The foam rubber seal should NOT be the actual watertight seal for the slide room. I assume you are talking about the 1 inch square foam rubber "gasket" that is installed to keep the slide out interior flange/fascia from marring the inside walls? If so, there is a criteria for installing this type gasket/seal. 1. make sure the area is CLEAN. 2. The best application is done with a adhesive "enhancer". This is a type liquid that is spread on the area to be adhered to and promotes bonding. Usually when this is used and done right, it is a bear to then remove the new Gasket/seal. Doug