Strategies for climate-friendly roofs

Green roofs or photovoltaics? There currently is a competition of goals for using roof surfaces sustainably: On the one hand, potentials for solar energy should be used as well as possible in order to achieve climate protection goals. On the other hand, cities in particular are increasingly dependent on green roofs to adapt to the consequences of climate change such as heavy rain and heat. The project "Strategies for climate-friendly roof surfaces" is therefore investigating under which conditions a combination or even a separate use makes sense.

To this end, the researchers are evaluating existing scientific findings on behalf of the Federal Institute for Research on Building, Urban Affairs and Spatial Development (BBSR) in order to also shed light on the competing goals from the perspective of different actors, such as homeowners and municipalities. The energetic, ecological and economic advantages and disadvantages of different variants – photovoltaics, green roofs and combined systems) – are to be evaluated.

The multi-stage investigations in the project compile the possible uses of roof surfaces; develop a methodology for the comprehensive evaluation of their effects at the building and district level; and analyze existing obstacles. The resulting recommendations should question the competing goals of photovoltaics and green roofs and contribute to their clarification.