Hi
The back bedroom of my Victorian house has 2 cold exterior walls. They were plastered 20 years ago and the plaster is good. I want to insulate them by fixing polystyrene backed plasterboard to the walls, (40mm boards) then replaster.
I've read about glueing boards to the wall with plasterboard adhesive but can I use this method on the polystyrene backing? Is the plasterboard and polystyrene fixed firmly together or is there a danger that the plasterboard could come away? Would I need to use some sort of fixing screws as well?
Thanks! :D