DNB roof gardens form ecological whole with surrounding park

The headquarters of De Nederlandsche Bank on Frederiksplein in Amsterdam is undergoing a major renovation. In the process, several roof gardens are being created. "Everywhere it was possible, bitumen has been replaced by green roofs," says Pieter Hoen of Mecanoo. This will make the building part of the green environment. "We want to use our site to make a positive impact on the city of Amsterdam," said Maaike van Leuken of DNB.

Maaike van Leuken, divisional director of operations at De Nederlandsche Bank, says: "Having moved the gold and money to Zeist gives us the opportunity to make different decisions with our headquarters in Amsterdam and get closer to our identity. DNB's mission is financial stability and sustainable prosperity for now and the future. Maintaining a healthy society is linked to climate transition and biodiversity. Together with Mecanoo, we want to make visible what we stand for. In doing so, we want to connect with the urban environment in which we are housed: the Stadhouderskade is the most polluted street in Amsterdam, with a lot of heat stress and fine dust emissions, a mer à boire to work with. DNB and Mecanoo found each other in how we can use our site to make a positive impact on climate, work happiness and the people in the city."

Pieter Hoen is director of urbanism and public space design at Mecanoo. He explains, "DNB stands on what is now called Frederiksplein; a good name, because it is primarily a traffic square. It was immediately clear to us that that had to become a park. With the City of Amsterdam, the transformation from square to park is now underway. The park will form an ecological whole with the spaces of DNB. In practice, that means choosing plants and trees in such a way that you help the birds and insects that live in the park."

A key intervention is that one of the DNB's two towers has been demolished for reuse elsewhere. This round tower was added to Duintjer's design more than 25 years ago and, because of its construction, can be given a fully circular repurposing. Hoen: "Where the tower stood, substantial space has been created for a beautiful garden. This rests on the underground parking garage. The construction is strong enough for trees. This will be the publicly accessible City Garden, with a forest-like atmosphere. Here and elsewhere there will be works of art: the connection between art, greenery and recreation offers beautiful opportunities. When you enter the building, you can immediately see through the building the greenery of the City Garden." 

But the City Garden is emphatically not the only area where greenery has been added. Hoen: "Wherever it was possible, bitumen has been replaced by green roofs. At minimal build-up sedum, but where possible an intensive roof garden. So when you work here, you look out on greenery everywhere." Van Leuken emphasizes, "We see our office as much more than a collection of desks: DNB's work environment is a place where employees can experience nature as a natural part of their working day. Green gives space in your head, energy, creativity." One level above the City Garden is the Inner Garden. Hoen: "We created an orthogonal design for the greenery there. More than 70 square meters are available for edible plantings, the harvest of which can be utilized in the restaurant. The Inner Garden offers alcoves, space for a walk and a nice view from the tower." Another level higher, on the roof of the third floor, will be the Walking Garden. Hoen: "There you feel you are in a park. You're looking up against the treetops. That's why we didn't put trees in the Walking Garden, but rather plants that provide food for the birds in the treetops of the park." The highest garden is Het Baken. "From here you can see all of Amsterdam. You feel the space and the openness. We therefore chose grasses as plantings. So for each space we looked at what suits this place and what the highest achievable biodiversity is. Each garden has its own character and its own planting, but there is consistency in materialization and because we created a family of planters." The various spaces in and around the building each complement Frederick Park in their own way. The 120-meter-long quay next to the building will be publicly accessible and wheelchair-accessible, with a bamboo composite deck. Hoen: "Quays in Amsterdam are always three meters above ground level, but we have lowered this quay so that people can paddle in the Singelgracht."

"Mecanoo was able to work with us to translate what DNB stands for," says Van Leuken. " From our fields of expertise, we inspired each other to more and more possibilities. The chemistry between Mecanoo and DNB was fantastic. What we want to pass along to everyone: when choosing an architect, don't forget how important expertise of the outdoor space is. That at Mecanoo architecture and landscaping are fully integrated led to this wonderful design in our case."