MVRDV, Superworld, and the City of Rotterdam Create Software for Reimagining Rooftops

Revealed today at the Smart City Expo World Congress in Barcelona, ​​RoofScape is an attempt to answer this call. Developed by MVRDV’s tech task force MVRDV NEXT, alongside Superworld and the Municipality of Rotterdam, the RoofScape prototype is a visualization engine for Rotterdam’s rooftops. It proposes an accessible means of incorporating the growing ecosystem of municipal urban data, producing concrete suggestions that simulate the interplay of rooftop programs (green, water retention, residential, and social spaces) according to an impact matrix defined by the city to stimulate the activation of this relatively underutilized urban layer.

RoofScape has been developed in response to a particular area of ​​focus for the Municipality of Rotterdam: the city’s rooftops. It builds on a prior collaboration between MVRDV and the Municipality – together with the foundation Rotterdam Rooftop Days, in 2021 they launched the Rooftop Catalog, a book containing 130 suggestions for how rooftops can be used more effectively to increase the city’s density and do everything from providing more housing and leisure spaces to support biodiversity and generating energy. Included in this publication was the revelation that Rotterdam has over 18 square kilometers of flat roofs that is almost entirely wasted space – a large area for potential growth that has become one of the city’s urban planning priorities.

“The Rooftop Catalog was a huge success in raising people’s awareness of what we see as a resource for the city, and generating some excitement over what could be done with it,” says Paul van Roosmalen, the program manager for the city’s Rotterdam Rooftops program . “The next steps though are complex. How can you possibly write city policy without a clear overview of the possibilities in different areas? And how can you get an overview of the 18 square kilometers of space when it comprises thousands of smaller areas, each with unique conditions and requirements?”

RoofScape is thus intended to be detailed and informative enough to assist policy makers and urban planners, while also being so simple to use that individual building owners – and even just interested citizens – can ‘play around to see what kinds of uses might emerge on their buildings’ and in their neighborhood. It relates the Rooftop Catalog to urban zoning laws and public policy offering a feasibility counterpoint to the catalog’s inspiration; together, the creators hope the two tools will help in a proliferation of well-considered, location-specific additions to the city’s roofscape.

“It’s funny that when you look at what people want from their cities, everyone loves a rooftop terrace, for example. Almost everyone sees the need for more housing, and I think most people would prefer to look out of the window onto a nice green meadow than a gray flat roof. And yet most cities aren’t really looking at their empty rooftops as an opportunity,” says Superworld co-founder Maxime Cunin. “I think that’s because planners and policy makers are looking for big changes they can make with one sweeping decision, not a thousand small decisions. RoofScape closes that gap a little.”

“In our opinion, it was crucial that the software integrates expert knowledge while remaining easy enough for all people to use,” adds Leo Stuckardt of MVRDV NEXT. “Rotterdam’s rooftop mission is an unusual urban design ideal – it can’t be done with one big decision, or even with one organization balancing the wishes of a thousand people. You have to kind of set some basic rules, provide people with the right information and incentives, and see what emerges. RoofScape addresses the diversity of ownership, dreams, and ambitions that need to be negotiated and explores how municipalities can steer these developments through public policy.”

Rotterdam’s existing rooftop standards inform the simulations the software provides. These standards color-code roofs by what uses they can support: while some might support relatively heavy additional structures such as homes or offices (coded purple), others may only be capable of supporting energy-generating infrastructure such as photovoltaic panels or windmills (yellow ). Other roofs might be better suited for greenery and other biodiversity (green), Collecting and storing rainwater (blue), hosting a building’s technical equipment (grey), adding new social spaces (red), or improving the city’s transport and mobility (orange) .

For each roof, the software scores its suitability for each of these seven colors. To make these judgments, the tool combines a wide range of datasets: using the city’s digital twin, it analyzes each building’s height, roof area, compactness, and roof slope (as well as a whole host of additional parameters), and combines this data with municipal information such as building function, age, energy label, energy production potential, view quality, and heritage status. Finally, it considers area-based datasets such as access to public space and transit, recognized green corridors, heritage-protected city zones, flood risk, and urban heat island effect.

For example, a building’s age typically plays a big role in assessing its suitability as a “purple” roof. Very old buildings have unreliable structures, and very new buildings are usually highly optimized for nothing more than their designed use, so the sweet spot for a building that can support heavy additional floors is typically between 50 to 100 years old. Similarly, a steeply sloped roof might be deemed inappropriate as a “red” roof with social space, but might be angled perfectly to support solar panels, netting it a “yellow” label.

By zooming in on a specific neighborhood and setting a few threshold sliders to their liking, users can see what kind of roofscape might emerge in that area. Focusing on a specific building allows them to look deeper into the factors that come from their assigned color label.

Though it is currently still a prototype, the team already has plans for RoofScape’s future development. “This first prototype is a call to action. We’re hoping to get more cities and other stakeholders involved in the next steps for RoofScape” says Van Roosmalen. “This would enable us to scale the tool up towards a common rooftop standard that is directly implemented in digital twins and planning tools.”

“We still need to add more layers to it – literally,” adds Stuckardt. “If you look at the Rooftop Catalog, there are lots of ideas that actually combine functions. Maybe a biodiverse green roof can be great at capturing and storing water, for example, or an added structure like an office incorporates some social space as well. Layering is a critical concept, and most roofs should be able to do more than one thing. If RoofScape can suggest multiple suitable functions for each roof, it starts to imply more specific designs that people can investigate.”

Project credits

• Location: Rotterdam, The Netherlands
• Client: Gemeente Rotterdam, Rotterdam, The Netherlands
• Site area: 319 km2
• Program and size: Various urban programs
• Team: Winy Maas, Jacob van Rijs, Nathalie de Vries, Sanne van der Burgh, Leo Stuckardt, Jaka Korla
• Partners/ Co-architect: Superworld (Rotterdam, The Netherlands)
• Video: Kirill Emelianov