Flex Seal Liquid rubber coating sealant — 473 ml Black, waterproof flexible UV-resistant protection for roofs, RVs, basements

Flex Seal Liquid is a brush-, roll-, dip- or pour-on liquid rubber that creates a flexible, waterproof, breathable, and UV-resistant coating to seal leaks and protect surfaces.

Whether you're patching a roof, coating an RV seam, protecting basement walls, or waterproofing marine fittings, this 16 oz can of Flex Seal Liquid offers a versatile rubberized barrier. It applies smoothly, dries to a seamless membrane, and resists sun damage while slowing corrosion on metal surfaces. The formula is designed for easy application and bonds to a wide range of materials including EPDM, masonry, metal and more.

How do I apply Flex Seal Liquid for the best waterproof seal?

Surface prep and even application are the keys. Clean the area of dirt, grease, and loose material, allow it to dry, then brush, roll, dip, or pour the product on in thin, even coats for a continuous rubberized film. Multiple thin coats build a more durable membrane than one heavy coat.

• Clean and dry surfaces before application.
• Use a brush or roller for small areas; pour or dip for larger surfaces.
• Allow recommended drying time between coats for best flexibility.
• Mask adjacent areas to prevent overspray or drips.

What surfaces and projects is this product suitable for?

Flex Seal Liquid adheres to many common building and vehicle substrates and works well on roofs, gutters, trailers, RVs, boats, concrete, and metal flashing. It's a practical choice for temporary repairs and longer-term protection where a flexible rubber coating is needed.

• EPDM roofing seams, metal roofs, and asphalt patches.
• Basement walls and masonry to reduce moisture penetration.
• RV seams, trailer joints, hatches, and plumbing penetrations.
• Marine fittings and components where a water-barrier is useful.

How durable and weather resistant is the cured coating?

When fully cured, the coating forms a UV-resistant, flexible rubber layer that helps prevent rust and can stand up to typical outdoor exposure. It remains flexible to accommodate movement in substrates, reducing the chance of cracking, while also offering chemical resistance for many onsite conditions.

• UV resistant to slow sun-related degradation.
• Flexible film to accommodate surface expansion and contraction.
• Helps prevent rust on metal surfaces by sealing out moisture and air.
• Chemical resistance for common household and outdoor chemicals.

How do I choose the right amount and maintain the coating?

A 16 oz can covers small to medium patches and test areas; larger roofs or full-vehicle projects need multiple cans and planning for overlapping passes. Maintain the coating by inspecting periodically and touching up worn or damaged spots to preserve the waterproofing performance.

• A 16 oz can is suited for spot repairs and sample applications.
• Estimate coverage by area and coat thickness; plan multiple coats as needed.
• Inspect annually and recoat high-wear areas to extend service life.

Who is this product for? Flex Seal Liquid 16 oz is aimed at homeowners, DIYers, RV and boat owners, and maintenance professionals who need a simple, adaptable liquid rubber solution for patching leaks, protecting surfaces from moisture and UV exposure, or adding a flexible protective layer. It’s ideal for one-off repairs, seasonal maintenance, and prototype testing where a brush-, roll-, dip- or pour-on rubber coating is preferred. For large commercial jobs, plan product quantities and application method accordingly.