How should an AC unit be SEALED on the RV roof?
Apply the self-leveling RV roof sealant in a continuous ring around the roof opening before mounting the unit. If your model doesn’t include a pre-installed outlet gasket, attach it to the roof first, press it down firmly, and then seal around it to prevent leaks.
Preparing the Roof
Start by ensuring the roof surface is completely dry, clean, and free of oil or debris.A clean surface helps the gasket and sealant adhere properly and prevents leaks later.
Attaching the Outlet Gasket
If the air conditioner’s outlet gasket isn’t already attached:
Peel the backing paper.
Center it over the 14 ¾ × 14 ¾ inch (360 × 360 mm) opening.
Press evenly to ensure full contact and adhesion.
Applying the Sealant
Use a self-leveling RV roof sealant and apply it in a closed, unbroken circle around the outer edge of the gasket.Make sure the sealant fills all gaps to prevent water intrusion,but avoid contact with the rooftop unit itself.
If Your Unit Has a Pre-Installed Gasket
Skip the attachment step and apply self-leveling sealant directly in a continuous circle around the square opening before installation.
Corky Lorenz
November 4, 2025