not all damping compounds work equally well. One previously mentioned damps 25% as well as another listed. Look at the available independent data.

[django1]

http://www.nrc-cnrc.gc.ca/obj/irc/doc/pubs/ir/ir761/ir761.pdf

Very thorough. Not extremely user friendly. I like this . I can't say I can't find any studies indicating one type of batt is superior to another. I would like to see some numbers on the different types of insulation. Roxul is not exotic or expensive, don't know about the denim...

[dvenardos]

For sound absorption there is really good information on acoustic panels and their performance. The same would apply when insulating in-wall. Of course, if you have the option of modifying the construction technique of the wall then you can get much better sound isolation.

For in-wall insulation I really liked roxul for its sound absorption, fire resistance, mold resistance, and non-toxic properties

[Ted White]

For sound absorption there is really good information on acoustic panels and their performance. The same would apply when insulating in-wall.

The properties ON a wall are different than IN a wall. So looking at NRC ratings for a material's performance won't translate to the performance IN the wall cavity. Two different environments.

In general in a wall or ceiling cavity, loose low/medium density insulations all operate similarly. Could be cellulose, fiberglass, mineral fiber, recycled cotton or recycled polyester. All provide the bit of resistance desired for reducing cavity resonance.

My only point was that this is an area where spending more will not get you more.

[Steve_vai_rules]

The properties ON a wall are different than IN a wall. So looking at NRC ratings for a material's performance won't translate to the performance IN the wall cavity. Two different environments.

In general in a wall or ceiling cavity, loose low/medium density insulations all operate similarly. Could be cellulose, fiberglass, mineral fiber, recycled cotton or recycled polyester. All provide the bit of resistance desired for reducing cavity resonance.

My only point was that this is an area where spending more will not get you more.

actually you are wrong about spending more not getting you more...

if proper products are purchased and implemented correctly you can get very high stc numbers (or thx rating) but those products ARE more expensive and the implementations ARE more expensive... you not only are reducing cavity resonance but you also need to absorb sound that does pass through, unless you are using solid concrete walls to kill resonance is a very very challenging thing so you need to also absorb frequencies before and after. You also need to make sure that there are no holes or gaps where the pressure waves can pass through ex. electrical outlets, ducting, bulkheads, improperly sealed corners or seams, etc. etc. etc.

you do in fact get what you pay for... sometimes though the costs dont necessarily mean a HUGE difference..


Matt

[Ted White]

My post was specific to insulation in a wall or ceiling cavity: " My only point was that this is an area where spending more will not get you more. "

Other similar sound isolation bargains:

Double stud wall framing
5/8" Drywall in layers

[django1]

Thanks for the input guys. I'm going to stick with Roxul because... I like it. It's going to be double wall, double 5/8 drywall resilient channel, that god forsaken acoustic sealant that ends up everywhere and green glue.

[Ted White]

If the framing is double stud, it is as decoupled as it's ever going to get. An excellent wall by any standard.

The resilient channel is another method to decouple. You will not gain anything by trying to further decouple an already decoupled double stud wall.

Otherwise, that's a formidable wall.