Water storage membrane DELTA®-FLORAXX TOP

Diffusion-open protective and drainage membrane with water storage function and equipped with an integrated, filter-stable geotextile. Surface drainage and water storage in one. Ideally suited for use on green as well as on inverted roofs.

The dimpled membrane is safe for drinking water, resistant to chemicals and does not rot in the ground.

    smallRetina 11:21:19
    DELTA®-FLORAXX TOP in der Anwendung
    smallRetina 11:21:19
    DELTA®-FLORAXX TOP in der Anwendung
    smallRetina 11:21:19
    DELTA®-FLORAXX TOP in der Anwendung
    smallRetina 11:21:19
    DELTA®-FLORAXX TOP water storage membrane
    smallRetina 11:21:19
    DELTA®-FLORAXX TOP Oktagonnoppe
    smallRetina 11:21:19
    DELTA®-FLORAXX TOP Anwendung unter Intensivbegrünung


  • Large water reservoir of approximately 7 l/sqm
    DELTA®-FLORAXX TOP stores rainwater. This is why it serves as a water reservoir for dry periods. Excess rainwater runs off through the perforation holes punched in the dimpled sheet and can be drained on the roof waterproofing between the knobs.
  • 80% higher compressive strength
    Thanks to the octagon knob with reinforcing ribs, it has an approx. 80% higher compressive strength than standard nubs.
  • Integrated filter fleece
    The laminated, filter-stable geotextile permits the application of the plant substrate immediately after the drainage and after the application of the water storage layer. No further filter layer must be applied. This saves additional effort.
  • No silting up
    The laminated geotextile is pressure and filter stable. This way it can reliably prevents the dimpled sheet from becoming silted up.
  • Perforation holes between the dimples
    The perforation holes guarantee that excess rainwater (approximately 8.7 l/m²s) is drained away, thus avoiding root rot, for example.
  • Vapour-permeable
    Thanks to the perforation holes, the product DELTA®-FLORAXX TOP can achieve an SD value of approximately 0.4 m. So, it is ideal for the use on inverted roofs.


DELTA®-FLORAXX TOP serves as a protective, drainage and water storage layer in extensive as well as intensively greened flat roof constructions. The dimpled sheet is rolled out on a protective fleece (min. 300g/sqm) above the root-proof seal with the dimpled side down. Since the filter-stable geotextile has already been integrated, the plant substrate can be applied directly to the product DELTA®-FLORAXX TOP during the next step. The planting is then done individually.

DELTA®-FLORAXX TOP is also used in the inverted roof as a diffusion-open cover for the thermal insulation. The dimpled sheet is laid on a water-draining separating layer with the knobs facing the roof insulation. After that, the required fill (plant substrate, chippings, gravel, crushed stone, etc.) will be applied directly to the DELTA®-FLORAXX TOP. Even in the inverted roof, greening, the creation of terrace areas or simple gravel is possible without any problems.


Technical data

Material of the dimpled sheet Dimple membrane perforated with laminated PP geotextile
Dimple height approx. 20 mm
Compressive strength approx. 200 kN/m² (EN ISO 25619-2)
Air gap approx. 14 l/m²
Servicetemperature range from -30 °C to + 80 °C
Water flow capacity in the plane approx. 10 x 10-3 m²/s (10 l/s · m) (EN ISO 12958)
Water permeability with vertical inflow ca. 8,5 l/m² · s
Perforation diameter ca. 6,5 mm
Water storage capacity ca. 7 l/m²
Characteristic opening size geotextile ca. 0,15 mm (EN ISO 12956)
Water permeability geotextil ca. 0,08 m/s (EN ISO 11058)
Water drainage capacity 1,17 l/m · s at 20 kPA (Gradient i=0,02)
1,43 l/m · s at 20 kPA (Gradient i=0,03)
2,64 l/m · s at 20 kPA (Gradient i=0,1)
CE conformity DIN EN 13252, test report TBU1.1/13525/0580.0.1-2009
Roll size 10 m x 2 m, fleece width 2,10 m




smallRetina 11:21:19 mediumAlias 11:21:19 large 11:21:19 xlarge 11:21:19

Would you like information on detailed product properties, use cases or other technical topics?
Then feel free to contact our application department on +49 2330 63 578 or atabvf@doerken.de.

Do you have questions about prices, availability or the status of your order?
Our sales service will help you with these matters on +49 2330 63 636 or membranes@doerken.de.