Green Roofs Deliver Critical Protection From ‘Severe Urban Heating’
Sourced from The Energy Mix
As Victoria, British Columbia, commits to removing obstacles to green roof installations and Somerville, Massachusetts mandates their inclusion in new buildings, a Seoul case study underscores the positive social and environmental outcomes of such policy changes.
In January, Victoria councillors unanimously voted to explore ways to help residents install green roofs and rooftop solar, reports Capital Daily, addressing barriers like zoning and floor-space-ratio bylaws.
The B.C. capital’s move comes 15 years after Toronto became the first city in North America to pass a bylaw requiring all new construction with a footprint exceeding 2,000 square metres to incorporate a green roof.
The decision comes just weeks after Somerville, Massachusetts, passed a law that will require all new buildings and major rebuilds with flat roofs to ensure that 80% of roof space is green.
Excluding only “development subject to the city’s Affordable Housing overlay,” the law applies to mid-rise, high-rise, mixed-use, and commercial zoning districts, Pete Ellis, community organizer and manager of the Somerville-based design firm, Recover Green Roofs, told Living Architecture Monitor.
Somerville already has an ordinance that sets minimum requirements for native plants and trees in city-owned parks, public spaces, and streets.
“In a city as dense as Somerville, it is a real challenge to find ways to create meaningful new green space,” said Coun. Ben Ewen-Campen. “Green roofs are a great tool to help us solve this problem—and people love them.”
And while the beautifying and biodiversity-boosting reasons for green roofs are obvious, new research from Seoul’s Kyung Hee University and the University of New South Wales shows they also come with clear public health and climate benefits.
Running “large-scale cooling climatic and building energy simulations under three greenery coverage scenarios to evaluate the potential of green roofs to lower the temperature and cooling needs of Seoul during the hottest summer month, August,” the team found that green-roofing 90% of its buildings decreased the city’s air and surface temperatures by up to 0.54 and 2.17 °C, respectively, reports Mirage News. That cooling translated into a 7.7% drop in building energy demand for air conditioning.
The heat stress-easing changes were generated by “non-irrigated extensive green roofs—a type of lightweight green roof with large-scale implementation potential and lower maintenance costs.”
From the Living Architecture Monitor
