WINNEBAGO SOLIS – Roof Seal and Skylight Maintenance

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Roof Seal and Skylight Maintenance for WINNEBAGO SOLIS

The Winnebago Solis sits on a Ram ProMaster 2500 platform, and its roof assembly has two distinct water intrusion risks that every owner needs to understand: the Maxxair 7500K vent flange and — on 59P pop-top models — the full-perimeter canvas-to-hardtop seam that wraps the entire roof edge. Unlike a traditional fiberglass RV roof, the Solis uses the ProMaster’s factory steel roof with an applied membrane layer, meaning small cracks in lap sealant around the vent flange can track water a surprising distance before you ever see a drip inside. Budget a full day for this job the first time through, and plan to inspect at minimum twice a year — once before summer UV exposure peaks, and once before winter storage.

Required Parts

Step-by-Step Instructions

Step 1: Safety Setup and Roof Access

Before climbing on the roof, disconnect shore power at the 15-amp inlet on the driver-side rear of the van — do not just unplug the campground pedestal end, unplug the van inlet itself. The Xantrex Freedom XC 1000W inverter/charger under the driver-side bed will continue drawing from batteries even with shore power off, but there are no active roof-mounted electrical components that create shock hazards during this job as long as shore power is physically unplugged. Use a ladder rated for your weight plus 30 pounds of tools, positioned at the rear of the ProMaster against the ladder bumper — the ProMaster’s rear corners are reinforced and accept ladder feet without damaging the body. Wear rubber-soled shoes with no heel; the ProMaster roof steel is slippery when dusty. Walk only on the structural ribs — you can feel them as raised ridges running laterally across the roof. Avoid stepping between ribs on flat membrane spans. Lay down a moving blanket or foam kneeling pad to distribute your weight and protect the membrane while you work. On 59P pop-top models, the pop-top mechanism is spring-assisted — make sure it is fully latched down and locked before putting any weight near the perimeter seam area.

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

Start your inspection at the Maxxair 7500K vent, which is mounted roughly centered on the roof slightly toward the rear of the van. Run a gloved finger around the entire perimeter of the vent flange where the white self-leveling lap sealant meets the membrane. You are feeling for sealant that is cracked, lifted at the edges, bubbled, or has shrunk away from the flange lip — any gap wider than a business card is a water intrusion point. Next, walk the perimeter of the ProMaster roof rail, inspecting where the factory drip rail meets the sidewall. On 59P models, shift your attention to the canvas-to-hardtop seam: unzip the pop-top several inches at each corner and look for canvas delamination, fraying at the stitch line, or hardtop flange areas where sealant has cracked. Photograph every suspect area with your phone before touching anything — this gives you a baseline and helps you confirm repairs held at the next inspection. Also check the area around any Thule HideAway 1200 awning mounting brackets on the driver side; the bolts penetrate the ProMaster drip rail and are a secondary leak point that is often missed. Mark all problem spots with blue painter’s tape so nothing gets missed during repair.

Step 3: Clean and Degrease the Entire Roof Surface

Proper adhesion of every product in this job — sealant, tape, and coating — depends on a surgically clean surface. Start by dry-brushing loose dirt and debris off the membrane using a soft-bristle brush, working from front to back so debris falls off the rear. Pour a generous amount of the Dicor rubber roof cleaner and degreaser into a bucket diluted per label directions — typically 1:4 with water for general cleaning, full-strength for oily or heavily oxidized spots. Apply with a soft mop or sponge, scrubbing in sections. Pay extra attention to the ring of old sealant around the Maxxair 7500K flange — oxidized EPDM membrane develops a chalky gray residue that acts as a release layer and will prevent new sealant from bonding if not removed. Rinse with clean water from a garden hose and let dry completely — surface must be dry to the touch with zero moisture trapped under any lifted membrane edges before you apply any new product. On hot days, 30 minutes of dry time is usually sufficient; in humidity above 70%, allow at least 90 minutes. Do not use petroleum-based solvents or acetone on EPDM membrane — they cause swelling and delamination.

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

Use the plastic putty knife — not a metal scraper — to lift and peel away all existing sealant around the Maxxair 7500K vent flange. The plastic blade flexes enough to get under cracked sealant without gouging the membrane or scratching the aluminum flange. Work slowly around all four sides of the square vent frame; Winnebago applies a generous bead from the factory, and it often layers over itself from previous service. Remove every bit of old material down to bare flange and clean membrane — any old sealant left under the new layer creates a bond failure point. Wipe the cleaned area with a dry cloth. Load the self-leveling Dicor lap sealant into the drip-free caulking gun and cut the tip at a 45-degree angle to produce a bead approximately 3/8 inch wide. Apply a continuous bead starting at a rear corner of the vent flange and work around the entire perimeter, slightly overlapping your start point. Self-leveling Dicor will flow and settle on its own on a horizontal surface — do not tool it with your finger or a putty knife, as this introduces air pockets. Apply a second bead 1 inch outboard of the first, overlapping slightly, to ensure full coverage of the flange-to-membrane transition. Allow 24 hours cure time before exposing to rain.

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

EternaBond RoofSeal tape is your heavy-duty reinforcement layer for seams that have chronic movement or that self-leveling sealant alone cannot hold long-term — specifically the ProMaster drip rail seam at the roof edges and the awning bracket penetration points on the driver side. Cut the 4-inch wide tape into lengths using sharp scissors — measure each run before cutting. For the drip rail seam, cut lengths to span each side of the roof from front to back in one continuous piece where possible to minimize overlap joints. Peel back the first 6 inches of the release liner, align the tape centered over the seam, and press firmly with your thumb before pulling the liner away — do not peel the entire liner at once or the tape will fold onto itself. Once positioned, use the J-roller with firm, overlapping strokes along the entire tape run to press it to full adhesion — this step is not optional. The J-roller eliminates air pockets that cause tape edges to lift in heat cycles. At awning bracket bolt heads, cut small patches of EternaBond large enough to cover the bolt head plus 2 inches of clearance in all directions. Apply primer from the Liquid Rubber EPDM/TPO primer can under any tape that overlaps existing coating rather than bare membrane for best adhesion.

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

This step applies only to the Solis 59P with the pop-top roof — skip to Step 7 if you have a fixed-roof model. The canvas-to-hardtop perimeter seam is the single highest water intrusion risk on the entire vehicle, and it is the most commonly neglected. Lower the pop-top to the fully closed and latched position. Working around the perimeter, closely examine where the vinyl-coated canvas edge is attached to the fiberglass hardtop flange. Winnebago bonds this seam with an adhesive track and often a secondary sealant bead. If you see any lifted canvas edge, delaminated adhesive, or gaps in the sealant bead, those are your active leak paths. Do not try to fold or pry the canvas back aggressively — the vinyl is bonded in place and tearing it is expensive. For small gaps in the sealant bead at the hardtop flange only, apply a thin bead of self-leveling Dicor lap sealant into the gap and let it wick in before applying a finishing bead over the top. For any section where canvas has lifted more than a half inch from the flange, use a flexible outdoor canvas adhesive — not the Dicor — to re-bond the canvas edge, then seal over the adhesive joint with a thin Dicor bead once the adhesive has cured per its label. Inspect all four corners twice; corners are where the canvas develops stress cracks first.

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

EPDM roof coating is the final protective layer that extends the life of the underlying membrane by reflecting UV and sealing micro-cracks before they grow. Before coating, ensure all Dicor sealant from Steps 4 and 5 has cured at least 24 hours and all EternaBond tape edges are fully pressed down with the J-roller. Apply the Liquid Rubber EPDM/TPO primer to the entire roof surface using the 3-inch paint roller — a thin, even coat, not a thick buildup. The primer chemically bonds to the existing membrane and gives the EPDM coating something to grip. Allow primer to dry until it is not tacky to the touch — typically 45 to 60 minutes in warm weather. Pour the EPDM rubber roof coating into a roller tray and apply the first coat using the 3-inch roller with slow, overlapping strokes. Work from the front of the roof to the rear so you are always rolling toward your exit point and not walking on wet coating. Apply two full coats, allowing the first coat to dry until firm before applying the second — usually 2 to 4 hours depending on temperature and humidity. Avoid coating in direct sun above 90°F as the product skins over too fast. Keep the Maxxair 7500K vent lid open slightly to prevent coating from sealing the vent gasket to the frame. Final cure before driving or rain exposure: 24 hours minimum, 48 hours preferred.

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