Multifunctional roofs: the new horizon of Rotterdam

Multifunctionality as the new standard

Green roofs have already made their mark, with their positive impact on urban climate and well-being. But what makes a roof multifunctional and why is this so essential? Paul van Roosmalen, Program Manager of Multifunctional Roofs for the Municipality of Rotterdam, sees the city as a hotbed of ideas and experiments. He emphasises that traditional solutions are no longer adequate for today’s urban challenges. “Multifunctional roofs go beyond the role of mere protection against the elements. They offer a wide range of functions, from green spaces to energy generation, water retention, and social meeting places. This presents a unique opportunity to optimise urban space while simultaneously contributing to the resilience and sustainability of the city. If we are serious about creating space for all urban challenges, from climate change to densification and mobility, we need to see our roofs as multifunctional hubs where various solutions converge.

"Multifunctional roofs go beyond the role of mere protection against the elements. They offer a wide range of functions, from green spaces to energy generation, water retention, and social meeting places.”

- Paul van Roosmalen, Program Manager of Multifunctional Roofs, Municipality of Rotterdam

Remarkable transformations

The Dakpark Rotterdam, high above what seems like an ordinary parking garage in Rotterdam-West, stands as an impressive example of this urban metamorphosis. This green wonderland, one of Europe’s largest rooftop gardens, offers not only stunning views of the city but also a haven of peace and nature above the hustle and bustle. With green spaces, walking paths, and playgrounds, the Dakpark serves as a vibrant symbol of Rotterdam’s commitment to greener and healthier urban environments.

But the Dakpark is just the beginning of a broader movement redefining Rotterdam. Atop the Schieblock building, in the bustling heart of the city, the DakAkker project flourishes as a beacon of sustainability and community spirit. Here, an organic urban farm thrives amidst the concrete jungle, growing vegetables, fruits, and herbs. This project serves not only as a source of fresh produce but also as an educational space where residents can learn about sustainable farming practices and food production.

Another notable example: in 2022, the monumental concert and congress building De Doelen was adorned with a green/blue roof, spanning an area equivalent to ten tennis courts of vegetation and water storage. Beneath the vegetation, a system of crates has been installed to capture about two thousand bathtubs worth of rainwater.

Rotterdam, however, continues to look ahead. Plans for a park atop the city’s longest building are already in place. This park, named Hofbogenpark, will transform the former railway line into a lush, green oasis stretching two kilometres. Designed with climate adaptation in mind, the park will welcome native plants, flowers, bees, and playing children. As one of the seven urban projects Rotterdam is implementing, Hofbogenpark promises to contribute to a greener and more sustainable living environment for all Rotterdammers.

Additionally, many other roofs in the city – office buildings, apartment complexes, homes – are equipped with solar panels and sometimes even wind turbines to generate sustainable energy. In short, we are making great progress!

Challenges

Behind the striking metamorphosis of Rotterdam’s roofs lies a powerful drive: the urgent need to build cities resilient to the challenges of the future, particularly climate change. However, multifunctional roofs offer not only practical benefits, such as rainwater retention and improved air quality but also create space for social interaction and community building. They also embody a smart solution to the pressing space constraints in our cities. Rotterdam maximises the use of valuable urban space by integrating diverse functions on one roof. This integration not only enhances efficiency but also creates synergy that significantly enhances the resilience and sustainability of the city. Of course, these innovative roofs come with challenges. The weight of the roof, safety regulations, and the transition to multifunctional use present challenges that we in Rotterdam will never shy away from!