WINNEBAGO SOLIS – Roof Seal and Skylight Maintenance

Roof Seal and Skylight Maintenance for WINNEBAGO SOLIS

I’m on my back under the Maxxair 7500K vent with a flashlight between my teeth, running my thumb along where the white lap sealant meets the membrane, feeling for the telltale separation that means water’s been pooling there for weeks. On the Winnebago Solis — especially the 59P pop-tops — this exact spot and the canvas-to-hardtop perimeter seam are where trouble always hides. What started as a hairline crack in the lap sealant has already been silently feeding moisture across the ProMaster’s factory steel roof for who-knows-how-long before a single drip appears inside the living space. The steel roof on this platform doesn’t shed water like traditional fiberglass does — it pools and tracks it sideways — so by the time you notice anything, the damage underneath is usually triple what the outside tells you. This guide walks you through the exact inspection and repair sequence so you catch it early and stay ahead of it on your own schedule.

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: Safety Setup and Roof Access

Unplug the driver-side 15-amp inlet from the van body before you touch anything on the roof — don’t just disconnect the campground pedestal, physically disconnect the van inlet itself. The Xantrex Freedom XC 1000W inverter/charger mounted under the driver-side bed continues pulling from the battery bank even after shore power cuts off, but there are no energized electrical parts on the roof itself as long as shore power is physically removed from the inlet. Position your ladder at the rear corner near the ladder bumper — the ProMaster’s rear corners are reinforced and will take a ladder without damage. Wear rubber-soled shoes with no heel grip; the ProMaster’s steel roof becomes slippery the moment dust settles on it. Keep your feet on the structural ribs — you can feel them as raised lines running side to side across the roof. The flat membrane areas between ribs cannot safely support your full weight. Spread a moving blanket or foam pad underneath you to spread your weight and protect the membrane while you work. If you have a 59P pop-top, make absolutely sure it’s fully closed and locked down before you put any weight anywhere near the perimeter seam.

Step 2: Inspect the Full Roof Membrane and Identify Problem Areas

Begin at the Maxxair 7500K vent — it sits roughly centered on the roof, slightly back from the middle. Wearing gloves, trace your finger around the entire outer edge where the white self-leveling lap sealant touches the membrane. Feel for sealant that has cracked, pulled back from the flange, developed bubbles, or shrunk inward — if the gap is wider than a business card, water is getting in. Next, inspect the ProMaster’s perimeter rail where it meets the sidewall, following the roofline all the way around. On 59P models, unzip the pop-top canvas a few inches at each corner and look for canvas that is coming unglued, fraying where the stitches are, or hardtop flanges where sealant is cracked. Snap photos of every questionable spot with your phone before you touch it — this creates a before-and-after record and helps you validate that repairs hold at your next inspection. Check around any Thule HideAway 1200 awning bracket bolts on the driver side too; those bolts go through the drip rail and are a forgotten leak source. Use blue painter’s tape to flag every problem area so you don’t skip anything when you start fixing.

Step 3: Clean and Degrease the Entire Roof Surface

Everything you install — sealant, tape, protective coatings — depends on starting with a completely clean surface. Dry-brush all the loose dirt and debris off the membrane first using a soft-bristled brush, working front-to-back so dust falls off the rear end. Mix the Dicor rubber roof cleaner and degreaser in a bucket according to label directions — usually 1 part cleaner to 4 parts water for routine cleaning, straight strength for heavily oxidized or greasy patches. Apply with a soft mop or large sponge, working section by section. The ring of old sealant around the Maxxair 7500K gets special attention: oxidized EPDM develops a chalky gray coating that prevents new sealant from sticking if you don’t remove it. Rinse thoroughly with a garden hose and allow complete air-dry — the surface must be bone-dry with no trapped moisture under any lifted membrane sections before you apply new product. On a hot day, 30 minutes usually works; when humidity is running 70% or higher, budget at least 90 minutes of drying time. Steer clear of petroleum solvents and acetone on EPDM membrane — they cause the rubber to swell and peel apart.

Step 4: Remove Old Sealant and Re-Seal the Maxxair Vent Flange

Use the plastic putty knife — not metal — to lift and scrape away all the old sealant from around the Maxxair 7500K vent flange. The plastic blade is flexible enough to get underneath cracked sealant without damaging the membrane or scratching the aluminum frame. Take your time going around all four sides of the square vent; Winnebago installs a thick factory bead, and it often has multiple layers from past repairs. Strip every scrap of old material until you reach bare flange and clean membrane — sealant left underneath the new layer will cause the new bond to fail. Wipe everything down with a clean, dry cloth. Insert the self-leveling Dicor lap sealant into the caulk gun and cut the tip at a 45-degree angle to produce a bead roughly 3/8 inch wide. Start at one rear corner of the vent and lay down a continuous bead around the entire frame perimeter, slightly overlapping where you started. Self-leveling Dicor will flow and settle on its own across a horizontal surface — resist the urge to smooth it with your finger or a tool, as that traps air bubbles. Run a second bead 1 inch outboard of the first, overlapping slightly, to guarantee full flange-to-membrane coverage. Give it 24 hours of cure time before rain or water tests.

Step 5: Apply EternaBond Tape to High-Risk Seams and Awning Mount Points

EternaBond RoofSeal tape is your reinforcement layer for seams that move too much or that sealant alone can’t hold indefinitely — specifically the ProMaster drip rail at the roof perimeter and the awning bracket bolt holes on the driver side. Using sharp scissors, cut the 4-inch wide tape into measured lengths — size each piece before you cut. For the drip rail seam, cut single continuous lengths that run the full side-to-side distance whenever possible to reduce overlapped joints. Peel back only the first 6 inches of the release liner, position the tape centered on the seam, and press hard with your thumb before peeling the rest of the liner away — pulling the entire liner at once causes the tape to fold and stick to itself. After positioning, use the J-roller with firm, overlapping strokes along the whole tape run to achieve full bonding — this is not optional. The J-roller removes air pockets that cause tape edges to lift and separate during heating cycles. At awning bracket bolt locations, cut small tape squares large enough to cover the bolt head and extend 2 inches in all directions. For tape that overlaps any existing roof coating rather than bare membrane, apply a coat of Liquid Rubber EPDM/TPO primer underneath for stronger adhesion.

Step 6: Address the Pop-Top Canvas Perimeter Seam (59P Models Only)

This step is only for Solis 59P owners with the pop-top roof; skip ahead to Step 7 if your rig has a fixed roof. The canvas-to-hardtop seam at the perimeter is your biggest water entry risk on the whole vehicle, and it’s almost universally ignored. Close the pop-top all the way and lock it down. Go around the perimeter and examine where the vinyl-coated canvas attaches to the fiberglass hardtop flange. Winnebago uses an adhesive track for this bond and sometimes adds a secondary sealant bead. If you spot any lifted canvas, adhesive separation, or gaps in the sealant bead, those are your active leak routes. Avoid aggressive folding or prying on the canvas — it’s bonded in place and tearing it costs real money. When the gap is only in the sealant bead at the hardtop flange, apply self-leveling Dicor lap sealant into the gap to let it soak in, then finish with another bead on top. If canvas has lifted more than half an inch from the flange, use a flexible exterior canvas adhesive — not Dicor — to re-bond the canvas edge, then seal the adhesive joint with a thin Dicor bead once the adhesive has set per instructions. Check every corner twice; canvas stress cracks always begin at corners first.

Step 7: Apply EPDM Roof Coating for Long-Term UV Protection

EPDM roof coating is the final protective shell that extends membrane life by blocking UV rays and sealing minor cracks before they expand into major leaks. Before you coat anything, confirm that all Dicor sealant from Steps 4 and 5 has been curing for a full 24 hours minimum and that all EternaBond tape edges are completely compressed with the J-roller. Apply the Liquid Rubber EPDM/TPO primer across the entire roof surface with the 3-inch paint roller — aim for a thin, uniform coat, not a thick heavy layer. The primer creates a chemical bond to the existing membrane and gives the EPDM coating a surface to grab. Wait until the primer is no longer tacky to touch — in warm weather this typically takes 45 to 60 minutes. Pour the EPDM rubber roof coating into a roller tray and apply the first coat with the 3-inch roller, using slow overlapping strokes. Roll from front to rear so you are always moving toward your exit and never stepping on wet coating. Lay down two complete coats, allowing the first to dry until firm before the second — usually 2 to 4 hours depending on air temperature and humidity. Avoid working in direct sun when it’s hotter than 90°F; the product skins over too quickly. Keep the Maxxair 7500K vent lid cracked open to prevent coating from bonding the gasket to the frame. Allow a minimum 24-hour cure time before driving or rain — 48 hours is better.

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The Sealant That Actually Stays Put on a Solis Roof Flange

The Maxxair 7500K vent flange on a Solis doesn’t fail because of the vent itself — it fails because the original lap sealant hardens, cracks, and lets water find every seam underneath. You need a sealant that self-levels and stays flexible in temperature swings, not one that turns into concrete.

What works

• Self-levels as it cures, so you don’t have to feather it perfectly — it fills gaps you can’t see and won’t crack when the roof expands and contracts.
• Stays tacky longer than fast-set alternatives, giving you time to adjust the flange position if you find it sitting crooked after you’ve already caulked.
• One tube covers a typical vent flange replacement with material left over for touch-ups; the white color blends with factory EPDM roof coatings.

What doesn’t

• Takes 24–48 hours to fully cure, which means you can’t run water through that vent or expect a watertight seal the same day you install it.
• If you mess up the application and the sealant skins over before you smooth it, you’ll have to dig it out and start over — there’s no reworking half-cured lap sealant.

I once had a Solis where the flange was slightly raised on one corner and I didn’t catch it until the sealant had started setting; I thought I’d wasted the tube and the install, but the self-leveling property actually pulled the sealant down and sealed anyway. Order the Dicor 501LSW-1 EPDM Self-Leveling Lap Sealant, 10.3 oz – White in advance — if you’re doing this repair, you’re already behind.

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