The Ecological Promise of Living Roofs
Every time it rains, there's a missed opportunity.
Instead of being captured, that water bounces off buildings, rushes over impermeable surfaces, washes into storm drains, and, ultimately, into the earth or out to the ocean. That's a precious resource lost, especially in drought-stricken states.
On the flip side, as storms intensify in a warming world, cities with century-old sewage systems stand to be overwhelmed by flooding.
We may have a solution to both problems, by transforming traditional roofs into living roofs, plants called sedum can absorb stormwater while also providing an outdoor oasis for people.
As cities work to slash emissions and fight climate change, nature-based solutions like living "Green" roofs can increase biodiversity, reduce energy usage, mitigate the "heat island effect," and cut greenhouse gas emissions by insulating buildings and lowering air conditioning demand, are surging in popularity.
Everyone in a hotel, condo office, or apartment – they want to know, how do I get access to air, light, and nature? If you're not paying attention to these statements, you're not going to be competitive as a building owner in the 21st century."
Studies show that it's cheaper and easier to plant a garden on a rooftop than replacing a maze of aging infrastructure and pipelines under city streets.
Green or "living roofs" are not a new concept. In 2017, San Francisco became the first city in the nation to mandate solar and living roofs on most new construction, requiring between 15% and 30% of roof space to incorporate solar, living roofs, or some combination of both. Denver and many others have since followed suit by implementing similar mandates.
At the U.S. General Services Administration's building, wild strawberries grow among native grasses while grapevines creep across the federal building's HVAC units, keeping the system free of dust and reducing temperature fluctuations. The 14,000 square-foot planted rooftop also lowers the ambient temperature allowing the building's solar panels to work more efficiently.
Impact on People
There are multiple psychological benefits to just being around plants; biophilic environments can help calm nerves and increase productivity. There's also something called the restorative effect, where you actually can go back to whatever you're doing and be better at it.
But for most city dwellers, access to green space is not always easy to find, which is why designers and city planners are pushing to create it wherever they can. There's no room in San Francisco, New York, or Chicago to build bigger parks. We can't.