Flex Seal Liquid Rubber Coating Sealant, Waterproof Roof Repair

In this review the Flex Seal Liquid rubber coating is evaluated as a versatile waterproofing product for homeowners, RV owners and small contractors. The single biggest reason to consider it is its delivery format: liquid rubber in a can that can be brushed, rolled, dipped or poured, which makes applying a continuous, flexible barrier straightforward for patching roofs, basements, trailers and marine surfaces. The review reflects hands-on impressions of ease of application, visible finish and the tradeoffs seen in long term adhesion reports.

Key Features

• Liquid rubber delivery: The can formulation allows brushing, rolling, dipping or pouring to form a continuous flexible membrane over joints and seams.
• Watertight seal: Goes on smooth and covers fast, creating a barrier that seals out water, air and moisture for leak prevention.
• UV resistant finish: Built-in UV resistance helps reduce sun-related degradation on exposed roofs and RV surfaces.
• Rust and chemical resistance: The coating helps prevent rust and corrosion on metal substrates and resists certain chemical exposure.
• Flexible and breathable: The cured rubber remains flexible to accommodate thermal movement while allowing trapped moisture to escape.

Who It's For

This product is best for homeowners tackling patch repairs on asphalt, EPDM and masonry surfaces, RV and trailer owners needing a quick waterproof barrier, and marine users looking for a flexible coating that repels water. It is especially useful when a single product that can be brushed or poured simplifies application on irregular surfaces.

Those who require a factory-grade, load-bearing roofing membrane or need guaranteed decades-long adhesion on every substrate should consider professional membranes or contractor-installed systems instead, since some users report peeling or cracking over long service periods on certain surfaces.

Pros & Cons

Pros

• Creates a waterproof, rubberized barrier that is easy to apply with a 3 in brush or roller.
• Versatile application methods allow brushing, rolling, dipping or pouring for different repair needs.
• Provides UV resistance and helps prevent rust and corrosion on metal areas.
• Goes on smooth and covers fast, reducing time spent on smaller repair jobs.

Cons

• Some long-term users report issues with peeling and cracking in certain conditions, so surface prep and follow-up monitoring are important.
• Not a replacement for a full professional roof replacement when structural integrity is the concern.

Specifications

Product type	Liquid rubber coating sealant
Primary uses	Roof repair, basements, RVs, campers, trailers, marine, masonry
Application methods	Brush, roll, dip or pour
Key properties	Waterproof, flexible, breathable, UV resistant
Packed size	1 gallon
Color	Gray

Our Verdict

Flex Seal Liquid is a practical, easy-to-use liquid rubber for spot repairs and preventative waterproofing where flexibility and fast coverage matter. It represents good value for DIYers and RV owners who need a straightforward waterproof barrier, but anyone seeking a permanent, heavy-duty roofing replacement should view this as a repair-grade coating rather than a full roof solution.

Frequently Asked Questions

Can it be applied with a brush?
Yes. The product is formulated to be brushed, rolled, dipped or poured, and many users find a 3 in brush works well for edges and seams.

Is the cured coating UV resistant?
Yes. The formula includes UV resistance to reduce sun-related degradation on exposed surfaces.

Will it prevent rust on metal?
It helps prevent rust and corrosion by forming a protective rubberized layer, though proper surface prep improves adhesion and longevity.