markandkim, it's a rubber roof on a 24' outback trailer, 2005 rubber roof which the PO never maintained.
Scott repaired the left side edge of the roof where it comes over the side with new material about 4" and the length of the trailer and you can't even see it. Apparently he uses an acrylic that he formulated and lab tested. As I said he's very knowledgable has work on Rvs and Trailers for a long time and by talking to him sounds like he's been in just about every state. Contact him he'll answer all your questions and send a sample. I'm not affiliated with him in any way just very satisfied in his work and a cheaper solution to a new roof.