My 96 Itasca is doing the same thing, the glue that is on the vinyl for the foam pad is what failed. I purchased a 36ft roll of Boat hull liner, this is what is used on a lot of newer RV's. When you do this make sure the glue you get is High temp. Then remove all the upper cabinets and furniture and get ready for the dirty job of scraping the old foam off so you have clean surface for the new glue to adhere to.
96 Itasca Sunrise 33RQ on F53 Chassis