Drainage drainage board DRAINMAT P20

water storagegreen roof drainageshear force protection

Overview
Urbanscape Drainmat P20 is a 20 mm drainage and reservoir membrane manufactured from high-density polyethylene (HDPE) specifically engineered for flat green roof systems. The product is perforated on one side so it can be installed with the holes facing upward to retain water. The membrane is permeable and is also suitable for inverted roof assemblies. Its compressive strength is approximately 150 kN/m² (≈ 15 tonnes per m²), providing structural bearing capacity for planted and service areas. In walkable areas without vegetation the geotextile can be omitted; the base layer and bedding material can be applied directly on the dimpled membrane.

Applications

• Flat green roof systems
• Inverted roof assemblies
• Walkable roof areas without vegetation (direct bedding on membrane)
• Roof areas requiring combined drainage and local water retention

Benefits

• Integrated drainage and water storage for plant support
• Lightweight solution for reduced structural load
• Efficient installation with one-sided perforation
• Compatibility with inverted roof build-ups
• Contributes to thermal and acoustic performance of the roof assembly
• Designed compressive capacity (≈ 150 kN/m²) for planted and service zones
• Fire performance suitable for roof applications

Characteristics / Technical specifications

• Height: 20 mm
• Material: High-density polyethylene (HDPE)
• Perforation: Perforated on one side; install with holes facing upward for water retention
• Application: Designed for flat green roof systems; suitable for inverted roofs
• Pressure resistance: Approx. 150 kN/m² (≈ 15 tonnes per m² compressive strength)
• Permeability: Permeable water-storing drainage membrane
• Walkable areas: In walkable areas without vegetation, no geotextile is required; base layer and bedding material can be applied directly on the dimpled membrane