Pesälä couple showcases unique lichen-covered roof in Oulu, Finland

A carport owned by Roosa and Karri Pesälä in Oulu has captured the attention of passersby with its unique lichen-covered roof. This aesthetic choice was no accident; the Pesäläs intentionally constructed a green roof for their carport next to their log house over the summer. “We chose lichen because we wanted a beautiful, native, and harmonious solution with the log structure,” Roosa Pesälä explained. “Lichen is also low-maintenance, requiring only annual weeding of tree roots and weeds.”

Next summer, Oulu’s housing fair will showcase more green roofs, as the city’s building regulations mandate their installation on utility buildings and carports in the Lehtokylä residential area. In addition to lichen, the roofs of the exhibition buildings will feature other plants such as sedum and meadow flowers. Environmental biologist and landscape designer Taina Suonio, recognized internationally for her work in green roofing, celebrates Oulu’s initiative and notes that the adoption of green roofs is gradually increasing throughout Finland.

Suonio emphasizes the numerous benefits of green roofs, particularly in urban areas amidst rising temperatures. “Vegetation helps manage stormwater by reducing runoff and utilizing rainwater,” she said. Furthermore, green roofs mitigate urban heat islands, which can exacerbate heat-related mortality, particularly among senior citizens.

Suonio encourages introducing native meadow flora to rooftops to support pollinators and enhance biodiversity in cities. She also advocated for the incorporation of plants on building facades, urging a move away from traditional views that discourage greenery on walls. Proper planning, she assures, can prevent moisture-related issues, provided collaboration with professionals is maintained. Green roofs are not only sustainable and aesthetically pleasing, but they also extend the lifespan of roofing structures, often lasting two to three times longer than conventional materials.