How to soundproof walls?

AdmanPea

Hi 

I live in an old 1935 semi detached house with solid party walls that I assume aren’t overly thick. I can hear tv noise through the wall next door and talking when it’s loud. Is there a cost effective way to soundproof the party walls to minimise this? I contacted a company who talked about taking 6 inches off the room size by essentially building an extra wall between the two. I’m aware this is probably best but without losing that kind of room and something more cost effective, are there other options out there? 

Thanks 

Rosa_Damascena

Presumably your neighbours can hear sounds from your side of the wall too?

The cheapest and easiest solution may be to renegotiate where the TV set is sited?

Apjs87

6 inches?! Surely a good result can still be achieved by battoning off the wall, adding polystyrene between the batons and then finishing the wall in sound proof plasterboard?

Alter_ego

Apjs87 said:

6 inches?! Surely a good result can still be achieved by battoning off the wall, adding polystyrene between the batons and then finishing the wall in sound proof plasterboard?

Polystyrene is an excellent sound TRANSMITTER. Try putting some by your ear and gently scratch the other end

GDB2222

The new wall needs to be acoustically isolated from the party wall, so what the expert company said is about right. You might get away with only losing 4 to 5 inches, rather than 6, but you need a framework that is separated from the party wall by an air gap of say an inch. That's say 3 x 3 timber, with two layers of plasterboard applied on top. Including the air gap, you can see where the 6 inches comes from. These days, the framework is usually steel, which is a bit thinner. 

Still, to do it properly, you are talking about thousands. And, don't forget that the floor joists are set into the party wall, so the floor may be transmitting a lot of the sound.

And, you can get this stuff:
https://www.wickes.co.uk/Knauf-Sound-Panel-Tapered-Edge---12-5mm-x-1-2m-x-2-4m/p/224657

That may save you a cm or two, as maybe you can get away with one layer of that instead of two layers of ordinary plasterboard.

FaceHead

2 inch batons, 25mm rockwool in between covered with 12.5 or 15mm acoustic plasterboard and skimmed over. Total thickness max 3 inches. 

A less labour less effective way would be to just dot-dab an acoustic plasterboard on and skim over. 

Assuming you've currently got undercoat plaster skimmed over, you could remove that (very messy) to recover some space, but it's probably not worth it. 

Yes the wall is only part of how the sound gets to you, but going from wet plaster to something actually designed to insulate sound will be a big step in the right direction.

eddieacton

Hi,

I have to soundproof a stud wall between two en-suites. My plan was Rockwool in between studs, then mass loaded vinyl stapled to the stud, then resilient channel, then tile back board screwed into the channel. But I'm a bit unsure about whether the resilient channel would make the board too 'flexible' to be tiled. I could do sheets of acoustic plasterboard onto the channel and then the backer board on top of that? Has anyone had success with tiling direct onto resilient channel?

Gavin83

Do you know what the current wall construction is? How loud is it?

I’d probably go with something along the lines of what FaceHead first recommended, although I’m not so confident on the dot and dab recommendation as I don’t think that’ll do anywhere near as good a job, although it’ll save you space. If you want an even better solution make the wall thicker, with thicker rockwool, or even consider leaving an air gap as well. 

I’m not an expert on sound insulation but my understanding is the rockwool will help to stop ‘normal’ sounds and the air gap will help prevent vibrations, such as from a subwoofer.

The problem with this is you can’t really tell how effective it is until it’s done but you don’t really have a choice.

Also as pointed out sound could be transmitting via other means, such as through the joists. That however is a lot harder to resolve unfortunately.

If you’re handy enough to do the work yourself though and the room is of an average size I’d expect the above suggestions to cost somewhere in the region of a few hundred quid.

plumb1_2

Alter_ego said:

Apjs87 said:

6 inches?! Surely a good result can still be achieved by battoning off the wall, adding polystyrene between the batons and then finishing the wall in sound proof plasterboard?

Polystyrene is an excellent sound TRANSMITTER. Try putting some by your ear and gently scratch the other end

And a fire hazard 

eddieacton

Gavin83 said:

Do you know what the current wall construction is? How loud is it?

I’d probably go with something along the lines of what FaceHead first recommended, although I’m not so confident on the dot and dab recommendation as I don’t think that’ll do anywhere near as good a job, although it’ll save you space. If you want an even better solution make the wall thicker, with thicker rockwool, or even consider leaving an air gap as well. 

I’m not an expert on sound insulation but my understanding is the rockwool will help to stop ‘normal’ sounds and the air gap will help prevent vibrations, such as from a subwoofer.

The problem with this is you can’t really tell how effective it is until it’s done but you don’t really have a choice.

Also as pointed out sound could be transmitting via other means, such as through the joists. That however is a lot harder to resolve unfortunately.

If you’re handy enough to do the work yourself though and the room is of an average size I’d expect the above suggestions to cost somewhere in the region of a few hundred quid.

Thanks for replying. It's a new stud going up so we have flexibility to design it. So far I have rockwooled in the cavity, stapled a heavy mass-loaded vinyl to it and am then putting resilient channel on, with acoustic plasterboard on the other side. The acoustics boffins I spoke to said this was a good system, but my worry is that on the shower side, which needs tile backer board, screwing the light, small sheets of tile backer board onto the flexible resilient channel will result in cracking tiles if someone leans on the wall etc. 

NSG666

For info, eddie has started their own thread on this

Bathroom Soundproofing — MoneySavingExpert Forum