Rethinking Rooftops

Abstract

Rotterdam’s almost untapped roofscape offers an exceptional chance to solve large urban, and environmental problems cities are facing nowadays. Take for instance, climate change, energy transition, loss of biodiversity, and the shortage of public places. Therefore we should rethink flat roofs, and expose their potential. In many different ways, they could contribute to the development of a sustainable and resilient city in the future. Especially, multifunctional, green roofs are able to reduce heat stress, store (temporarily) water, purify the air, enrich biodiversity, and accommodate social functions, especially when there is a possibility to connect all those ‘hidden’, unused spaces in the city. There are already a lot of initiatives in Rotterdam, that come up with all different ideas to fill in the 18 square kilometers of flat roofs we have at our disposal. However, this is mostly about the (re)development of a single plot, a building block, or a street. If we really want to tackle those large urban challenges, we should not only see the potential of a single roof but zoom out and see how at a city scale the roofs could be transformed into a liveable roofscape.

This thesis explores the potential and redevelopment of flat roofs in the city center of Rotterdam and aims for a whole new flat rooftop network above the existing city. The main research question is: How can the (re)development of Rotterdam’s flat roofs be guided to achieve significant progress towards a sustainable and resilient Rotterdam? By analysing the existing urban fabric, investigating possible functions flat roofs could accommodate in relation to large urban scale problems, and seeing the technical implications and possible limitations, a proposal for a rooftop toolkit and strategy for the city of Rotterdam is formulated. The main research method is research by design. This all to support the growth of Rotterdam in the upcoming years and make the city even more sustainable, resilient and liveable in the future.