Liquid Rubber Waterproof Sealant – DIY Leak Repair for Flat & Low-Slope Roofs, Foundations, Gutters | Black | 5 Gallon

Overview

Liquid Rubber Waterproof Sealant creates a seamless, rubberized membrane that blocks water intrusion on flat and low-slope roofs, foundations, gutters, concrete surfaces, planter boxes, and more. The dark, pliable coating smooths over uneven areas and forms a durable barrier that remains flexible as the building moves and temperatures shift.

Designed for both professionals and DIYers, this 5-gallon black coating is meant to outperform traditional tar or patch products by delivering reliable adhesion, weather resistance, and a forgiving, rubberized finish that is comfortable to apply in a variety of spaces.

Key benefits

• Seamless waterproof membrane across flat and low-slope surfaces
• Elongation over 950% to accommodate movement and temperature changes
• Water-based formulation with no VOCs or harsh odors for indoor/outdoor use
• Easy to apply by brush, roller, or spray, suitable for confined spaces
• Bridges joints with seam tape or Geo-Textile to create a complete waterproofing system
• Trusted by professionals and DIYers with millions of gallons sold
• Caution: not intended for heavily trafficked walking surfaces

Coverage, use, and system setup

• Flat/low-slope roofs and standing water: 1 gallon covers about 15 sq ft per coat (3–4 coats to reach 60–80 mils)
• Vertical surfaces like foundations: 1 gallon covers about 30 sq ft per coat (2–3 coats for ~30 mils)
• Apply by brush, roller, or spray; ideal for roof repair and preventive waterproofing
• Use in tandem with Liquid Rubber Seam Tape or Geo-Textile to bridge joints and protrusions

Safety, materials, and use cases

As a water-based formula, it minimizes odors and avoids damage to sensitive materials like foam insulation. It bonds well to metal, concrete, wood, and other common substrates, making it versatile for a range of leak-prone areas. While highly effective, it is best suited for areas with minimal foot traffic where a protective surface is not required for walking.