Flex Seal Flex Paste Super Thick Waterproof Rubberized Paste 1 lb. White

Flex Paste is an ultra-thick, waterproof, rubberized sealant that transforms from a paste into a flexible, watertight barrier. Designed for both indoor and outdoor applications, it clings to wet or dry surfaces—even underwater—and cures to a durable, paintable finish that resists cracking, shrinking, and UV damage. Ideal for patching large gaps, cracks, and holes, this versatile adhesive works on virtually any material, making it a go-to solution for DIY, repairs, crafts, and more.

Whether you’re sealing a leaky roof, filling foundation cracks, or tackling hobby projects, Flex Paste delivers long-lasting protection against air and moisture intrusion. Proudly made in the USA, each 1 lb jar comes in a stay-fresh container to lock in sealing power and prevent waste.

Key Features

• Super-thick, rubberized paste seals out air, water & moisture
• Bonds to wet or dry surfaces; can be applied and cured underwater
• Dries to a strong, flexible, paintable barrier—UV resistant
• Won’t shrink, crack, or become brittle; maintains flexibility year-round
• Fills large areas instantly; spreadable, shapeable & sandable
• Works on wood, glass, tile, concrete, metal, brick, PVC, fabric, and more
• Functional cure time: 24–48 hours
• Stay-fresh container prevents air exposure and keeps paste usable

⚠️ WARNING: This product contains chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, visit www.P65Warnings.ca.gov.