I have a 1927 flat with a 1970/80s bathroom extension. I am planning on getting a new bathroom as the current one is v old. The room is SE facing and very cold. After every bath the room gets full of mould. I installed new windows but before the bathroom gets fitted I was wondering if there was a way to insulate. My budget for everything, including bath has to be under £10000 as I am borrowing the money. The walls are brick with a flat roof.