Outside Square Skylights

What size opening do outside square skylights fit?

Most RV outside square skylights in this collection fit a standard 14" x 14" roof opening, which is the common cutout for RV roof vents and skylights. Always measure your existing roof opening before ordering, and confirm the outer flange dimensions clear any adjacent roof components. If you are replacing a damaged unit, match the dome height as well so your interior trim ring still seats correctly. For premium dome options, see our Icon Premium Skylights collection.

How do I install a replacement RV skylight dome?

Remove the interior trim ring, then unscrew the old skylight from the roof and lift it free. Scrape away the old sealant down to clean roof material, set the new skylight in a bed of self-leveling lap sealant compatible with your roof type (TPO, EPDM, or fiberglass), reinstall the mounting screws, and run a second bead of sealant over the flange and screw heads. Reinstall the interior trim ring last. Plan the job for a dry day and check the seal again after the first rain.

What sealant should I use around an RV skylight?

Use a self-leveling lap sealant rated for your roof membrane, Dicor 501LSW for TPO and EPDM rubber roofs is the standard, or a butyl tape under the flange plus a non-sag sealant on vertical edges. Avoid generic silicone, it will not bond reliably to RV roof membranes and makes future resealing harder. Inspect the bead annually and reseal at the first sign of cracking. If you are sealing other roof penetrations at the same time, browse related parts in our Ventline Vent essential accessories collection.

Why replace a cracked or yellowed RV skylight?

A cracked or hazed skylight is the most common entry point for water leaks above an RV bathroom or shower, and UV damage weakens the dome until it shatters in hail or high wind. Replacing it restores the watertight seal, brings back interior daylight, and protects the ceiling, wall panels, and subfloor from rot. If you are tackling a full roof refresh, also check your roof vents and seals against our RV winterizing kits for off-season storage protection.