WINNEBAGO EKKO – Roof Seal and Skylight Maintenance

Roof Seal and Skylight Maintenance for WINNEBAGO EKKO

I was standing on the Transit 350 HD roof of a 2022 Ekko last month, eight-foot ladder planted on asphalt, running my fingers along the rear cap-to-metal roof seam where the fiberglass composite curves down to meet the factory Ford roof structure. The sealant there was separated, chalky, and lifting at both edges—the owner had no idea it was failing because the damage was invisible from the ground and they’d never actually looked at it closely. That one seam, left unchecked, had already allowed enough moisture beneath the surface to delaminate a three-foot section of the fiberglass cap and soften the headliner near the Fantastic Fan opening. By the time someone finally climbs up there and finds it, water damage that started with a hairline crack has become a five-figure repair involving fiberglass work, wall cavity remediation, and cabinet replacement. This guide walks you through what I do on-site to catch these failures early and execute the fixes that actually stick: which products bond properly to both fiberglass and EPDM, where the Ekko’s most dangerous leak pathways hide, and how to reseal without creating new failure points downstream.

Required Parts

• Self-leveling Dicor lap sealant (white, 10.3 oz tube) Dicor 501LSW-1 EPDM Self-Leveling Lap Sealant, 10.3 oz – White
• EternaBond RoofSeal tape (4″ × 50 ft roll) EternaBond RoofSeal White 4″ x50′ MicroSealant UV-Stable Roof Repair Tape
• EPDM rubber roof coating – 1 gallon HENG’S Industries Rubber Roof Coating, 1 Gallon, EPDM Waterproof UV-Resistant
• Dicor rubber roof cleaner and degreaser – 1 gallon Dicor RP-RC-1GL Deep Cleaning Rubber RV Roof Cleanser Spray Refill, 1 Gallon
• Plastic putty knife set (for removing old sealant without tearing membrane) Rerdeim 5-Piece Putty Knife Scraper Set, 1″–5″
• Professional drip-free caulking gun Newborn 930-GTD Drip-Free Smooth Hex Rod Cradle Caulking Gun, 10:1 Thrust Ratio
• Liquid Rubber EPDM/TPO primer – 1 gallon Liquid Rubber EPDM and TPO Primer, 1 Gallon – RV Roof Basecoat
• 3-inch paint roller kit (for applying roof coating) ROLLINGDOG Small Paint Roller Kit, 3 Inch with Tray and Stir Bar
• J-roller (for pressing EternaBond tape to full adhesion) POWERTEC 12″ Long Handle J Roller, 1-1/2″ Diameter, 3″ Wide

Step-by-Step Instructions

Step 1: Set Up Safely and Do a Full Roof Inspection

The Ekko climbs to roughly 9.5 feet at the roof peak when sitting unladen on the Transit 350 HD frame—a standard six-foot household ladder leaves you overreaching and unstable. Grab an eight-foot step or extension ladder and pair it with a roof walk board or foam kneeling pad that spreads your weight across the membrane instead of concentrating it on one spot. The fiberglass rear cap extension will crack under point-load pressure; you step on it wrong and you’ve created the exact leak point you’re trying to prevent. Begin your systematic walkthrough at the front Transit section and move backward methodically. Zero in on five categories: any Dicor that’s cracked, separated, or chalky-looking around penetrations like the Fantastic Fan ring, antenna mounts, and solar conduit entries; EternaBond tape that’s peeling, bubbled, or showing daylight along its edges; soft or squishy zones in the fiberglass cap indicating subsurface water damage and delamination; gaps opening at the transition where the fiberglass rear cap bonds to the metal Transit roof; and rust bloom or discoloration on the metal panels suggesting pooled water sitting in one spot. Use a flashlight held at a shallow angle to make hairline cracks jump out visually. Take photos of each problem area in strong light before you begin repair work—these before shots matter more than you’d expect when tracking how long a seal actually lasts. The four corners of the Fantastic Fan curb deserve extra scrutiny; they flex when the van frame twists under load and crack their sealant perimeter within the first couple of seasons on most units.

Step 2: Clean the Entire Roof Surface

Your new sealant bonds only as well as the surface beneath it—if that surface is grime, oxidation, or decades of weathered sealant residue, your fresh Dicor will sit on top like frosting on a greasy plate and eventually fail. Mix the Dicor rubber roof cleaner and degreaser at full strength (don’t water it down for this job; dilution is for light maintenance washes, not pre-repair cleaning). Work in sections using a soft-bristled brush, moving front to back so dirty rinse water doesn’t run across areas you’ve already cleaned. Give the rear cap-to-roof transition seam a heavy scrub—this junction accumulates a waxy, invisible oxidation film from the fiberglass curing in UV and salt spray, and it will wreck sealant adhesion if left in place. Rinse each section thoroughly with clean water and allow the roof to dry completely for at least two hours in warm conditions before you proceed to sealant work. Never use acetone, lacquer thinner, or any petroleum solvent on the fiberglass rear cap—these lift the gel coat and create a chalky, compromised surface. For stubborn old sealant that won’t dissolve, use a plastic putty knife to gently scrape it away; metal scrapers gouge the EPDM membrane on the Transit section and turn your repair into two leak problems. The roof must be bone-dry and at ambient temperature before any sealant touches it.

Step 3: Remove and Replace Failed Sealant at All Penetrations

Isolate each roof penetration and reseal it individually. The Fantastic Fan sits on a raised ABS curb with Dicor applied around its base perimeter—pull away any old, yellowed, or separated Dicor with the plastic putty knife; laying new sealant over failed old Dicor doesn’t work because the new material won’t grab the chalky, degraded surface underneath. Many Ekkos come with the solar roof prep kit, which includes a conduit chase fitting near the rear of the Transit roof section—this one sits overlooked on most roofs and becomes a direct water pipeline into the driver-side wall cavity and electrical chase. Load self-leveling Dicor into the drip-free caulking gun (standard triggers cause this low-viscosity product to ooze and drip uncontrollably; the drip-free version eliminates sag between cuts). Lay down a continuous bead starting at the uphill edge of each fitting and working around the full perimeter. Self-leveling Dicor is designed to flow and settle into low spots without tooling—don’t try to smooth it with a finger or you’ll pull it thin. Apply it at least two inches wide on all sides of every penetration. The Thule awning rail mounting bolts that run along the driver’s side roof edge each need individual Dicor caps applied—lift the awning arm back and inspect and seal each bolt head.

Step 4: Address the Rear Cap-to-Roof Transition Seam

This single seam is the critical failure point on the entire Ekko and the one Winnebago’s factory service manuals specifically call out for annual inspection. The fiberglass composite rear cap extension is fastened and adhered to the Transit’s metal roof, and the transition seam runs horizontally across the roof roughly at the rear-wall sleeping area. The thermal expansion rates of fiberglass and steel differ—this joint moves incrementally with every significant temperature swing, which means it’s a dynamic, living joint that will eventually crack any rigid sealant applied to it. Strip away all existing sealant along this seam using the plastic putty knife, working carefully to avoid gouging the underlying EPDM or fiberglass substrate. When the seam gap widens past a quarter-inch or shows evidence of multiple reseal layers built up over years, reach for EternaBond RoofSeal tape instead of Dicor alone as your primary repair material. EternaBond’s self-adhering butyl layer bonds equally well to fiberglass and EPDM membrane and flexes with joint movement rather than fracturing like rigid sealant. Cut the four-inch tape to length, spanning the full seam plus six inches overlap on each end. Peel back the backing sheet in stages and press it down with firm pressure, then run your J-roller over it multiple times with overlapping strokes to crush out every air pocket and drive full butyl contact into the roof surface. Any lifted or air-backed edge on EternaBond becomes a water entrance—J-rolling is the step that separates a seal that lasts from one that fails in a year. Cap the tape with a bead of self-leveling Dicor over both edges once the tape is fully adhered.

Step 5: Inspect and Reseal the Fantastic Fan Installation

The Fantastic Fan on the Ekko is factory-fitted into a standard 14-by-14-inch opening cut into the Transit roof panel. The fan’s ABS plastic curb comes sealed from the factory with Dicor, but the hinge area where the lid connects and the four corners of the curb are where failures begin. Open the fan lid fully and examine the interior curb surface—rust staining or discoloration on the steel roof pan underneath indicates past or ongoing water entry, which you can verify by checking the headliner from inside the van. Rust marks on the interior ceiling or headliner material around the fan opening mean an active leak has been cycling for more than one season. On the outside, apply fresh Dicor around the entire perimeter of the curb, making the uphill front edge especially wide—at least three inches—since rainwater rushing backward at highway speed concentrates its force on the leading edge of the curb. Examine the four corner bolts anchoring the fan curb to the roof; if any are loose, snug them up before applying sealant because Dicor over a moving fastener won’t stop vibration-driven leaks. Apply only moderate torque—you’re threading into sheet metal and plastic and can easily strip the holes, which then require backing plates to repair. Fresh sealant applied properly seals the gap, but it can’t hold a fastener that’s wiggling underneath.

Step 6: Apply EPDM Roof Coating to the Transit Roof Section

The metal Transit roof panel on the Ekko arrives with a factory coating but gains substantial longevity from a fresh EPDM rubber coating reapplied every three to five years, particularly in strong-UV environments. This coating step applies only to the metal Transit roof portion—skip the fiberglass rear cap, as EPDM won’t bond correctly to gel coat and creates moisture traps beneath the coating surface if applied anyway. Before rolling any coating, apply the Liquid Rubber EPDM/TPO primer using a three-inch roller, covering the entire metal roof section with an even, thin coat. Allow the primer to flash and tack according to the can instructions—typically 30 to 60 minutes contingent on temperature, humidity, and air movement. Primer is the layer that actually locks the EPDM coating to the substrate; skip it and your coating peels or blisters as soon as temperatures drop and the membrane shrinks. Roll the EPDM rubber coating in two thin passes rather than one thick layer; a single heavy coat skins over on top while remaining tacky underneath, which leads to trapped moisture and blistering once ambient temperature drops. Apply the first coat rolling in one direction and the second perpendicular to the first to eliminate roller marks and achieve even coverage. Keep the coating at least two inches clear of any Dicor beads you’ve already laid down—the products are compatible, but overlapping creates an unnecessary thickness transition that can lift and separate at the edges when the roof thermally cycles.

Step 7: Final Inspection, Cure Time, and Water Test

Dicor sealant requires a minimum 24-hour skin-over period and 72 hours of full cure before the van should be driven through rain or subjected to washing. The EPDM coating needs 48 hours minimum between successive coats and 72 hours total before water exposure. Avoid parking under trees during the cure window—bird droppings and leaf acids stain the products and partially inhibit curing on both materials. After cure time has passed, conduct a water test before considering the work finished: hit each sealed seam and penetration with a gentle garden hose stream for two minutes while someone inside watches the ceiling and walls with a flashlight in hand. Begin at the rear cap-to-roof seam and methodically work forward. Focus especially on the forward driver-side roof edge above the inverter compartment—water sneaking in there can track down the interior wall and reach the Xantrex Freedom XC 2000W unit stored in the under-bed compartment without showing obvious ceiling stains, and electrical components sitting in water create serious shock and fire hazards. Mark any interior moisture you discover during the water test and immediately apply fresh sealant to that exterior location before considering the repair complete. Write down the date and exact products used on a card stashed with the Ekko’s owner manuals—your roof service history becomes valuable for resale and helps you track real-world durability of each repair over time.

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Why the Dicor 501LSW-1 Stops the Hairline Crack From Becoming a Ceiling

On the Ekko, those hairline cracks around seams and skylights don’t stay hairline for long—UV exposure and thermal cycling turn them into water highways in a single season. The Dicor 501LSW-1 self-leveling sealant is the repair I actually trust to hold its seal, not harden into a brittle failure point half a year down the road.

What works

• Levels itself after you lay it down, which means imperfect caulk gun technique won’t crack out in six weeks the way rigid sealants inevitably do.
• Stays genuinely flexible once cured, so it stretches and contracts with the roof’s thermal expansion cycles instead of fracturing the first time overnight temps swing 40 degrees.
• Paintable and UV-resistant in white—blends with the existing sealant line instead of standing out as a dark repair that screams “water got in here.”

What doesn’t

• The 10.3 oz cartridge is small—expect to need 2–3 cartridges per full skylight perimeter or roof seam reseal, and you’ll need to own a caulking gun if you don’t already have one on hand.
• Full water-tightness doesn’t happen until 24–48 hours have passed, so this isn’t a quick patch-and-drive repair if you’re on a timeline to leave camp.

I’ve had this sealant fail on me once—and only once—when I tried to apply it over a wet surface and didn’t realize the primer underneath hadn’t fully flashed. Now I verify every prep surface is bone dry before opening the tube. If you’re serious about stopping this leak cycle on your Ekko, grab the Dicor 501LSW-1 EPDM Self-Leveling Lap Sealant, 10.3 oz – White.

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