The ND WSE-50hd Water Retention Elements have been developed for use in retention roof systems for trafficable surfaces with a roof pitch of 0°. In combination with a flow control device, the water retention element provides temporary and, where required, permanent storage of rainwater. This combination enables a controlled, delayed discharge to the roof drainage system, thereby reducing peak runoff rates.

Integrated coupling system, quick to install

The ND WSE-50hd Water Retention Elements are equipped with an integrated coupling system, allowing all elements to be connected directly to one another easily and securely, preventing displacement during installation and operation.

When used in an inverted roof construction, all specific requirements for retention roofs with inverted insulation (e.g., installation of the waterproofing membrane, connection of the flow control device, etc.) must be strictly observed. The drainage channels arranged on the underside of the retention element support the periodic emptying of the retention layer required in inverted roof systems.

In trafficable areas, the waterproofing membrane must be protected by combining the ND TSF-100 Slip and Protection Sheet with the ND TGF-20 Separation and Slip Film, in order to protect it and decouple it from shear stresses. For detailed system recommendations for inverted roofs, please contact our Technical Sales Team.

How can water storage under traffic-bearing roofs be combined with landscaping?

For trafficable roof systems incorporating vegetated areas, we recommend the use of ND KS Capillary Strips beneath the green roof sections. In this case, the GRK5-classified ND FV-300 Filter Geotextile must be replaced with the special ND KV-200 Capillary Geotextile. To protect the waterproofing membrane, ND SV-500 or ND SV-500M Protection Geotextiles are used beneath the vegetated areas.