Building with water

Restoring the water cycle in the built environment

We tend to forget about water in our built environment, and infrastructure to catch rainwater is still in its infancy. Instead, all our building codes are focussed on drainage, explains Friso Klapwijk, Global Director Urban Climate Resilience at Wavin. Over the past ten years, Friso has developed a roofing system that helps to harvest rainwater and consider water as a valuable resource from the first drop of rain to the final runoff – with hydrological, thermal, and environmental benefits.

Last updated: July 30, 2023 Rotterdam, Netherlands

By Friso Klapwijk, Global Director Urban Climate Resilience, Wavin

Watch this 10-minute video and reply to the poll below – Friso would like to hear your thoughts and questions.

Hydrological advantages of circular water management

Friso Klapwijk has developed a system that transforms flat roofs on existing or new buildings into reservoirs that retain rainwater in a thin attenuation layer, and then manages the further use of this water using an integrated irrigation function.

By retaining rainwater on site, the system reduces the volume of water discharged into the sewer during downpours and the possibility of sewer overflows, as well as reducing water demand that may contribute to groundwater depletion.

Further advantages in thermal and environmental performance

The system also reduces the temperature of the roof, lowers heat gain within the building, extends the life expectancy of the roofing material, and reduces the building’s contribution to urban heat entrapment. Further, the roofing system provides a dense layer of localized climate data that can better inform urban flood management.

In terms of environmental performance, the PolderRoof® automatically irrigates large planters on each level of the building, allowing plants to thrive without the need for residents to actively monitor water levels. Expanding the areas of green space within the urban environment improves biodiversity, urban climate resilience, and building efficiency.

Holcim Foundation Sounding Board

The Holcim Foundation Sounding Board enables built environment innovators to explore their ideas that challenge conventional building practices with industry-leading peers.

Wavin shapes the future by creating pioneering water and pipe solutions and is committed to sustainability, driving innovation to ensure clean water, efficient energy use, and resilient infrastructures.

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