Overboarding

[Michaelsf90]

If I am to batten out a party wall to add acoustic insulation and soundproof board should I batten the wall, add the rockwool in the gaps, use foil backed 12.5mm board first then use 15mm soundbloc board? I keep reading conflicting things on wether I need some form of vapour barrier. Any help would be much appreciated

 

[John D v2.0]

Better to isolate from the existing wall w much as possible. Make sure you seal around the edges to avoid flanking noise. Vapour barrier would be a nice idea as the backing wall will get colder so more chance of condensation

 

[Michaelsf90]

I've done my research on all the soundproofing techniques. Batten away from the wall. Resilient bar. Acoustic sealant. I'd have used celotex but it has no acoustic properties and the whole point of doing it in the first place is to soundproof. I just don't want to cause any damp and it's hard finding proper information on using a vapour barrier. Some say not to use one at all as it could cause more problems. I think the same even tho it's a party wall that cavity I'm creating will be colder. But is the foil backed plasterboard any good acoustically

 

[John D v2.0]

Foil backed would be the same as normal, but as you're mechanically fixing rather than tdot and Dab just get a poly sheet and staple it to the battens. Then you can detail the edges better.
I don't see what problem a vapour barrier would cause, as long as it's on the warm side of any insulation. Party wall is normally treated as no heat loss because it's heated both sides but there will always be some thermal bridging at the edges meaning it will be colder if internally insulated.

 

[^woody^]

wether I need some form of vapour barrier.

No you don't. It's a party wall.

 

[Notch7]

No you don't. It's a party wall.

Maybe next door sweat a lot