Our garage stands away from the main house and its roof has a very small gradient. The roof consists of thick rubber sheets that have been placed on the underlying plywood, and these rubber sheets were joined together with some kind of flame torch. Is there something I can do as a home owner to prolong the life of the rubber - i.e. minimize cracking and deterioration from sun and weather? (Maybe there is some spray that I can use to keep the rubber soft and effective?) thanks much.....