A lightweight and consistent drainage layer featuring a geotextile filter that collects and stores water to irrigate plants during low rainfall periods. The core acts as a water reservoir for plant roots to access in dry intervals.


gtRoofdrain is designed for use in extensive green roof systems to provide both drainage and attenuation in a convenient, lightweight and cost effective system.

The drainage design of intensive green roofs requires only a simple soil layer; by contrast the modern method of an extensive green roof requires a combination of efficient drainage and water attenuation in order to allow the ecology to flourish.

gtRoofdrain allows the storage of water within the nodes of the of the HDPE core, whilst facilitating the efficient drainage of any excess water away from the roof. This helps prevent the root growing media from drying out during dry periods and from becoming waterlogged during periods of wet weather.

When used within a roof construction, gtRoofdrain provides a versatile system for the collection of surplus seepage water at the base of the growing medium and for the prevention of water pressure build up on the structural waterproofing.

gtRoofdrain Applications

  • Green roof drainage
  • Green Bridges and Green Tunnels
  • Extensive green roofs
  • Brown roofs and biodiverse roof drainage
  • Water attenuation
  • SuDs Systems

gtRoofdrain Benefits

  • Prevents plants from drying out
  • Prevents waterlogging
  • Provides drainage
  • Assists in roof cooling
  • Lightweight
  • Easy to install

Downloads & Datasheets