My plan is to slather a few layers of stuff up there. Bed liner makes a good durable skin that won't get scraped off, then a thermal barrier paint like bus kote.
Honestly the reason for the bed liner is that its catalyzed and cures in about two hours. After that it can rain and it doesn't matter. If I was in a dry climate right now I'd go for the buskote or solarflex.
For instance, I am currently sort of "trapped" in the bus with an unusual pacific northwest fall monsoon outside.
Originally Posted by Tango
You might check HyTech Bus Kote. Made specifically for bus roofs plus is a truly remarkable thermal insulator. Having seen it in action on a tin roof in 110 degree Texas heat, I'm using their insulating beads on all my body panels and will be applying the Bus Kote to my roof.