Soundproofing on a budget question

howieeb

Active Member
Hey guys. I've been doing some research on soundproofing and feel like I have some grasp of the basics. Decoupling, mass, dampening, absorption. My problem is having zero diy skills and having to do this as part of a new build. So coordinating with builders, electricians etc on a busy site. I've now approached 4 companies for a quote and for our room (7m*5.1m. 2.5m high) it averages at around 16k. That's for materials and installation on walls, floor and ceiling. Not including door and plastering afterwards. So 18-20k all in. We can't afford that. What i'm struggling with now is finding a half way house - if such a thing exists - or something relatively simple/cost effective we can ask the builders to do while doing the rest of the house or have a stab at ourselves.

This is where i'm at for the minimum that's worth doing and would appreciate a sanity check. Decent density slab mineral wool for insulation, 2 layers of thick accoustic plasterboard with greenglue compound/sealant. Putty for the electrical boxes and a sturdy fire door. Someone also suggested putting chipboard down on the floor too.

Does this sound like it will have some benefit, or is it chucking money out the window? Is there anything else you would suggest? We don't mind spending money on this - we just can't spend as much as a fully fitted kitchen. Any advice/suggestions would be much appreciated.
 

AmericanAudio

Active Member
AVForums Sponsor
Depends on how far you want to go with it, but £20k should take you along way.

When we did our lounge with the intention of being a cinema as well i overlapped with double skin plasterboard and added GreenGlue as the sandwich between the two board. Along with plenty of insulation in the walls. The results are genuinely great, i did a plasterboard stud wall and the whole ceiling, works very well for its cost. Kids can hardly hear the cinema in the adjacent room ( behind stud all) and we cab hardly hear the piano even though it is against said wall.

Highly recommended.
 

howieeb

Active Member
Depends on how far you want to go with it, but £20k should take you along way.

When we did our lounge with the intention of being a cinema as well i overlapped with double skin plasterboard and added GreenGlue as the sandwich between the two board. Along with plenty of insulation in the walls. The results are genuinely great, i did a plasterboard stud wall and the whole ceiling, works very well for its cost. Kids can hardly hear the cinema in the adjacent room ( behind stud all) and we cab hardly hear the piano even though it is against said wall.

Highly recommended.

Nice one. That sounds similar to what we're thinking about. So that was just two lots of plasterboard straight onto the joists?

20k is way out of our budget btw - that's just what we've been quoted for a bells and whistles solution.
 

AmericanAudio

Active Member
AVForums Sponsor
Yes, thats all we did, first skin up and filled all the joints with GreenGlue, then we shifted the second skin across and down half a board so we got full overlap and lathered each board with a full tube (from memory) if the GG and screwed it up. Then filled all the joints again.

The only thing i regret not doing was building proper enclosures for ths Atmos and Centre ceiling speakers, because that is where we leak.

Highly recommended as an initial solution.

Something very weird about cutting out the double skin for the downlights and speakers and still being able to move the two sheets independently, whilst being stuck together, but that is how it absorbs the sound.

If you are local (Bucks / Herts) you're welcome to come and listen ( or rather, not listen) to it.
 
Last edited:

howieeb

Active Member
Yes, thats all we did, first skin up and filled all the joints with GreenGlue, then we shifted the second skin across and down half a board so we got full overlap and lathered each board with a full tube (from memory) if the GG and screwed it up. Then filled all the joints again.

The only thing i regret not doing was building proper enclosures for ths Atmos and Centre ceiling speakers, because that is where we leak.

Other that highly recommended as an initial solution.

Something very weird about cutting out the double skin for the downlights and speakers and still being able to move the two sheets independently, whilst being stuck together, but that is how it absorbs the sound.

If you are local (Bucks / Herts) you're welcome to come and listen ( or rather, not listen) to it.

Thanks mate. Appreicated. Did you do anything for the floors? Our room is on the first floor and while i'm not concerned with noise going to the rooms below it, i'd like to keep it travelling under to other rooms on the same floor.
 

Triggaaar

Distinguished Member
Hey guys. I've been doing some research on soundproofing and feel like I have some grasp of the basics. Decoupling, mass, dampening, absorption. My problem is having zero diy skills and having to do this as part of a new build. So coordinating with builders, electricians etc on a busy site. I've now approached 4 companies for a quote and for our room (7m*5.1m. 2.5m high) it averages at around 16k. That's for materials and installation on walls, floor and ceiling. Not including door and plastering afterwards. So 18-20k all in. We can't afford that.
I'll be building a room within a room - stud walls, ceiling joists, 2 layers of plasterboard and green glue - and I'll be doing the work myself. I'm really not sure how to advise someone who doesn't have the time or DIY skills to do likewise, because I imagine my job would also be very expensive if I paid a good company to do it. Is it possible you can improve your DIY skills, or find someone who knows what they're doing to help?

Where are you based?
 

kungfuman

Active Member
In my old cinema room, I had used insulation blocks between joists and then two layers of acoustic plaster boards with green glue. the impact was reasonable although not perfect. i could still disturb my daughters sleep when listening loudish (-10db on amp) which is a room on other side of house. when i moved my set up downstairs, i went a bit further with soundproofing by using a denser and thicker insulation blocks, used genie clips with furring channels to decouple and 2 sheets plasterboard with green glue. this is much improved now and i can listen loud at night (8-10db on amp) and it is barely noticeable in my daughters room. i also stuffed lots of insulation between the voids of the floor joists to help stop sound travel. definitely recommend decoupling the plasterboard if you can by using resilient channels, genie clips, etc.

i did most of the work myself and i would say i have basic diy experience but it did take a lot of time and effort. the finishing is also not perfect but being in a dark cinema room, it's not noticeable.
 

xar

Well-known Member
I would be very wary of any builders doing this type of work properly. I had similar quotes but on detailed questions from myself, they didn’t really know what they were doing. They just quoted double for ‘double’ the effort.

I ended up using these guys to retrofit my room and it made the world of difference: Rosewood sound proofing

They are based around Edinburgh so probably not suitable, be worth asking if they can recommend someone more local / give advice. My room originally had double plasterboard and green glue on all walls, ceiling and floor (wood on the floor obviously), with the ceiling and walls decoupled, with 75mm rockwool. But to be honest it was rubbish. My wife was always texting me from the house (my room is a detached garage) to tell me to turn it down.

They ended up using 2 layer of acoustic plasterboard (15mm and 12.5mm for different frequencies) with acoustic rubber sheets in between, 100mm rw5 (extra dense), double doors, with both being fitted with acoustic rubber sheets between some plywood.

My honest view is that doing something ‘cheap’ is probably not going to be much use, but be a hassle and cost you a fair bit.
 

xar

Well-known Member
In my old cinema room, I had used insulation blocks between joists and then two layers of acoustic plaster boards with green glue. the impact was reasonable although not perfect. i could still disturb my daughters sleep when listening loudish (-10db on amp) which is a room on other side of house. when i moved my set up downstairs, i went a bit further with soundproofing by using a denser and thicker insulation blocks, used genie clips with furring channels to decouple and 2 sheets plasterboard with green glue. this is much improved now and i can listen loud at night (8-10db on amp) and it is barely noticeable in my daughters room. i also stuffed lots of insulation between the voids of the floor joists to help stop sound travel. definitely recommend decoupling the plasterboard if you can by using resilient channels, genie clips, etc.

i did most of the work myself and i would say i have basic diy experience but it did take a lot of time and effort. the finishing is also not perfect but being in a dark cinema room, it's not noticeable.
I would suggest (as per this post) that mass, tight fit in all voids, and any decoupling is your best bet. Sound is like water, in that it will escape through any hole you leave for it.
 

kungfuman

Active Member
Also don’t forgot about the entry doors which will be the next weak point. I went with two doors, sealed all around and with an air gap. This has made another decent improvement.
 

Triggaaar

Distinguished Member
when i moved my set up downstairs, i went a bit further with soundproofing by using a denser and thicker insulation blocks, used genie clips with furring channels to decouple and 2 sheets plasterboard with green glue. this is much improved now and i can listen loud at night (8-10db on amp) and it is barely noticeable in my daughters room.
Sounds good. Do you have any drawings or photos to show what you did? Although I'm interested in genie clips and channels, I'm not confident of getting it all right.
 

Triggaaar

Distinguished Member
I would be very wary of any builders doing this type of work properly. I had similar quotes but on detailed questions from myself, they didn’t really know what they were doing. They just quoted double for ‘double’ the effort.
Unfortunately I would say that's good advice. Even on building a basic extension, I find that builders with many years experience aren't very good with heat insulation, and they'd be even worse with sound.

My room originally had double plasterboard and green glue on all walls, ceiling and floor (wood on the floor obviously), with the ceiling and walls decoupled, with 75mm rockwool. But to be honest it was rubbish.
Why do you think it wasn't good? Do you think the spec was wrong, or could the installation have been below par?

They ended up using 2 layer of acoustic plasterboard (15mm and 12.5mm for different frequencies) with acoustic rubber sheets in between, 100mm rw5 (extra dense), double doors, with both being fitted with acoustic rubber sheets between some plywood.
Do you have a link to the rubber sheets?
 

xar

Well-known Member
Why do you think it wasn't good? Do you think the spec was wrong, or could the installation have been below par?
I primarily meant that the green glue wasn’t that effective. I felt for the expense and effort, it wasn’t worth it. I used it as it saves space, but thicker and heavier rockwool fitted tight is much better (albeit it does take up more space)

I don’t know the exact brand of acoustic rubber, but it was very similar to this:


I also used copious amount of acoustic sealant:

 

Triggaaar

Distinguished Member
I primarily meant that the green glue wasn’t that effective. I felt for the expense and effort, it wasn’t worth it. I used it as it saves space, but thicker and heavier rockwool fitted tight is much better (albeit it does take up more space)
Well they're for different jobs.

I don’t know the exact brand of acoustic rubber, but it was very similar to this:
Thanks, I'll take a look.

I also used copious amount of acoustic sealant:
The second time around?
 

kungfuman

Active Member

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xar

Well-known Member
Well they're for different jobs.
No, they aren’t. Green glue is supposed to be an alternative option to save space with comparable results. I.e. you can use less mass depth plus green glue for the same result as more mass / depth. My experience is that this is not true, and more mass / depth is materially better.

I used the sealant both times.
 

Triggaaar

Distinguished Member
No, they aren’t. Green glue is supposed to be an alternative option to save space with comparable results. I.e. you can use less mass depth plus green glue for the same result as more mass / depth. My experience is that this is not true, and more mass / depth is materially better.
That doesn't match my understanding of soundproofing. My understanding is that you should ideally use a combination of Decoupling, Adding Mass, Damping, and Absorbing. The green glue is for damping, and should be done as well as adding fibreglass (which can add mass and absorb), not instead of.
 

xar

Well-known Member
That doesn't match my understanding of soundproofing. My understanding is that you should ideally use a combination of Decoupling, Adding Mass, Damping, and Absorbing. The green glue is for damping, and should be done as well as adding fibreglass (which can add mass and absorb), not instead of.
I didn't say Green Glue was instead of mass, but it is touted as an alternative to adding additional mass (see the umpteen case studies on their website).

The majority of these posts have the OP stating they are going with 2 layers of acoustic plasterboard and Green Glue, plus 50mm of rockwool. I did exactly this (as advised by other members on this forum at the time when I built the room, and reading all the same advice/case studies I assume you are), and found it to be poor, so I try to warn others about doing the same. Its expensive, messy, and not that good.

Hence I now advise (based on 3 different room builds, one as per above, the reworked version of that room with more mass and rubber matting, and more recently a 50% extension to the same room using the same technique, undertaken purely by myself), that additional mass, tight fitting/no air gaps, rubber matting, 2 layers of acoustic plasterboard of different thicknesses, and a double door should be the priority items. i.e. mass and no air gaps. Everything else is just a bonus.
 

howieeb

Active Member
My honest view is that doing something ‘cheap’ is probably not going to be much use, but be a hassle and cost you a fair bit.

That's what i'm worried about. A few questions if you get a min.

You mentioned you decoupled your walls/ceiling - what system did you use?
It sounds like the main change you made was using rubber matting rather than green glue and adding an extra door - is that about right? Are you happy with it now?

Hence I now advise (based on 3 different room builds, one as per above, the reworked version of that room with more mass and rubber matting, and more recently a 50% extension to the same room using the same technique, undertaken purely by myself), that additional mass, tight fitting/no air gaps, rubber matting, 2 layers of acoustic plasterboard of different thicknesses, and a double door should be the priority items. i.e. mass and no air gaps. Everything else is just a bonus.

Noted. I'm now leaning towards decent insulation, decoupled walls, two layers of plasterboard and some kind of mat (if budget allows) or green glue between them. I'm also going to ask the architectes what the cost would be in having 4 walls built inside the existing room and then decouple the ceiling. The floor i'm thinking insulation and as much mass as can be added.

here are the instructions for genie clips:


i've also attached some pictures when i was making one of the side walls.

Looking good, kungfuman. Did you find them pretty straight forward to install?
 

xar

Well-known Member
I am happy with my room now thanks. No complaints from the missus at least...

Note that this is a tricky subject. A lot depends on how loud and how low your bass is going to go, as you can go a bit crazy with this stuff. What worked for me, and is probably the best bang for you buck/ relatively easy would be:

- internal stud wall not touching existing one
- fill with 100mm of RW5 rockwool making sure no gaps - don’t skimp on quality fibreglass
- 2 x layers of acoustic plasterboard 15mm and 12.5mm, ideally with rubber matting in between
- fire door with an extra layer or acoustic matting and plywood, or 2 x fire doors with an air gap

Note that this required circa 150mm of space from each wall, so the room shrank by 30cm on both horizontals, and 15cm on the ceiling. You might not have that much space to waste, and this is where the genie clips become appealing. I do stand by rubber matting being much more effective than green glue however.

Decoupling: I used a room with a room, so the internal studs for the new room didn’t touch the existing wall. The bottom of the stud wall sat on rubber strips.

The ceiling used resilient channels, but there were and absolute nightmare to try and get 2 layers of plasterboard onto - I think I broke 4 panels trying to do it (like these:Libra Resilient Bar 3000mm). Genie clips are probably easier to work with, but if I did it again I wouldn’t bother be would just put rubber strips on the rafters first.

In addition, I used surface mounted plugs point to minimise holes, and ran all cabling internal to the room on a lowered ceiling round the edges, which also hosts the lights. This means the room is sealed.

Note that is you could spend a lot of time doing all this, then cut holes for in wall / ceiling speakers, and it’s pretty much for nothing. The sound will get out any hole you leave for it, so focus on sealing the room as much as anything else. I would do that before rubber matting / resilient channels etc
 

xar

Well-known Member
This stuff:


If you look at the link it has a diagram showing the application options.
 

Triggaaar

Distinguished Member
I didn't say Green Glue was instead of mass, but it is touted as an alternative to adding additional mass (see the umpteen case studies on their website).
Plenty of people here and across the pond have built with green glue doing the damping part of their spec, and found it to work well. It obviously didn't work well for you, but it's difficult to know if that's because of the green glue, or because of the other things you mention:

Hence I now advise (based on 3 different room builds, one as per above, the reworked version of that room with more mass and rubber matting, and more recently a 50% extension to the same room using the same technique, undertaken purely by myself), that additional mass, tight fitting/no air gaps, rubber matting, 2 layers of acoustic plasterboard of different thicknesses, and a double door should be the priority items. i.e. mass and no air gaps.
So your more recent builds have been more successful, but they've also had additional mass, tight fitting/no air gaps, and a double door. I don't doubt what has and hasn't worked for you, but equally I have seen independent people build successfully with green glue (and isolation, additional mass, tight fitting/no air gaps) in place of the rubber. That includes people building professional studios and running tests between green glue and other products.

For my build I'd need about 56 linear metres of their 1.25m wide rubber sheeting. That would work out at £1,381 (if using the 3mm stuff you linked to, but maybe the thinner stuff is enough?). Green glue would be more like £587. That's a big difference. Obviously worth it if one works and the other doesn't, but the other testimonials suggest the green glue does work.
This stuff:


If you look at the link it has a diagram showing the application options.
Thanks. I think I'll try the 70mm under my stud walls. I don't know if it's worth putting them between the walls and new ceiling joists or not, as I don't really need to isolate them from each other.
 

xar

Well-known Member
So your more recent builds have been more successful, but they've also had additional mass, tight fitting/no air gaps, and a double door. I don't doubt what has and hasn't worked for you, but equally I have seen independent people build successfully with green glue (and isolation, additional mass, tight fitting/no air gaps) in place of the rubber. That includes people building professional studios and running tests between green glue and other products.
The original build had no air gaps and a double door (the same). The difference is the rubber matting and the additional mass, and that was installed by a professional company that does sound studios in the UK and Europe, but more importantly, it worked far far better. Thats the key point I am trying to get across.

To be honest I am not looking to debate this any further. This thread goes the same as most of the others, whereby someone with no actual experience points at the studies and says 'look, it worked for these guys AND it was cheaper, so thats what I am doing', which I am sure works perfectly well for many, but it didn't for me so I had to rip it out and start again and that cost me more. But like I noted above, as I run my equipment loud and have very powerful dual subs.
 

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