I have been probing the roof as it felt cold and wet around the skylight, so I removed the surround and measured the wood frame of the roof panel itself and it reads 5% but the thin foam and cloth, of the headlining has bits off the clock 24% plus and yet in other places 5% I have a load of sealant and tape so I will reseal the whole thing but was wondering if it could just be condensation as the damp is a fair way from any openings. I have also got a bit of staining where dampness has marked the cloth, what would be the best way of moving that without water? I am selling the van and want to make sure there is no problems with leaks for the next owners and I am paranoid about water getting in causing rot in the wood frame . WHY is wood still used?.