Drainage and filtration layer
The drainage and filtration layer is designed to drain excess water quickly and effectively. The green roof drainage layer is required on roofs up to a 5° slope; drainage is not used on roofs with a higher slope. For drainage, loop mats, bucket mats or gravel of the appropriate fraction are used. A geotextile, i.e. a filter, is placed on the drainage, which is designed to prevent the substrate from clogging the drainage.
Polypropylene or polyester geotextile, used as a filter under the substrate or a protective layer, separating the roof waterproofing and the green roof system.
Used on flat roofs as drainage with a minimum thickness of 5 cm and for backfilling around the roof, chimneys, fans, etc. It can be used as a ballast layer in an inverted roof system.