Teardrops n Tiny Travel Trailers

Has anyone used Tile Mastic to adhere FRP?

It sounds like a good idea because you can slide the FRP around to position it, It is white, and it is waterproof.

What do you think?

I used it years ago to attach Filon to the sides of a tear . When it dried it got hard and eventually cracked under the Filon. Separating the bond between the wood & Filon.
I like using silicone applied in about 1" round Gobs or balls. Every 6-8 inches. Its sticks very well, it dries flexible and putting it on in gobs takes care of expandtion problems.
There are other adhesives, I just prefer, and have access to a lot of silicone.

Happy Trails

Len