We used it on our RV 36ft fifth wheel roof over 6 yrs ago and it is doing just fine in the HOT Arizona sun. The key is whatever a person coats be sure to clean it well first. We have used it many times on various things---this stuff works great!
My husband covered our RV roof (540 sq ft) with white Flex Seal used about 4 gallons. It has held up great in the HOT Arizona sun for over 6 years and is still fine. You need to divide the roof into 4 sections, mark them off and use 1 gallon per se...