Seal as a stop gap roof leak sealer??
That is a good point. Possible problems bonding. I think I remember putting dicor on top of old dicor without any problems with bonding. Never when it has been peeling, just the odd slight crack, which I thought the dicor would just fill in nicely. So far that seems to have worked in a past problem of this type. More recently, I have slathered on the liquid Flex Seal in about the same thickness of the dicor when it smooths out. I did it around four fittings, two circular pipes, the refrigerator vent, and the shower skylight. I'll get some dicor at the next Camping World I come to, get up there, and experiment a little, and report the results.
Puma 26-RLSS travel trailer
27,000 miles towing, 61 weeks camping, 2010-2019
2007 Ram first ten years; 2020 F-150 Lariat >>>>