Sound Reduction for a Solid brick bathroom party wall

[NorthWest1]

Hi,
I've been reading through older posts and it seems quite a contenious issue. I'm doing a bathroom install in a solid brick semi detatched . The room has party wall which is simply plastered ( originally a bedroom ) and stud walling to bedrooms. My only goal is to provide some sound insulation to the neighbouring party wall and I recognise that its certainly not going to SOUND proof it ( that's complicated and expensive ). My proposal is to;

1. 50mm Stud to original plastered brickwall ( fitted on original plaster ).
2. 50mm Acoustic rockwool
3. resillient bar to studding
4. Moisture resistent plasterboard
5. Final surface finish i'e, insulation board XPS & tile or panelling

My concerns are,
1. Will it make any difference at all or would I be better just sticking the final surface finish to the original plaster ?
2. Could adding studding and insulation cause moisture issues at the end of the wall, where the outside wall meets, or within the studding/insulation ?

Sorry, I know ppl must be sick of this topic but there doesn't seem to be a definitive method despite there being millions of houses built the same way, that could do with basic retrofit sound reduction.

 

[Deleted member 323070]

My concerns are,
1. Will it make any difference at all or would I be better just sticking the final surface finish to the original plaster ?

I'm no expert, but it sounds like your suggestion will make a substantial difference to sound transmission.

2. Could adding studding and insulation cause moisture issues at the end of the wall, where the outside wall meets, or within the studding/insulation ?

Moisture resistant board has essentially an in-built moisture barrier. So no moisture can be transmitted to the brick walls.

There is a subtle difference between moisture resistant board and vapour resistant board.
Vapour resistant board has more or less the same properties as moisture resistant board but has an additional vapour resistant layer, which often appears as a metal foil layer to the back of the board, in addition to its moisture resistance properties.

 

[Ivor Windybottom]

Are you tiling over it? If so ensure there's no "give" in whatever you use. A lot of soundproofing relies on rubber mountings or flexible mounts, e.g. resilient bars. I'd be inclined to make it rigid (so less soundproof), but knowing that it will be strong and won't crack or lose any edge seals.

Resilient bars are intended for dangling a ceiling from, e.g. for a flat conversion. Nobody's ever going to push the ceiling up with more force than a sheet of plasterboard's weight is pushing down. But it you're leaning on a bathroom wall while towel-drying or whatever that's totally different.

You will gain lots of sound attenuation just by adding the studs and rockwool.

 

[NorthWest1]

Thanks for replys,
Yes, was gonna tile up to half way height around room, then either plastic panelling or just water proof bathroom paint. Never gave any thought to the wall being flexible, that would obviously be a big no no.

 

[phatboy]

50mm metal stud at 400mm centres, with 50mm Rockwool RWA45 between would be good (They design them for 600mm centres, so cut cut them into 3x 400 sections from a 1200mm long panel).

Use blue soundshield plasterboard, 2x 12.5mm layers if you can, or a single 15mm layer.

Keep the studs 10mm off the original wall, and fix only into the floor and ceiling, nothing into the brick wall. Use Rockwool fire / sound sealant around the perimeter, and where any boards aren't completely tight together.

I don't know which elements of that make the most improvement, but it's what I've done isolating the sound between 2 rooms separated by a 4" block wall.

 

[endecotp]

Keep the studs 10mm off the original wall, and fix only into the floor and ceiling, nothing into the brick wall.

This is the important bit. I doubt resilient bars will be useful; if you do use them, use panels rather than tiles as there will be some flex.