Insulating false wall

[Jamie2106]

I've found lots of information on what to do when insulating a solid wall but nothing for this situation, hoping someone can help please.

I'm building a false wall on the bathroom to hide the pipes, essentially boxing them in but floor to ceiling. The external wall is a cavity wall, plaster intact, and I'm attaching 25mm x 50mm roofing battens directly to it.

I feel I should put some insulation in the gap between the battens and plasterboard, even though the wall isn't really cold. So I need to know whether to do:

Jablite on the basis something is better than nothing

Celotex/Kingspan - higher cost but even better than nothing

One of the above plus a vapour barrier

Thanks in advance

 

[Ian H]

For an internal wall i’d be looking at the best acoustic stuff you could get in there.

 

[Jamie2106]

Thanks, I've put acoustic insulation in the wall adjoining the bedroom but it's the exterior wall I wasn't sure about

 

[23vc]

Not needed, already on the “warm” side of the cavity wall

 

[Jamie2106]

Is that no vapour barrier needed or no insulation needed at all?