Roof / Lap sealants

[292BHDSCoachmanMN]

2016 FR Coachmen 292BHDSLE. The lap sealants are starting to crack. Seems like way too soon? only a 1-2 year old trailer but it does stay outside uncovered all the time

Question: do i need to remove the old or just wash it before adding new?

Any difference in brands/self leveling/vs non? I understand vertical surfaces need non.

thanks!

[SeaDog]

the type of lap sealant you use is determined by the type of roof covering you have. Most of what I have seen a good washing and cleaning with denatured alcohol on the areas you are going to apply the sealant. I have used the decor color matched self leveling on the roof. check the mfg recommendations for prep and use