undercoat floor

Robert hit the nail on the head. I actually had about 3” of water on the floor when I crossed a river last summer, I had to pull my carpet out to get everything dry.
Roccodart, I’ve read about por 15 and actually have a tin of brush on and would love to use it but the surface rust I’m talking about I think I will be able to remove it with a buffing wheel so I’m not sure if por 15 is ideal. I know people say it will peel if used on new metal but what about old metal with no rust ? Or is that defeating the purpose ?