Having taken all the walls and ceiling off in the bathroom, what was revealed was pretty dirty and rusty and flaky, and looked a lot like a serial killers lair
Before i sealed it all away for the next 20 years i wanted to get the metal rubbed down and repainted, so that it was in good condition and we could not worry about it. I grabbed a wire bristle brush on a drill
and spent a couple of days getting EXCEEDINGLY dirty and grimy rubbing off all the loose paint and rust
before painting on a nice coat of undercoat
After doing one wall i ran out of red oxide, but found a big tin of grey in the engine room so frinished with that. As it's all getting covered up by insulation it doesn't make any difference.
Having (mostly) contained the mess of painting with tarps
it was time to break out my second favourite stuff after celotex, expanding foam,
and get insulating.
I cut pieces of celotex to fit between the ribs, keeping the edges on an angle, so that i could then fill between the angled edge and the rib that it butted up to with expanding foam, creating a tightly fitted, airtight seal that wouldn't, unlike the plastic sheet and rockwool that was there before, allow any moisture, or heat, to pass between the room and the hull and create condensation.
Doing this does leave the edges of the ribs protruding through the insulation, but when we've attached brackets and battens we can then add another layer of insulation, which will cover these up too.