I took the carpet out to install Wood Laminate Flooring and found dry rot along the outside wall from the front of the slide up along side the drivers seat. This did not happen over night, and I am assuming the slide has been leaking for some time.
I made an appointment to go into an RV Repair shop to have the dry rot sub-flooring replaced and the Laminate installed, so the day before I dumped tanks and went through a Truck Wash, discovered that I leaked going through the truck wash with the slide in tight, so I am back to square one on the slide gasket leaking and not from the top.
If you Coach is more then three years old and you have experienced slide leakage, there may have been some you did not notice and you should check the area for dry rot next to the outside wall. On my La Palma it appears the sub-flooring actually supports the shell of the Motor Home and if like mine it has dry rot, the side could start to sag from a lack of support and cause many other problems.
You can check fro Dry Rot with an awl or ice pick. Poke a few places out in the center area and then over near the walls or where you have found it wet from slide leakage and if it is soft and the awl or ice pick goes in deeper the it did in the center, then have it checked by a professional before big problems develop.