Sound Proofing Wall - Insulation density

[neal1980]

Hi,

I know this comes up alot but after some advice on insulation. I am renovating my house and although my neighbors are a joy i'm future proofing whilst I have the chance with extra sound proofing.

So far I have ripped the ceiling down, first put 10mm sound deadening foam then 100mm 70kg/m3 Insulation then 2 layers of 12.5 Sound Shield Plasterboard.

Now onto the dividing wall I have firstly glued 10mm sound deadening foam, then fixed battens every 600, going to lay 75mm of insulation then 2 layers of Sound Shield 12.5 or 15mm.

I thought from my re-search that the higher kg/m3 the better for sound proofing so I was looking at some Knauf RS140 140mg/m3 but I have found a site that says its a balance and too higher density can be too rigid and make the problem worse. Lots of people using the Rockwool RW45 (45 kg/m3)....but as this is a once off opportunity I dont mind the denser stuff if it will help more.

Can anyone offer and advice, I have the choice of any insulation at the moment 75mm thick.

Neal

[Renovation]

I only know enough to know that it's a specialist field and you have to look at the project as a whole and identify what type of noise you want to reduce.

Very basically heavy dense blocks will stop bass, but if you've been in an empty warehouse they echo terribly and that is solved by soft absorbing material - hence the egg box type foams on the walls in recording studios.

[herbialfa]

If your battens are 75mm deep then I would go for a 50mm deep insulation, leaviing an air gap.

This is more for impact noise which I'd imagine you won't get much as its a party wall but it helps.

[kiethton]

On the rockwall - coming to the end of a refurb and have 2.5 bales of the stuff left after sound proofing all of my new stud walls and laundry cupboard etc.

Welcome to them if you can collect (SE London)