If your caravan roof only has minor leaks and you have been able to identify where they are it might be worth rethinking whether you need to replace the whole roof or resealing the roof would be an option.
Static caravan roof vent leaking.
Some leaks can be hard to track to their source but one i recently found was a pretty straightforward job.
Most caravan leaks occur at a join or attachment hole where a screw or rivet holds down the sheeting to the frame.
Sun exposure and heat especially during the summer can cause the rubber boot to crack creating the space for water to leak in.
Replacing the entire roof is never a small job.
It was leaking through the join of the handles so i fix it using a foolproof method buy the mastic that i used h.
Unfortunately the rubber boot damage often becomes the main cause of roof vent leaking.
Many years ago i had an untraceable leak in a static caravan eventually i applied water to the roof containing drain tracing dye.
Doing a quick repair on my caravan skylight.
I applied different colours of dye to small areas at a time eventually i narrowed down the leak source colour of dye emanating within the caravan.