Best Sealant for Fiberglass Horse Trailer Roof

ByEquineathon

Fiberglass horse trailers are known for their sleek look, durability, and lighter weight compared to steel. But over time, even fiberglass roofs develop hairline cracks, weakened seams, and potential leaks from UV exposure and weathering. A good sealant is essential to prevent leaks, protect the interior, and extend your trailer’s life. The best sealants for fiberglass horse trailer roofs are flexible, UV-resistant, and designed to bond securely with fiberglass surfaces. In this guide, we’ll highlight the top-rated sealants and explain how to choose the right one for your trailer.

Quick Picks

Buyer’s Guide: Choosing the Right Fiberglass Roof Sealant

Fiberglass roofs have different needs than aluminum or steel. Here’s what to consider:

  • Flexibility: Fiberglass flexes with temperature changes, so your sealant must remain elastic without cracking.
  • Adhesion: Look for RV-grade sealants specifically designed for fiberglass and composite materials.
  • UV Resistance: Sun exposure can quickly break down low-quality sealants, causing leaks and fading.
  • Waterproofing: A good sealant blocks standing water and resists mold growth.
  • Application Style: Self-leveling sealants are perfect for flat surfaces, while non-sag formulas work better on vertical seams.
  • Durability: Premium products should last 5–10 years with proper application.

Detailed Product Reviews

Dicor 501LSW Self-Leveling Lap Sealant

Who it’s for: Horse owners wanting the easiest, most trusted sealant for fiberglass roofs.

  • Key Benefits: Self-leveling; bonds to fiberglass, aluminum, wood, and rubber roofing; UV stabilized.
  • Pros: Easy DIY application, long-lasting, flexible.
  • Cons: Works best on horizontal surfaces; not ideal for vertical seams.

Final Verdict: The go-to fiberglass roof sealant for most horse trailer owners. Check Dicor Sealant.

Geocel Pro Flex RV Flexible Sealant

Who it’s for: Budget-conscious buyers needing a reliable, flexible sealant for fiberglass seams.

  • Key Benefits: Bonds to fiberglass, aluminum, and wood; paintable; UV-resistant.
  • Pros: Affordable, versatile, strong adhesion.
  • Cons: Not self-leveling; requires careful application for smooth results.

Final Verdict: A budget-friendly option that still delivers quality results. See Geocel Pro Flex.

Eternabond RoofSeal Tape

Who it’s for: Owners looking for premium, permanent sealing without messy caulk lines.

  • Key Benefits: MicroSealant technology; UV-stable backing; designed for fiberglass, aluminum, and EPDM.
  • Pros: Very durable, quick application, long lifespan.
  • Cons: More expensive; less flexible for tight corners.

Final Verdict: The premium choice for maximum leak protection. Check Eternabond Tape.

Sikaflex-221 Polyurethane Sealant

Who it’s for: Owners needing a strong, multipurpose adhesive sealant.

  • Key Benefits: Bonds to fiberglass, wood, aluminum, and steel; UV-resistant; flexible and paintable.
  • Pros: Industrial strength, versatile, long-lasting adhesion.
  • Cons: Slower curing time; messier to apply.

Final Verdict: Excellent for structural sealing and patch jobs. See Sikaflex-221.

3M Marine Adhesive Sealant 4000UV

Who it’s for: Horse owners in hot or coastal climates needing UV- and salt-resistant sealing.

  • Key Benefits: UV-resistant; waterproof; removable if needed (unlike 5200 version).
  • Pros: Strong adhesion, marine-grade durability, flexible.
  • Cons: Higher price than RV-specific sealants.

Final Verdict: Great for trailers exposed to harsh weather. Check 3M 4000UV.

Henry Tropi-Cool 100% Silicone Roof Sealant

Who it’s for: Owners wanting full-roof reflective coating for cooling and waterproofing.

  • Key Benefits: 100% silicone; UV reflective; waterproof; ideal for fiberglass.
  • Pros: Lowers trailer heat, long-lasting, easy to apply with a roller.
  • Cons: Better for large surface coverage than seams.

Final Verdict: Best for heat control and full-roof sealing. See Henry Tropi-Cool.

Comparison Table

Product Type Best For Flexibility Price Range
Dicor 501LSW Self-leveling Horizontal seams High $$$
Geocel Pro Flex Flexible caulk Budget sealing High $$
Eternabond RoofSeal Sealant tape Premium sealing Medium $$$$$
Sikaflex-221 Polyurethane Structural & seams High $$$$
3M 4000UV Marine adhesive UV/salt exposure High $$$$
Henry Tropi-Cool Silicone coating Full roof coverage High $$$

FAQ Section

  • Do fiberglass trailer roofs need special sealant? Yes—use RV- or marine-grade sealants designed for fiberglass and UV resistance.
  • What’s the difference between self-leveling and non-sag? Self-leveling is best for flat seams, while non-sag is ideal for vertical joints.
  • How often should I reseal a fiberglass trailer roof? Inspect yearly and reseal every 3–5 years or as needed.
  • Can I use marine sealant on a horse trailer? Yes—marine-grade sealants like 3M 4000UV work great for fiberglass trailers.
  • What’s the easiest product to use? Self-leveling sealants and roof tapes are easiest for DIY applications.

Conclusion

Sealing a fiberglass horse trailer roof is crucial for keeping your trailer watertight and long-lasting. For most owners, Dicor 501LSW offers the best balance of performance and ease of use. For budget buyers, Geocel Pro Flex provides dependable sealing at a low cost. And for premium, long-term sealing, Eternabond RoofSeal Tape delivers unmatched durability. With the right sealant, you’ll keep your horses dry, your trailer safe, and your investment protected. Shop the best fiberglass roof sealants today and safeguard your horse trailer.