I have a bay window without anything above it, so it has a flat roof proofed
with lead.
I wish to rip down its ceiling (again) and do a better a job of what I did
previously. I will have joists in which insulation can slot, but after that
what do I do. plain plaster board or vapour barrier stuff?
Outside there is a funny hole in the top of the window frame/fascia that
enters this roof space. Iy may have been some form of drainage from the
roof at a time past (now it shovels off the end into a hopper) This lets
the rain in and with the wind in the wrong direction and a heavy downpour
puddles in the room!
There isn't any rot in the roof structure. But this hole may give the
ventilation required to prevent it. Just want to make sure I don't create a
problem by blocking it up. Are these kind of roof spaces vented if so how?

TIA,
Mike W