Certified Waterproofing with SOPREMA DuoFlex

SOPREMA’s DuoFlex is a hot-applied, elastomeric waterproofing system designed for use on inverted roofs, roof terraces, protected zero-falls deck, blue roofs, and podiums.

Available in single-pour and double-pour configurations, both systems are fully BBA-certified, confirming compliance with independent performance standards for durability, waterproofing integrity, and weather resistance.

Fully Bonded, Seamless Protection

DuoFlex is applied hot and fully bonds to the substrate, forming a monolithic waterproofing layer that is seamless and void-free. This eliminates the risk of lateral water migration, particularly important in inverted or zero-fall applications where trapped moisture can be difficult to trace or remediate.

The system’s elastomeric formulation accommodates structural movement and thermal expansion, allowing it to adapt to minor imperfections around penetrations or detailing.

System Variants for Project-Specific Needs

• Single-Pour DuoFlex integrates a reinforcement grid and waterproofing protection within a single layer.  This configuration can reduce installation stages, making it suitable for projects with straightforward detailing or time-sensitive sequencing, where permitted by project specifications.
• Double-Pour DuoFlex includes a reinforcing fleece placed over the first pour, followed by a second waterproofing layer applied on top. This layered configuration provides an additional membrane and reinforcement layer, which can contribute to increased protection and service life.

Project warranties are available, up to 30 years for the single-pour system and up to 40 years for the double-pour system, subject to design and installation conditions.

DuoFlex Single-Pour System

Fire Performance and Application Versatility

When installed with approved coverings, DuoFlex systems can achieve a B_ROOF(t4) classification, demonstrating compliance with BS EN 13501-5 for external fire performance. This supports fire safety objectives in accordance with Approved Document B of the Building Regulations.

The DuoFlex system is suitable for a wide range of structural applications including:

• Blue roofs, where consistent waterproofing below water retention zones is essential
• Podium decks and roof gardens, where the system’s tested root resistance and mechanical load capacity are performance priorities
• Zero-fall structures
• Fast-track projects where installation speed and minimal downtime are key

Sustainability and Technical Support

DuoFlex’s demonstrated long service life can help reduce the need for premature membrane replacement, supporting whole-life material efficiency and sustainability objectives. The system is compatible with inverted roof insulation build-ups, enabling designers to meet project-specific thermal performance targets in line with current Building Regulations.

SOPREMA supports DuoFlex with comprehensive technical services, including:

• Wind uplift and drainage calculations
• Bespoke detailing advice
• On-site training and installation inspections
• Guidance to support compliance with building regulations and waterproofing standards

For contractors, the hot-melt application is familiar and efficient, and the system is compatible with a wide range of insulation types and surface finishes, including gravel ballast, paving slabs, green roof build-ups, and blue roof attenuation layers.

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