Compression-resistant, durable dimpled sheet featuring high drainage and water retention capacities for planted roof constructions.


  • Used as an efficient structural drainage layer in walkable inverted roofs paved with stones or slabs, the innovative DELTA®-FLORAXX dimpled sheet acts as a protection and seepage layer which permits water to drain away freely.
  • Breathable because of the perforation which permits air to circulate, the sheet prevents the formation of a coherent film of water on the waterproofing.
  • Thanks to its robust octagonal dimples additionally reinforced by ribs, its compressive strength is as high as 200kN/m².


  • The sealed surface must be thoroughly cleaned, to avoid damage of the waterproofing after installation of the drainage layer.  
  • For building a green roof, the waterproofing must either be root resistant according to FLL or protected by an additional root barrier. If DELTA®-FLORAXX is installed directly on top of the waterproofing, use an additional protective and separating layer (e.g. 300-500g geotextile) to protect the waterproofing. 
  • The drainage layer is simply rolled out on the underground. With a blade knife the membrane can be cut to the required length. 
  • At the lengths of the membranes an overlapping is not necessary, the membranes are simply laid next to each other (butt joint ) 
  • To extend a sheet, overlap two rows of dimples and connect the sheets with the DELTA®-FLORAXX connector and the rivets, approx.. 5 rivets/2 m. 
  • Install the sheets step by step. 
  • For green roofs an additional geotextile like DELTA®-BIOTOPVLIES must be installed on top of the drainage membrane.

Technical data


Breathable dimpled sheet made of high-density polyethylene

Fire resistance

Normal, class B2 as per DIN 4102

Dimple height

approx. 20 mm

Compressive strength

approx. 200 kN/m²

Drainage capacity

approx. 10 l/s x m

Air gap

approx. 14 l/m²

Operating temperature range

-30 °C to +80 °C

Water storage capacity

approx. 7 l/m²

Vertical water permeability

approx. 1,23 l/m² x s

Chemical properties

Resistant to chemicals and degradation in soil, safe for drinking water

Roll size

2,0 x 20 m

CE conformability

CE-tested as per DIN EN 13252



Your contacts

Do you have questions?



Gründach Delta Floraxxzoom


Dörken GmbH & Co. KG

Dörken GmbH & Co. KG
Wetterstraße 58
D-58313 Herdecke

Phone     0 23 30/63-0
Fax         0 23 30/63-355

Dörken Worldwide

Dörken Worldwide

© Dörken GmbH & Co. KG. · A Dörken Group Company · DELTA® is a registered trademark of Ewald Dörken AG, Herdecke, Germany.