05/09/2026
The most overlooked RV roof sealant area are the trim rails. These are where the edge of the roof fiberglass or membrane transition to the sidewalls. Once they crack or develop gaps, it is an opportunity for lots of water to intrude into the coach.
Inspectors evaluate every inch of roof trim rail sealant, and yes, we find defects on both new and used RV's. It is an easy fix using an RV appropriate non-sag lap sealant. As a pro tip, never use silicone sealant. It is simply the wrong product for the job. If you DIY apply lap sealant on the trim rails, I recommend masking tape above and below the seam. This can be a messy job and difficult to clean mistakes.