If this is a rubber roof, Use the Dicar membrane repair tape. With rubber roofs ya got to be careful with what you use on it as any petroleum products will cause un-repairable damage to the membrane. I would ask but I don't think that coating the membrane is a good idea. i would repair the roof and clean it and put on a rubber sun blocker.
1991 Chevy Pickup
1994 5th wheel 30 foot trailer