Flex Seal Liquid Rubber Coating Sealant - Waterproof Roof & RV Repair

In this review the reviewer looks at Flex Seal Liquid, a brushable, rollable and pourable liquid rubber meant for sealing leaks and protecting surfaces. The bottom line is that this product is best for DIYers who need a quick, watertight, flexible coating for outdoor and portable applications because it goes on smooth, adheres to common materials and provides a UV resistant, moisture-blocking layer. The review focuses on ease of use, where it performs well, and realistic limits based on customer experiences and the product description.

Key Features

• Liquid rubber in a can: Can be brushed, rolled, dipped or poured to create a continuous rubberized layer on irregular surfaces.
• Watertight seal: Designed to seal out water, air and moisture so it can stop leaks around roofs, basements and outdoor fixtures.
• Fast coverage: Goes on smooth and covers quickly, reducing application time for larger surfaces or patch repairs.
• UV resistant: Formulated to resist sunlight degradation so outdoor repairs last longer under sun exposure.
• Rust and chemical resistance: Helps prevent rust and corrosion and tolerates exposure to common chemicals in outdoor use.

Who It's For

Flex Seal Liquid is aimed at homeowners, RV and boat owners, and hobbyists who need a versatile, waterproof coating they can apply without specialized equipment. It is particularly useful for sealing metal roofs, repairing outdoor fountains, coating masonry patches, or applying a protective layer to EPDM and trailer seams.

It is less suitable for precision structural repairs where engineered sealants or professional membrane systems are required, or for users expecting a permanent factory-level finish; some customers report the coating may begin to peel over long periods in high-wear areas, so heavy-traffic or constantly flexing joints may need alternative solutions.

Pros & Cons

Pros

• Easy to apply by brush, roller or pour which makes it accessible to DIYers and quick small repairs.
• Provides a flexible, waterproof barrier that effectively stopped leaks in reported outdoor fountain and metal roof fixes.
• UV resistant and helps prevent rust and corrosion, extending the life of exposed surfaces.

Cons

• May not be permanent in high-wear or highly flexible areas for multi-year service, with some reports of peeling after about a year.

Specifications

Product type	Liquid rubber coating
Application methods	Brush, roll, dip or pour
Primary benefits	Waterproofing, flexibility, UV resistance
Surface uses	Roofs, basements, RVs, campers, trailers, marine, EPDM, masonry
Chemical properties	Chemical resistant; prevents rust and corrosion
Container size	32 oz
Finish	Clear rubberized coating

Our Verdict

Flex Seal Liquid is a practical, user-friendly option for homeowners and vehicle owners who need a flexible waterproof coating applied quickly without special tools. It delivers good coverage, UV protection and rust resistance at a reasonable value, though those needing a long-term structural membrane or heavy-traffic durability should consider more permanent professional systems.

Frequently Asked Questions

Can this be applied over metal roofs?
Yes; customers have used it to stop leaks on metal roofs and the product is formulated to prevent rust and create a watertight layer.

How can it be applied?
It can be brushed, rolled, dipped or poured, giving flexibility for small patches or larger coated areas.

Is the finish UV resistant?
Yes, the formulation is UV resistant to help outdoor applications last longer under sun exposure.