We just purchased an Coachman RV that had taken a tree limb to a small section of the roof. We have been researching the products available to repair it, but need to figure out how to double check whether the roof is rubber or aluminum. Suggestions? My husband says he is thinking it is rubber, but we want to make sure before we purchase something. The area is about 45 x 55" square that we will be repairing and right now we are looking into the Eternabond One step. Suggestions?