Currently redoing the bathroom. Have ripped it all out and expecting some damp problems, we got prepared for that.
Now, our house is on a hill so you enter at street level after crossing the drive (it could be a drawbridge with some extensive modifications) and have to go downstairs to the bedrooms and bathroom and to get into the back garden. As a result, there is a void space under the house of about 4ft.
Previously, we replaced all the heating by re-routing it more efficiently, put a new kitchen in and basically made things much better. The void space was handy for the bedroom heating as all the pipes are now hidden under the floor.
So our plan was to use the void space to route all the bathroom plumbing and as such, a few years ago we set it up so we could. Have now ripped up some of the floor and found that the rockwool insulation is soaked. Half the floorboards were rotten too so after many hours of battling against walls that aren't straight, we have water resistant Chipboard flooring down.
It would have been quicker but the hire van we had to pick everything up in had its tyres slashed last night outside the house so that cost us a few hours.
All in all, a good day