I have a plasterboarded ceiling which I need to insulate to make the lounge above warmer. The plasterboard is 2 x 12.5mm and skim and I don't want to remove it. I also can't use anything with foil (disrupts a zigbee signal to Octopus) and am looking at fixing rockwool batts direct to the ceiling. Not sure if I need a vapour barrier between plasterboard and rockwool - appreciate advice on this please.
