Flexowall Membrane – High-Performance SBS Modified Waterproofing for Vertical & Below-Grade Applications

Advanced Protection for Structural Waterproofing

Flexowall Membrane is a 5mm thick, high-performance waterproofing solution, engineered with SBS (styrene-butadiene-styrene) modified bitumen and reinforced with 180 g/m² thermally bonded polyester-glass for exceptional dimensional stability and tear resistance. This advanced membrane is designed to withstand the toughest environmental conditions, ensuring long-lasting waterproofing performance in below-grade and vertical applications.

The top surface is finished with sand, providing enhanced durability, while the underside features a high-density polyethylene (HDPE) burn-off film, designed to melt during heat application, forming a seamless bond to the substrate for superior water resistance.

Applications

Flexowall is specifically engineered for:
✔ Vertical waterproofing – Ideal for foundations, retaining walls, and blind-side applications.
✔ Tanking systems – Provides robust waterproofing for both interior and exterior walls.
✔ Heavy-duty below-grade protection – Effectively prevents water ingress in underground structures.

Key Features & Advantages

✔ SBS-Modified for Maximum Durability – Ensures flexibility, resilience, and long-term waterproofing.
✔ Proven Performance – Backed by over 40 years of successful application in the construction industry.
✔ Superior Adhesion – Creates a watertight seal when applied to concrete and structural surfaces.
✔ High Penetration Resistance – Protects against water intrusion, soil pressure, and environmental wear.
✔ Seamless Torch-Welded Installation – Ensures quick and effective application with propane torch welding.
✔ One-Layer Efficiency – A single 5mm layer of Flexowall provides superior waterproofing compared to multiple layers of conventional reinforced membranes.
✔ Enhanced Stability & Tear Strength – Reinforced with 180 g/m² polyester-glass for added strength and resistance to deformation.

Packaging & Coverage

  • Roll Dimensions: 3.28′ x 24.6′ (1m x 7.5m)
  • Weight: 97 lbs. (44 kg) per roll
  • Coverage: 70.85 square feet per roll, with 4” side overlaps and 6” end overlaps
  • Packaging: Rolls are palletized and shrink-wrapped, with 23 rolls per pallet

Installation & Surface Preparation

Substrate Preparation

  • Ensure the surface is clean, dry, and free of loose materials, dust, oils, or contaminants that may affect adhesion.
  • For optimal adhesion on vertical surfaces, apply a water-based bituminous primer.

Application Process

  • Torch-Welded Installation: The HDPE burn-off film on the underside melts when heated, creating instant adhesion to the substrate.
  • Alignment & Overlaps: Roll out the membrane, ensuring 4″ vertical side laps and 6″ horizontal end laps.
  • Uniform Heating: Apply even heat across the back surface until it reaches optimal adhesion temperature and achieves a slight sheen.
  • Ensure Proper Sealing: A 1/4” (6.5 mm) bitumen flow-out must be visible at seam areas.
  • Roller Method: A weighted roller or hand roller can be used to enhance bonding at the seams.

Detailing & Complex Areas

  • Use Flexobit for intricate details such as corners, pile caps, and expansion joints, where flexibility is essential.
  • Contact Leadax Technical Services for additional project-specific installation guidelines.

Storage & Handling Guidelines

  • Store rolls horizontally in a cool, dry area, away from direct sunlight, extreme temperatures, and moisture.
  • Recommended Storage Temperature: 40-80°F (10-27°C) for at least 24 hours before use.
  • Application Temperature Range:
    • Ambient Temperature: 25°F (-4°C) and rising
    • Substrate Surface Temperature: 25-104°F (-4-40°C)
    • Avoid installation in extreme cold or direct high-heat exposure, as this can affect adhesion performance.

Safety & Limitations

🚫 Do not store rolls in direct sunlight for extended periods.
🚫 Avoid application in inclement weather or on wet substrates.
🚫 Not intended for above-grade waterproofing applications.
🚫 Shelf Life: Approximately 18 months. Always rotate stock for optimal performance.

Torch Safety Guidelines

As Flexowall is installed using propane torch welding, strict safety protocols must be followed:

  • All personnel using torch application techniques must be trained and certified.
  • Only use UL-listed propane torch equipment, including LP gas cylinders, vapor withdrawal valves, pressure gauges, and hoses.
  • Inspect equipment before use for leaks or damage.
  • NEVER use an open flame to check for leaks—use soapy water instead.
  • Follow manufacturer specifications for safe equipment use and torching techniques.

Why Choose Flexowall?

With its advanced SBS-modified bitumen technology, superior adhesion, and seamless waterproofing performance, Flexowall provides long-term protection for critical below-grade structures. Engineered for vertical and foundation applications, Flexowall is a trusted choice for builders, engineers, and contractors seeking efficient, durable, and high-performance waterproofing solutions.

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