Clearance and marker lights are small, but every one of them is a set of screw holes through the roof cap or roof edge. When the sealant around them dries out, water can follow the screws into the wall or ceiling. In Las Vegas sun, that sealant ages fast, so these lights belong on every roof check.
Why roof-line lights leak
RV makers seal exterior parts in layers. KZ RV's maintenance manual explains that exterior components have putty tape between the mounting flange and the surface, with an extra "cap seal" along the edges. Both are exposed to UV, heat, cold and rain, which cause dry-out, shrinkage and cracking. KZ says cap seal must be examined every year, preferably each spring and fall, for looseness, cracking and separation.
Winnebago's operator's manual, as summarized in Benchlet's review of builder manuals, lists clearance lights alongside moldings, windows and compartment doors as items to include in a sealant inspection, and it calls for running a finger along sealant seams to confirm the sealant is still stuck down.
What to look for
- Cracks, gaps or voids in the sealant around the light base
- Sealant that has lifted or pulled away from the cap or roof edge
- Screw heads you can see or feel through thin sealant
- Rust stains or streaks below a light
- A fogged lens or water inside the light housing
- Interior stains, soft spots or bubbling near the front or rear cap
Great American RV's roof guide says that if you can tell where a screw is beneath the sealant, you should cover that area as preventative maintenance, and that small openings can get a dot of sealant while a fully cracked area should be resealed as a whole.
How often to check
Builder schedules differ, so follow your own owner's manual first:
| Source | Interval |
|---|---|
| Great American RV roof guide | At least every 90 days; every 30–60 days if stored uncovered |
| Tiffin Wayfarer manual | Seals around doors, windows, vents, slide-out trim and external seams at least semi-annually |
| KZ RV maintenance manual | Cap seal every year, preferably spring and fall |
A safe light-sealant check
- Use your manual's guidance on roof access. Winnebago's manual (per Benchlet) leaves roof work to qualified service personnel; many lights can be checked from a ladder at the cap.
- Clean the area with a mild detergent and let it dry fully before judging or touching up the sealant, as Great American RV advises.
- Run a finger along the bead. Anything loose, hollow or lifted is a fail.
- Confirm the sealant type before adding any. Great American RV says to check your owner's manual, the manufacturer or the dealer, because only certain sealants work with your roof material.
- Note the light's position and photograph it, inside and out, so the shop can trace any water path.
Do not stack layer after layer. Great American RV notes that when an area has been sealed many times and is piled up, the old sealant should be scraped off and the area cleaned before resealing.
How Sky Sealed handles roof-line lights
Sky Sealed is shop-only at 4416 Alderbaren Ave in Las Vegas. We do not send a mobile crew to driveways, storage lots or campgrounds. In the shop we assess membrane health, seams, decking and penetrations, including the cap and roof-edge fixtures, and then recommend the right system with a written quote. Our systems use embedded fabric at seams, vents and penetrations. On qualifying full systems we provide a 20-year workmanship warranty, with terms in writing before pickup.
Light wiring, lens replacement and electrical repairs are separate from roof sealing. Ask your dealer or RV technician about those.
Frequently asked questions
Why do RV clearance lights leak?
Each light is fastened with screws through the cap or roof edge. Putty tape and cap seal around it dry out and crack with UV and heat, letting water follow the screws inside.
How often should I check the sealant around marker lights?
Follow your owner's manual. Great American RV suggests at least every 90 days, or every 30–60 days if the RV is stored uncovered. Tiffin and KZ call for semi-annual or spring-and-fall checks.
Can I just add more sealant over the old bead?
Only with the sealant type your manufacturer approves, and only over clean, dry, well-bonded sealant. If the area is piled up from repeated touch-ups, the old sealant should come off first.
Does Sky Sealed come to my storage lot?
No. Sky Sealed works only in our shop at 4416 Alderbaren Ave in Las Vegas. There is no mobile crew.
Book a shop inspection
Seeing rust streaks under a marker light, or a stain near the front cap? Bring your RV to Sky Sealed at 4416 Alderbaren Ave, Las Vegas, NV 89103, along with photos of the lights and any interior marks. Call (702) 296-7300, email curtis@cbtbllc.com, or use the quote form.
Book a shop inspection and get a written quote to seal every roof-line penetration as part of a full roof system that lasts.