RV sealant FAQ

Self-leveling sealant flows out to seal flat, horizontal joints like vent flanges and screw heads. Non-sag (non-leveling) sealant holds its shape on vertical surfaces like front and rear roof edges and termination rails. Dicor makes both (501LS self-leveling, 551LS non-sag).

Dicor lists its self-leveling and non-leveling lap sealants as compatible with EPDM, TPO and PVC membranes.

No. Geocel says not to use Pro Flex RV on EPDM or TPO. It's made for aluminum, fiberglass, wood and vinyl joints such as sidewall seams, trim and tail lights.

Usually not. EternaBond says its tape isn't recommended on silicone-treated surfaces, and RV Roof Magic says its coating can't go over silicone. Remove old silicone down to a clean surface first, and check your product's label.

Check the label. EternaBond says to apply between 40°F and 150°F and to use its EternaPrime primer below 40°F. Dicor says to warm lap sealant tubes to room temperature in cold weather.

Dicor's guide for its lap sealants at 50–70°F: skins over in about 5 minutes, waterproof in about 4 hours, 80% cured at 48 hours, and fully cured at 30 days.

Dicor makes a gunnable butyl sealant it lists for windows, vents, skylights and termination rails, for the primary seal between lapping parts. For exterior joints on fiberglass or aluminum sidewalls, Geocel Pro Flex RV is made for that job.

If only joints are cracked, reseal them. If the membrane itself is worn across the roof, a roll-on coating is a different job. When unsure, have an RV service center inspect the roof.

No. We don't run lab tests and we don't publish star ratings. Our picks are matched to what each manufacturer's own spec sheet says the product bonds to and where it says not to use it. We link those sources so you can check.