If your roof suffers from bigger tears then fiberglass repair tape is a recommended solution.
How to repair truck pop up fibverglass roof.
The sealing process of a leaky fiberglass roof is not too different from its rubber counterpart.
In case there are substantial damages fill the holes with roof patching tar and cover them with fiberglass tape.
Put on a respirator and safety glasses.
You will need to work very quickly as the mixture dries fast.
Put the mixture on the cracks.
How to fix cracks in hard shell pop up campers.
Gradually taper the walls of the grove to give the repair a maximum amount of surface area to bond to.
Clean the area of the crack with the 36 grit sandpaper making certain to thoroughly gouge the area of the crack with the paper.
Grind directly on the damage with a dye grinder until all the frayed and damaged material is ground smooth forming a grove in the fiberglass.
After spreading the leak stopper or tar add fiberglass screen tape on the hole covering it whole.
Spread the sealer all over the area that needs a patch lay a piece of fiber glass tape over the patch cover it with more sealer.
Apply additional layers of tar and sealant on top of the tape to finish the process.