RIW Double Drain

RIW Double Drain is a cold-applied HDPE profiled drainage sheet bonded with a permeable geotextile filter fabric, engineered to manage groundwater at the external face of a structure. Rather than acting as a barrier membrane, it works by channelling groundwater away from the structure to land drainage, effectively relieving hydrostatic pressure and preventing water buildup against the waterproofed surface.

The geotextile filter fabric prevents fine soil particles from entering and blocking the drainage layer, ensuring long-term drainage performance even in challenging ground conditions. The product's good impact resistance also makes it an effective protection layer for primary waterproofing systems during backfilling and construction activity, guarding against mechanical damage that could otherwise compromise the membrane.

Benefits

• Double drain can be used on its own to isolate the structure from surrounding earth or in conjunction with a primary waterproofing system
• Relieves hydrostatic water pressure
• High drainage capacity
• Good impact resistance, providing protection to the primary membrane
• Quick & easy to install
• Prevents ground water reaching structure

Good to know

• Eliminates necessity for granular backfill
• Can be applied to concrete masonry and a primary membrane.
• J40 - Flexible Sheet tanking/Damp Proofing in accordance with NBS Clauses
• Surfaces should be clean and dry before application
• Double Drain should be applied to the outer face of the structure, with the geotextile filter fabric facing outwards