Slide Out Floor Replacement – Rot Repair (long w/pics)

It looks like they coated the edge of the OSB with Flex Seal, Plasti-Dip or some kind of rubberized coating. Mine is made the same way where the floor attaches to the bottom of the side walls. It's supposed to be covered by the lower trim piece, but the trim didn't quite cover it all....Once water found its way in, OSB swelled like a sponge, creating bigger gaps in the coating so it got progressively worse.