Hi, I removed some old plasterboard from the external vertical wall in my bathroom on the top floor (loft conversion). Behind the plasterboard there was some Styrofoam insulation which had a couple of wasps nests embedded in it and so needed to be removed. The brown paper behind that also had holes and also needs replacing. Behind the paper are the hanging clay tiles on wooden batons. I just want to check what I should replace these with; I assume the paper is breather membrane? I was thinking of stapling a new breather membrane from the inside as can't do it from the outside? Then I was thinking of putting some SIPS Panels between the joists followed by some foil based water resistant plasterboard. Do I need to put in a vapour barrier as well? Any tips and advice would be much appreciated?