Bathroom wall insulation (1939 house)

[CO2000]

Hi,
I have a bathroom under renovation & wondering about insulation. Its a 1939 house with lath & Plaster walls. I'm possibly taking the lath & plaster off & replacing with moisure resistant Plaster Board.

If I do would it be a good idea to use kingspan or similar on the outside wall (1) or/and the internal walls (3)

Thanks for any help,

Cheers.

 

[advancemaintenance1]

i wouldnt bother on the external walls ( cavity insulation would be better ) but on the internal studs i normally use rockwool not just for heat insulation but sound too. who wants to hear someone peeing in the next room , or worse

 

[CO2000]

Sorry should have added its a solid Granite house. When I got a wall plaster boarded in the Kitchen the Guys used Kingspan & it was an exterior wall. The problem I see is that the rest of the house is not really insulated just the odd bit in the eves.

Its a one & a half story house and the eves are partially floored with no insulation under them as from the un floored part of the eves you can see right under the floor to the other side (there is a 6-8" gap between ceiling & floor) There is no way of getting to the inside of the roof as there is no loft space just eves.

Maybe I should see what the Council IOnsulation Grant contractor says about this style/age of house.