Green Glue - expensive sound proof adhesive any good?

[JimBurton]

Sound proofing home cinema room: OK I'm not going the full scientific job here, I just propose to completely line the party wall with plasterboard stuck on with Gripfill adhesive. The plan is to create several motionless air pockets behind each plasterboard panel, by applying several thick Gripfill border 'shapes' with areas sufficiently large to stick and harden without the plasterboard itself actually making any contact with the wall.
Motionless air, I seem to remember from Physics lessons, is the best thermal insulator and I'm pretty sure will do a good job audio-wise also.
However, when Gripfill hardens it is going to transmit sound directly from plasterboard to the brick wall...
I have been told that Green Glue will do the same fixing job as Gripfill but at ten times the price, due to the fact that it, apparently, does not harden but 'retains its elasticity' and thus performs as a permanent sound dampener 'reducing by 90% sound transmission through a wall'. At £170 a pop (12 tubes plus applicator gun), this could be an expensive 'try-it-and-see' trial for what could be nothing more than an extravagant manufacturer's claim.
Can I ask the Forum if anyone has experience of using this product, and whether they consider the results to justify the considerable expense?

 

[Sam Gangee]

I've never heard of "green glue" but I suspect that ordinary acrylic adhesive will cure with sufficient elasticity. Silicone rubber even more so but I'm not sure I'd want to use that on a wall. What size air gap are you aiming for? Ideally it needs to be at least 4" (100mm) and filled with rockwool or fibreglass.

 

[JimBurton]

Here you go

http://www.buygreenglue.co.uk

my 'gap' is to be the minimum possible as the room not big.

I'm thinking wall + bead of adhesive + plasterboard thus the gap will be dictated by the thickness of the bead, nothing more, no stuffing, battens or build-outs.

 

[Lucid]

Yes. It does actually work. It's like having a neoprene decoupling layer.

The trick with soundproofing it create an airtight seal while still allowing the wall to flex. Resilient channel and other decoupling methods including greenglue are good for this. Bear in mind though that air gaps around doors and windows need to be considered. Fire doors are good; heavy, high mass, in-tumescent seal helps stop air leaks. Remember too that an air-tight room still needs ventilation.

 

[Ricardus]

I've been looking at Green Glue as well for soundproofing with restricted space -I only have 50mm to work with so I'm looking at two layers of 12.5mm soundbloc / acoustic plasterboard with green glue or rubber matting like MBM5 between them.

Theres a few reviews of GreenGlue on the net though I can't be 100% sure if these are fully independant.

 

[JimBurton]

Same here, there seems so little info/feedback etc out there, you don't know if it originates from the manufacturer or their stooges.
It's surprising or revealing that there is no mention of this stuff on this whole Forum - surely some DIY-er should have tried it out by now...although it does seem ludicrously and off-put-ingly expensive...

 

[Sam Gangee]

Just for information - since it seems you don't have enough space for this - the most effective sound barrier is a 6mm thick, heavy rubber curtain suspended between the wall and the plasterboard (not touching either).

As this isn't very practical, a good compromise is to cover the wall with very light, open-cell foam rubber. This can be applied in oblong sections that are small enough to handle. Don't use dense foam!

Once that's firmly in place, glue oblong sections of thick rubber to the foam. Impact adhesive is probably the easiest solution. You can probably get rubber car mats from a car scrapyard very cheaply. Wash them and cut into rectangles then glue in place. Fill any gaps with silicone rubber. The heavier the rubber, the better.

Finish off with plasterboard. make sure there's an air gap of several mm between rubber and plasterboard.

 

[Lucid]

although it does seem ludicrously and off-put-ingly expensive...

So is proper soundproofing

Most people considering soundproofing have no idea what doing it right actually costs. They're just looking for a quick fix DIY solution. Pricing is one of those "Well I can afford to spend £100-£200" things.

Professional soundproofing can be anything up to £5000 per square metre! Domestic soundproofing rarely needs to be as effective. £50~£80 per sq m is a more appropriate budgetary figure for a worthwhile result, and less if using DIY labour. Given that Greenglue costs about £15/sq m down to under £6/sq m depending on how it is bought and used, then it's actually good value.

 

[Ricardus]

Just for information - since it seems you don't have enough space for this - the most effective sound barrier is a 6mm thick, heavy rubber curtain suspended between the wall and the plasterboard (not touching either)
-snipped-
.

I'm curious if you have any sound absorption figures for that method?

I've done a lot of searching at various points re soundproofing walls and have yet to come across anyone, pro or DIYer, who has soundproofed their walls with discarded rubber car mats sandwiched between the plasterboard and wall.

Can you be sure the rubber & open cell foam are actually doing anything or if the sound reduction is simply due to the isolation supplied by the second plasterboard wall?

 

[Ricardus]

These are two of the best vids I've come across regarding Green Glue as sound insulation.

http://www.youtube.com/watch?v=Wf6ExtPR9Xs
http://www.youtube.com/watch?v=txl4l0YIT-o

I'm pretty sure the vid from Tone1 isn't a paid shill and Matt Risinger has a load of other vids about building so unless he's a paid shill for a couple of dozen companies at the same time I'd say he was on the level.

 

[Lucid]

I can't comment on using car mats other than to wonder if the gaps would negate the benefits.

Anyway, the Rolls Royce of acoustic sound-proofing treatments IMO is Acoustiblok. Have a look at this link. It shows the product being installed in wall and in floor as a sound to heat energy barrier. It hangs loose between the joists so it can flex and that's how it does its work. http://www.acoustiblok.com/residential.php

You can search the site for their STC figures.

 

[Sam Gangee]

I can't comment on using car mats other than to wonder if the gaps would negate the benefits.

The gaps between mats wouldn't negate the benefits but they certainly need to be minimised and filled in. This is definitely the "poor man's method" but many people with noise problems are those who can't afford to live in decent accommodation, so using a really cheap substitute is the only way. It IS effective, I can say from personal experience (I was once a penniless student).

 

[hmmm maybe not]

Hi looking at this post and it being a while ago, I was wondering if Jim did use the green glue. I have a similar problem as I have only 50 mm to play with as I have door frames in the way. My wall is solid brick joining to the neighbour (who I get on well with) Unfortunately with TVs and pets both sides, things can get loud. Was looking to put plasterboard on with green glue. There is so much love it or hate it on the Internet I am not sure what to do. Not that I have many options left with such little space.

 

[Ricardus]

Apparently Green Glue doesn't work as well if you just use it to sandwich between plasterboard and the brickwork. (Disclaimer - I found one post on the entire internet from a chap who is either a GG employee or their main US distributor stating this was the case, couldn't find anybody else asking the same question)
With 50mm space to play with, you've got enough room for resilient bars (16-20mm deep) screwed directly to the wall and a double width of 12.5mm plasterboard.