There are a couple of options for sealing your fiberglass roof.
Prepping the metal roof on my rv.
How to seal your rv roof.
If you need to repair structural damage not just seal a roof eternabond seam tape is the product for you.
This will make for easier installation but will follow the same basic steps.
They re found mostly on vehicles from the 80s and 90s though there are a few modern rvs that sport them as well.
Before epdm and tpo metal was the material of choice for rv roofs.
A tutorial on technique and products used to protect your roof.
Household roof coatings will seal a metal roof just fine but the best product by far for metal roofs is kool seal.
Having said that fiberglass rv roofs require less maintenance than rubber rv roofs which makes them preferable for some campers.
Installing a metal roof on a rv is no different than installing a metal roof on any other type of roof with the exception that the rv is not sloped.
Fiberglass this type of rv roof is hard to the touch and is a bit more rare than a rubber rv roof because the material adds cost and weight to the rv.
Fiberglass rv roofs are rarer than metal or rubber roofs.
With that said though there s nothing wrong with having a good sturdy metal roof but to keep it good and sturdy it helps to know a thing or two about metal roof repair.