So apparently my brilliant predecessor thought maintenance was optional on my 2001 Rexhall Rexair 36-footer. The fiberglass roof now has more character than I bargained for - complete with artistic crack patterns and some questionable looking penetrations around the vents and antenna mounts.
I'm ready to tackle this project before my RV turns into an expensive lawn ornament (or worse, a really awkward swimming pool). I've heard Dicor products mentioned in hushed, reverent tones around RV parks, but I have no clue what I'm actually doing here.
What's the proper order of operations for fixing this fiberglass roof disaster? Do I need special products for the cracks versus the sealant areas? I'd rather not learn expensive lessons the hard way!
For fiberglass roof repair, clean thoroughly, fix cracks with gelcoat kit, and seal penetrations with Dicor 501LSW. Address structural issues before cosmetic coating.
Welcome to the RV community! For your 2001 Rexhall Rexair's fiberglass roof, Dicor products are absolutely the right choice - they're the gold standard for RV roof maintenance. Your instincts are spot-on here. Dicor Self-Leveling Lap Sealant and their Non-Sag Sealant are specifically formulated for RV applications and will bond excellently to your fiberglass roof. Given that you have a 23-year-old coach, you'll likely need both products plus their cleaning and prep solutions for a proper restoration job.
On a 2001 Rexhall Rexair, the most common roof issues you'll encounter include cracked or shrinking sealant around vents, air conditioning units, and antenna mounts. The original butyl tape and sealants have likely hardened and lost adhesion after two decades of UV exposure and temperature cycling. You might also find stress cracks in the fiberglass itself, particularly around mounting points where flexing occurs during travel.
California's intense UV exposure accelerates roof degradation, so don't be surprised if you find more widespread sealant failure than expected. The gelcoat on your fiberglass roof may also show oxidation or chalking, which needs addressing before applying new sealants. Water intrusion points are typically found where different materials meet - like where rubber boots seal around pipes or where metal fixtures mount to the fiberglass.
Start with a cleaner appropriate for fiberglass roofs to remove dirt, oxidation, and old wax buildup. Remove all old, loose sealant using a plastic scraper and heat gun on low setting. Never use metal tools that could scratch your gelcoat. Clean the entire roof surface and let it dry completely - this is crucial in LA's dusty environment.
Inspect every penetration point carefully with a flashlight, looking for signs of water damage or soft spots in the underlying structure. Take photos before you start so you remember where everything goes. Gather all your materials first: Dicor Self-Leveling Lap Sealant for horizontal seams, Non-Sag Sealant for vertical applications, cleaning supplies, and basic tools. Plan for a full weekend - rushing roof work leads to callbacks and potential water damage.
Check the weather forecast and avoid working within 24 hours of rain. California's sudden weather changes can ruin uncured sealant. Have a plan to cover any open penetrations if unexpected weather hits. Remove or cover your solar panels if equipped, and clean out all roof drains and gutters while you're up there.
Begin by removing all old sealant from around every roof penetration using your heat gun and scraper. Work systematically from front to back, cleaning each area thoroughly with the Dicor cleaner. For your Rexair's roof vents, remove the entire assembly if possible - this gives you much better access and ensures a proper seal when reassembled. First disconnect power to any powered vents and note electrical connections and mounting hardware positions before removal.
Apply Dicor Self-Leveling Lap Sealant to all horizontal seams and around the base of fixtures where water pools. This product will flow and self-level, creating a smooth, watertight seal. Use the Non-Sag formula for vertical surfaces like vent sidewalls and anywhere gravity would cause regular sealant to droop. Apply in temperatures between 40-100°F for best results.
Work in sections, allowing each area to skin over before moving to the next. Don't try to tool or smooth Dicor sealants - they're designed to cure naturally. For the AC unit, you'll likely need 2-3 tubes of sealant given its size. Pay special attention to the rear corners where stress cracking commonly occurs on Rexhall coaches.
After sealing, consider applying Dicor's roof coating for added protection. This white elastomeric coating reflects UV rays and provides an additional waterproof layer. It's particularly beneficial in California's intense sun. Allow 24-48 hours cure time before exposing to moisture, and avoid walking on freshly sealed areas for at least a week.
Call in professionals if you discover structural damage like soft spots in the roof decking or extensive delamination - these issues require specialized repair techniques and materials. If you find evidence of long-term water intrusion with interior damage, you'll want an RV service center to assess the full extent of repairs needed, especially given the age of your coach.
Consider professional help if you're uncomfortable working at height on a tall coach. Always use proper fall protection equipment including safety harnesses when working on any RV roof, or if you discover the roof membrane itself needs replacement rather than just resealing. Some RV service centers in the LA area specialize in roof work and can complete the job faster with warranty coverage. However, basic resealing with Dicor products is well within DIY capability for most RV owners, and you'll save significant money doing it yourself.
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