i have a fibre glass roof with top coat gray on it. im wanting to go over it but not with a grp top coat paint, as they tend to crack !! what is your suggestion, approx 10 sqm

Assuming the GRP roof is clean, dry, sound and prepared as detailed in the Technical Data Sheet we can recommend Britannia Aquashield Eco.

This is available in black , grey and solar reflective white.

For one coat you will require 20kg.