I have similar issues with my Chateau. The wood behind the wing walls delaminated because it wasn't sealed. And everything underneath is very corroded/rusty. My RV was driven in December and got road salt on it, which made things even worse. I've had grounding issues causing errors in the leveling system, and I'm sure it's because of the excessive corrosion underneath.
I have also found gaps in some of the storage compartments and other floor penetrations that I could see light through, so I used expanding foam and flex seal to seal them up.
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