Another Soundproofing thread

Nayfne

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Ok, so having spent ages ages reading various threads on here, it's nearly time for the party wall adjoining the neighbours to have some soundproofing added..

We can hear our neighbours talking, playing tv etc etc and also know they have laminate flooring from when our previous neighbours lived there..

My home cinema setup consists of a KEF T105 system, x2 CA minx for Atmos and a BK sub..the house is semi detached, and its the outer wall of the lounge/dining area where my kit is located..it's approximately 6 meters from where the main LCR speakers and sub sit, to the party wall...I can here there TV which is located in one of the corners and is right up against their/our side of the party wall..

Now the previous neighbours said they could never heard anything, which I find hard to believe ( they were a young family and always yelling at the kids lol) as we can easily hear voices and impact noise on the laminate..I don't have my system anywhere near reference as I'm considerate and always reaching for the remote...we have a thickish carpet throughout the living area, 2+3 seater leather sofas, ceiling to floor curtains, cushions on the sofas, then a 6 seater dining table..Do these also aid in the reduction of sound traveling through to next door?

So here's the plan which seems the favourite on here..stud wall decoupled, rock wool, 12.5mm plaster board, green glue then the 2nd layer of plaster board all edges and joints filled with acoustic sealant..

Questions
1) do I need to do anything to the existing wall or just remove skirting board and fill any possible gaps?
2) I plan on having approximately 100mm air gap from existing wall ..is this enough?

3) I know the top and bottom of the partition will connect to the ceiling and floor, do the sides of the partition touch the existing side walls? ( not party wall) or is this a no no? Sorry for all the novice questions.
 
Bumpy bump[emoji2]
 
1) Yes, seal drywall ie. plasterboard with acoustic caulk at bottom to floor............

2) Attaching wall to ceiling defeats the purpose of dampening..............in US, we attach wall to ceiling using IB-3 decoupling brackets for wall to ceiling decoupling.

IB-3-sound-isolation-clip.jpg
 
Thanks for the response, so you wouldn't suggest attaching any part of the false wall directly?
 
The new wall shouldn't touch the sides/bottom, leave a gap and fill it with acoustic caulk, which can then be sanded and painted accordingly. You're right about decoupling it from the existing wall and filling in any holes/gaps. There are two parts to stopping sound transmission:
- Bass can only be stopped by sheer mass, air gaps and (in a limited amount) vibration prevention; you're addressing these with the air gap, two layers of plasterboard and green glue. Can you use the denser, acoustic plasterboard? It's heavier than the standard stuff.
- Higher frequencies need absorption, which you're also mostly dealing with.

However, your ceiling, other two walls and floor are still coupled to the neighbour's wall, so some bass will still travel through. I wouldn't worry too much to be honest unless you know there's a genuine problem, you can easily run away with yourself and exaggerate...
 
The new wall shouldn't touch the sides/bottom, leave a gap and fill it with acoustic caulk, which can then be sanded and painted accordingly. You're right about decoupling it from the existing wall and filling in any holes/gaps. There are two parts to stopping sound transmission:
- Bass can only be stopped by sheer mass, air gaps and (in a limited amount) vibration prevention; you're addressing these with the air gap, two layers of plasterboard and green glue. Can you use the denser, acoustic plasterboard? It's heavier than the standard stuff.
- Higher frequencies need absorption, which you're also mostly dealing with.

However, your ceiling, other two walls and floor are still coupled to the neighbour's wall, so some bass will still travel through. I wouldn't worry too much to be honest unless you know there's a genuine problem, you can easily run away with yourself and exaggerate...
Thankyou, yes I would use the acoustic/soundbloc plaster board.

The floor plate will be straight into the concrete floor, we have decent underlay under the carpet.

So would you strip back the existing wall or just the skirting board to fill any possible gaps under there? Thanks again.
 
I think if you are only applying soundproofing techniques to one wall, I'm sure you'll be disappointed. For the most part, all in leads to results............anything else is a compromise.
Sound will leak from adjacent walls and ceiling unless properly treated ie. dampen, absorption, mass...........
 
I think if you are only applying soundproofing techniques to one wall, I'm sure you'll be disappointed. For the most part, all in leads to results............anything else is a compromise.
Sound will leak from adjacent walls and ceiling unless properly treated ie. dampen, absorption, mass...........
Thanks, and yes I understand, but also heard good things from people who have only gone down this route, with the one wall.it's basically to cut down on airborne noises from next door and maybe stop some of my home cinema noises going through
 
When we moved house one of the first things I did was build a 100mm timber stud wall 25mm off the party wall at the back of our lounge. Filled it with RS45 universal slab (rock wool equivalent made by knauf) and screwed two layers of 15mm soundbloc board to it. No de-coupling (aside from the 25mm air gap), no green glue, no caulk.

When, as part of our renovations, I took the wall down, I was immediately aware of voices, music from a TV (Eastenders theme tune), acoustic guitar accompanied by a woman singing (that's my neighbour's daughter) and the neighbour's dog barking. Turns out the daughter is in a local band and she plays that guitar at least three times a week for the past few years. Never heard it before!

My coupled, unsealed stud wall might not have been built to any sort of proven standard, except what was in my head. But I'm now very aware of what it was doing. I'm also now confident that I've done the right thing by increasing the wall depth to 150mm, adding more insulation and using resilient bars, acoustic caulk and green glue. The party wall is going to become our screen wall once renovations are complete and I'm trying to lessen the impact on the neighbours as much as possible.

One point I don't fully understand in your original post is the need for a 100mm air gap. I believe the air gap is to give 'the sound' space to bounce off a hard surface and be reabsorbed by the rock wool (or whatever material you're using). It's my understand that it doesn't matter how big this air gap is, just that it exists. As such, why not make it 25mm and put the 75mm saving to better use. Thicker studwork with more insulation, 15mm plasterboard, resilient bars. Or just make the wall construction thinner and make your room 75mm bigger.

Of course, if there's a reason for a bigger air gap I'd be keen to hear it. (no pun intended!)

Edit: typos, grammar...
 
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When we moved house one of the first things I did was build a 100mm timber stud wall 25mm off the party wall at the back of our lounge. Filled it with RS45 universal slab (wock wool equivalent made by knauf) and screwed two layers of 15mm soundbloc board to it. No de-coupling (aside from the 25mm air gap), no green glue, no caulk.

When, as part of our renovations, I took the wall down, I was immediately aware of voices, music from a TV (Eastenders theme tune), acoustic guitar accompanied by a woman singing (that's my neighbour's daughter) and the neighbour's dog barking. Turn out the daughter is in a local band and she plays that guitar at least three times a week for the past few years. Never heard it before!

My coupled, unsealed stud wall might not have been built to any sort of proven standard, except what was in my head. But I'm now very aware that of what it was doing. I'm now confident that I've done the right thing by increasing the wall depth to 150mm, adding more insulation and using resilient bars, acoustic caulk and green glue. The party wall is going to become our screen wall once renovations are complete and I'm trying to lessen the impact on the neighbours as much as possible.

One point I don't fully understand in your original post is the need for a 100mm air gap. I believe the air gap is to give 'the sound' space to bounce off a hard surface and be reabsorbed by the rock wool (or whatever material you're using). It's my understand that it doesn't matter how big this air gap is, just that it exists. As such, why not make it 25mm and put the 75mm saving to better use. Thicker studwork with more insulation, 15mm plasterboard, resilient bars. Or just make the wall construction thinner and make your room 75mm bigger.

Of course, if there's a reason for a bigger air gap I'd be keen to hear it. (no pun intended!)
I think I read on these forums that the gap from the existing wall to the stud wall had to be a minimum of 50mm for it be effective? How much Did it cost you if you dont mind me asking?
 
I can't remember the cost of the original wall. It was four years ago and I was working at a merchant a the time so got staff rates.

The new wall is part of the refurb and I can't honest separate the rates for the wall from everything else. I'm still in the building industry and as such would rather not talk about rates. Sorry.

One thing is for sure, you'll get better rates from a local builders merchants than you will from nationals or DIY sheds.
 
This thread's now a year old - how did you get on?

I have a soundproofing question but it's my bedroom with a party wall shared with the neighbours bathroom; I'd be interested in peoples thoughts on air gaps (yes/no), depth of insulation etc...
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well just doing a bit of this myself...party wall is single course..could hear talking ...baby blaring .sounded like next room not next house

I've done one side....as this wall has a chimney breast I didn't want to go too mad or too expensive as I thought the chimney breast would still be a weak point .

anyway...after loads and loads ....and loads of research and reading...

really wanted to use minimum space so..
ended up building a 50mm stud wall...away from the party wall about 10mm....filled with 50mm acoustic rockwool...stapled a roll of laminate flooring acoustic underlay over it.....mainly as I wanted the rockwool covered until I was ready for boarding and still use the room..as I was impatient getting it started...no idea it was pointless as an acoustic foam...but it was very cheap and covered the insulation till I was ready.

12.5mm acoustic plasterboard on top...acoustic sealant round the edges etc.

the wall is an improvement ...normal talking and baby wingeing is now more muffled...can still hear her when she screaming but it all now feels like they are actually in the next house and not inside mine!

...I used to have to turn my telly up to drown it out but now when i'e it on at normal volume I don't really notice the neighbours.

if I could do the wall again......well not sure if this 10mm gap before the stud was actually worth doing?.....think I'd prefered to use a heavy barrier mat on top of the stud before the layer of plasterboard...which would have probably done a better job of killing vibrations over a small air gap.

...after I did the wall I was watching a video of someone saying an air gap is worse for vibrations :confused: ???

stripped my other wall and I'm now weighing up options on how to deal with that one.....again I really don't want to use much space as theres a gas pipe fixed to the skirting which I might have to get moved slightly.

didn't know if I should do another stud wall and use a barrier mat before the plasterboard...or use resilient bars....on the wall.....some sort of sound barrier foam stuff in between the bars..less than the thickness of the bars....then a mlv barrier...then one or two boards ...total thickness 41 mm

like this dude has done here



trouble is...you obviously don't know the results until afterwards
 
This is exactlz my problem. I have read in some places, air gap is good and make it as big as possible. Then I look at other websites and they mention avoiding a "triple leaf" effect or something?!?

My plan was to introduce a 2.5cms air gap to isolate the new wall from the old one, and then use 10cms insulation before 2 layers of plasterboard.

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Things changed in the end, we had a spare bedroom upstairs ( result!!) It's now our cinema room, we stripped back the old plasterboard on the back wall adjoining onto the other bedroom, we studded it out, added Rockwool, and 12.5mm sounbloc plasterboard, used acoustic sealant on all the joints and I also did the floorboards with acoustic sealant ( my back knew about it lol) I also filled the back of the diy projector screen with leftover insulation for room treatment, used 9mm treadaire underlay, grantite slab sandwiched between 4 layers of cut out treadaire to isolate the sub.

The bass is still heard, but once the sounbloc, Rockwool and acoustic sealant had settled in after around 20 days, going into the bedroom adjoining, the sound is definitely muffled, and sounds distant, if I had the space to double up the plasterboard then I would have, but still has made a noticeable difference imo
 
like this dude has done here


Sorry to dig up an old thread - but it's worth pointing out fot the sake of others that he's fitted the resilient bars upside down! They are designed to be fitted with the fixing screws at the bottom - this is so the weight of the plasterboard pulls it away from the wall. Incorrect fitting can seriously ruin performance.
 
Sorry to dig up an old thread - but it's worth pointing out fot the sake of others that he's fitted the resilient bars upside down! They are designed to be fitted with the fixing screws at the bottom - this is so the weight of the plasterboard pulls it away from the wall. Incorrect fitting can seriously ruin performance.
(notsucha) soundproofingexpert...(!) Well spotted.
 
Sorry to dig up an old thread - but it's worth pointing out fot the sake of others that he's fitted the resilient bars upside down! They are designed to be fitted with the fixing screws at the bottom - this is so the weight of the plasterboard pulls it away from the wall. Incorrect fitting can seriously ruin performance.
Ow... My builders tried even worse - they fitted the bars vertically. No, I'm not kidding. I had them take them all off (luckily they'd only done half a room) and put them back on properly.

What's worse is that I explained it all from the start, and they just said "yeah yeah we know, we've done this before!" :|
 
Ow... My builders tried even worse - they fitted the bars vertically. No, I'm not kidding. I had them take them all off (luckily they'd only done half a room) and put them back on properly.

What's worse is that I explained it all from the start, and they just said "yeah yeah we know, we've done this before!" :|
:facepalm:That's why I do my own building work - only one person to blame then [emoji23]
 
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Sorry to dig up an old thread - but it's worth pointing out fot the sake of others that he's fitted the resilient bars upside down! They are designed to be fitted with the fixing screws at the bottom - this is so the weight of the plasterboard pulls it away from the wall. Incorrect fitting can seriously ruin performance.

Installation instructions vary by manufacturer. British Gypsum show in their Site Book that resilient channel is fixed with the screws at the top, except for the channel at ceiling height.

At my door and windows reveals and the openings I'd made for my inwall speakers, I could see that even with the channel installed "upside down" (screws at the top), two sheets of 15mm soundbloc and green glue hadn't caused the channel to move any noticeable amount. Certainly not enough to make the bar come into contact with the studwork. The 10mm gap I'd left between the boards and the floor was still 10mm.
 
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I'm about to do the independent wall in 2 alcoves. At the moment we barely hear the neighbours, tends to only be loud laughter that gets through, but I want to be considerate so can play louder when my new system is finished.

One thing I am going to try to do different is extend the plasterboard each side.

So cutting into ceiling so plasterboard finishes into the void (rather than joining with 10mm gap sealed with acoustic mastic as usual), and cutting floorboards (suspended floor) so bottom of plasterboard is below the floor rather than sealed with acoustic mastic at a join.

The aim is to keep the sound in my house rather than the neighbours, so any sound that does escape the room through the ceiling or through the floor, I want to make it harder for sound to go along the floor into the neighbours or travelling along the ceiling so by hitting the mass of the plasterboards, it should choose to go and bounce more into ceiling void or floor space.

Same with the side walls, cut away plaster so the 2 sheets of plasterboard are 10mm away from actual brick, rather then Plaster on the brick which may make it easier to flank past

So Brick -> 10mm acoustic mastic -> plasterboard. rather than
Brick -> thin old Plaster -> 10mm acoustic mastic -> Plasterboard.
It should I hope means sound will hit the heavy boards, and then the brick rather than the thinner old plaster reducing flanking.

Also if your existing plaster on the wall is blown, it is important to take that part off and re-plaster so the brickwork is sealed and airtight, something easy to overlook.

Will be doing all the work myself as pretty handy so can ignore any extra cost of making good.
 
So Brick -> 10mm acoustic mastic -> plasterboard. rather than
Brick -> thin old Plaster -> 10mm acoustic mastic -> Plasterboard.
It should I hope means sound will hit the heavy boards, and then the brick rather than the thinner old plaster reducing flanking.

If you can afford to lose the space, I'd recommend fixing 25 x 50mm roofing batten to the sealed wall and then fixing the plasterboard to that. That will give you a small air gap and also minimise the contact points between the layer of plasterboard and the brick wall.
 

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