Sealant Cracking On Roof Vents and Ducts On Camper

Updated 07/25/2026 | Published 07/20/2026

Question:

I have a 5 year old cab over camper with a rubber roof. No leaks currently in the roof itself, I keep it clean and treated. However the thick sealant around all the roof vents and ducts have fine hairline cracks on the flat surface of the sealer. What can I purchase to seal these fine cracks before they get worse and eventually create a leak? Thank you. Ron

asked by: Ronald S

Expert Reply:

Hey Ron! Fine hairline cracks in the surface of the existing lap sealant are pretty common and don't necessarily mean the seal has failed. If it's still firmly bonded, I recommend cleaning the area and applying a fresh layer of self-leveling lap sealant like Dicor # DC94SR over the existing sealant to renew the weatherproof seal.

If the existing sealant is lifting, separating from the roof, or has deep cracks all the way through, then it's best to remove it and reapply new sealant instead.

What kind of camper are you working on?

expert reply by: Robin H