Building green roofs in cities is already a necessity

Stefano Boeri Architetti: Bosco Verticale, Milan (2009-14)

Prague – Building more green roofs in Czech cities, which reduce temperatures and retain rainwater in the summer, is becoming a necessity. Architects agreed on this at today's discussion "Green Islands in the City" held in Prague's Lucerna. In Prague, the care for tree lines in the streets should be improved by a new expert working group currently being prepared by the Institute of Planning and Development of the capital city of Prague (IPR), said Jan Richtr, head of the IPR office, at the debate.

The new team of experts, including urban planners and landscape architects, should prepare a methodology to improve the establishment and maintenance of street tree lines. "This is a pressing problem. There are many managers in Prague, and their work is not coordinated. The working group will also address new technologies to ensure that trees can thrive in the city's streets," Richtr stated.

To implement procedures that help improve the urban microclimate, the city hall is willing to "reach into" Prague's building regulations, said Prague Mayor Zdeněk Hřib (Pirates). However, he did not specify how exactly.

According to architects, the perception of green roofs, which help address the impacts of climate change in overheating cities, is still seen as exotic. They are often not favored by heritage protectors or officials for various reasons, and due to poor information, often by the general public as well.

"This year has definitively shown that green roofs, which we architects have been advocating for decades, are not some trendy nonsense but are indeed a matter of survival. The heat islands created by cities can destroy the culture that lives within them," said Jan Kasl, chairman of the Czech Chamber of Architects, to ČTK. Like green roofs, he believes that natural green facades would also benefit cities, providing a softening aesthetic element, absorbing pollutants, carbon dioxide, and capturing airborne particles.

Regarding green roofs, experts highlighted the fact that they are a relatively inexpensive way to reduce city temperatures by up to ten degrees. Additionally, they attract visitors and potential investors. However, they did not agree on whether their construction should be mandatory. Kasl would be in favor of introducing a requirement for large investors and the commercial sector. Rules should primarily be determined at the municipal level, he added. According to him, there could be grant support from the city for the public. Experts believe that building green roofs makes sense not only in large cities but also in villages.