Looking for something to keep water from getting between the rail and the bottom edge of the roof. My roof is vinyl covered and rail fit is tight but probably won't prevent every bit of water from getting between roof and rail. My thinking is, with the rail removed, a smear of something on the bottom of the vinyl edge will create a water proof barrier. Want to be able to remove the rail in the future so avoid a strong bond that will damage the vinyl. If this is not possible will do without. Looking for a filler to close the gap between the rail surface that mates with the underside of the roof. A water seal is not needed for water can not migrate up to this area. Do not want a strong bond for I want to remove the rail in the future.