Hi, I have a shared concrete roof with my neighbour. I can access it via a side door of my property and it has a covered passageway and 2 small rooms. It's currently totally uninsulated but I'm planning on running water to the furthest room to plumb in the washing machine and want to add a little insulation to prevent pipes freezing.
The problem I have is that there is only 55mm from the top of the windows/doors and the roof. I can't insulate on top due to it being a shared roof and there is no room for a ventilation gap for a cold roof. Do I just stick celotex to it and accept I'll have moisture issues or is there another solution?
Thanks for the help.
Ben