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Retention Roof Flow Control Intensive

A green roof for the sponge city

The connection between intensive green roofs and the sponge city concept is actually quite simple: a green roof creates many small storage spaces for water. Precipitation is retained and stays where it falls. Intensive green roofs also delay evaporation. The sponge city therefore absorbs water and releases it again with a delay. This improves the urban climate.

How can the principle of the sponge city be implemented in practice? This is where our RETENTION ROOF FLOW CONTROL INTENSIVE is recommended. It is suitable for intensive green roofs where there are special structural requirements with regard to flooding volume and runoff retardation.

The water retention box (WRB) is used as a water storage and drainage element. Depending on the requirements, the WRB element can be used as a permanent water reservoir and/or as a temporary retention area to delay runoff.

The water retention box for intensive green roofs is a particularly efficient system with a very high storage capacity. The WRB 85 elements are highly pressure-resistant and are connected to each other in such a way that a flat, closed surface is created. This enables the construction of intensively used roof areas with sections that can be walked and driven on.

The RETENTION ROOF FLOW CONTROL INTENSIVE is an intervention mitigation measure within the framework of the intervention compensation regulation and fulfills the requirements of the FLL Green Roof Guidelines.

Ecological value
Maintenance costs
Costs*from 77 €/m2

* Standard cost value for 1,000 m², net incl. installation, material varies from region to region.

System structure retention roof flow control intensive

Note: Click on the marked points to get more information!

Intensive Roof Greening

Intensive Substrate I (230-400 mm)

  • Alternative: Lawn substrate R (min. 20cm)
  • A substrate with high water storage capacity and good air porosity, tailored to intensive multi layer systems.
  • learn more: Intensive substrate i
  • learn more: Lawn substrate R

Filter and Capillary Fleece FIL 200K

Water Retention Box WRB 85

  • Water Retention Box made of recycled PP material
  • With high temporary and possibly permanent retention volume in combination with a Flow Control System for specific regulation of water discharge and/or water storage.
  • learn more: Water retention box WRB 85

Capillary Bridges

Capillary Bridges to transport stored rainwater from the drainage level into the substrate layer and to increase evaporation (accessories)

Protection and Storage Fleece RMS 900

Technical specifications

Weight*from 320 kg/m² or 3.2 kN/m²
Build-up depthfrom 330 mm
Roof pitch0°
Vegetation formPerennials-shrubs-lawn areas
Discharge coefficientProject specific settings possible
Retention volumeapprox. 80 l/m² (WRB 85)
Water storage***from 170 l/m²

Optigrün Retention roofs win the PLUS X AWARD

Optigrün international AG is the proud winner of the PLUS X AWARD, the world's largest innovation award for technology, sports, and lifestyle. It honors brands for the quality and innovative edge of their products. The award is presented by an independent, international jury of experts.

Optigrün retention roofs impressed in 5 out of 7 categories and were awarded seals of approval for Innovation, High Quality, Ease of Use, Functionality and Ecology. These serve as a guide for customers and retailers when making purchases, stand for outstanding product features, and help to quickly and clearly recognize the added value of an award-winning product over the competition.