I would appreciate some advice. We plan to install self-adhesive tile in the kitchen as a 1-year interim to a remodel. We pulled up the vinyl expecting to find plywood. We found old sefl-adhesive tiles installed on something like drywall. We pried up the tiles and the surface is mild fuzzy. Is there a coating or filler I can use on this floor to hold the new tiles? I would prefer not to have to replace the sub-floor at this time.