My 24 years old 32' 5er has had nothing but Dicor added when the OEM sealant needed help or replacing. The trailer was 4 year old when a crack formed in the skylite over the bed. I replaced it with a vent. I used the grey butyl tape like OEM first. Removed the squeeze out butyl then added Dicor over the scr heads and joint. Haven't touched it since.
I helped a neighbor replace Eternabond on his roof (around two skylites) that some newb had poorly applied. I would never add Eternabond over screw heads. Its a bitzh to remove even when poorly applied.
Having worked on RV and mobilehome mostly roof mfg/repair previously I would never add Eternabond over screw heads. Great stuff for hole repair or repairing long tears in roofing material.
