KBF roof stores 9,828 gallons of rainwater

This Retention Roof significantly reduces pressure on the urban sewer system. It stores 9,831 gallons of rainwater, far exceeding Amsterdam’s regulations, and drains slowly with a controlled capacity of $1text{ gallon/ft}^2$ per hour, even on a flat roof.

Multifunctional Surface

Every component of the roof plays a role. Rainwater is buffered, and nature is afforded space to flourish.

Climate adaptive design

The roof stores water during heavy rainfall and helps cool the surroundings during summer heat.

Biodiversity in the Built Environment

A diverse planting plan attracts pollinators, birds, and native insects. This turns the roof into a thriving ecosystem.

Sustainable Transformation of an Urban Icon

The former production hall in Amsterdam’s iconic Gum Ball Quarter has undergone a spectacular transformation and is now reopening its doors as the KBF Warehouse: a vibrant work and meeting place for creative entrepreneurs. Under the visionary leadership of NEXT Architects, the building has been transformed into a model of sustainable innovation and urban redevelopment. The beating heart of this renovation is the 6,670 ft² multifunctional roof, which combines sustainability and functionality. This so-called Retention Roof integrates green (vegetation), blue (water), and yellow (energy) and is a powerful and effective solution for extreme weather conditions.

Smart water management: turning rain into a resource

The Retention Roof captures and temporarily stores 9,831 gallons of rainwater, exceeding Amsterdam’s Rainwater Ordinance requirement of 16 gallons per square yard. With a controlled discharge of 0.26 gallons per square yard per hour, the roof relieves pressure on the sewer network while promoting evaporation and infiltration. Even without slope, the system drains effectively thanks to precise engineering and collaboration between project partners.

Multifunctional and Climate-Proof

The roof not only meets water storage requirements, but also offers numerous other advantages in addition to water management. It reduces heat stress, preserves biodiversity, generates energy, and serves as a usable space for employees. Sempergreen supplied Sedum mix mats which, together with the Optigrün WRB 85i Retention Roof System, form the basis of this green-blue solution. In addition, PV panels have been installed by partners for sustainable energy generation. The result is a multifunctional roof that combines aesthetics, sustainability, and utility value.

Unique Features of the Retention Roof

By combining Sempergreen Sedum Mix Blankets with the Retention system and solar panels, this Bluegreen Roof contributes to:

Reducing Heat Stress:
The greenery keeps the environment cool and improves the microclimate.
Preserving Biodiversity:
The green roof provides a habitat for flora and fauna.
Energy Generation:
Integrated solar panels make an important contribution to sustainable energy supply.
Functionality:
The roof is accessible to employees and provides a green, inspiring environment.

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