Green Roofs: Enviro and Mental Benefits
By Angela Loder
The numerous environmental benefits associated with green roofs are undeniable. Especially considering the City of Toronto planted their own green roof atop City Hall that promises to shrink the building’s energy consumption by 10 per cent. Likewise, Toronto has passed some of the most stringent green roof legislation in North America.
However, recent research has shown that green roofs may provide health and well-being benefits to those who look out on them. In a study, researchers found a majority of office workers in Toronto and Chicago who overlook green roofs from their workplace felt the sight of greenery amid concrete and glass gave them a mental break from the workday. This mental breathing space was described as calming and peaceful, and helped office workers gain perspective and clarity about the problems facing them during the day. This was particularly true if the green roof was accessible and provided a space for participants to take a break from their desks.
Green roofs also gave many office workers a sense of hope about our ability to address environmental problems and pride about the organization responsible for the green roof – both of which influence well-being.
The scale and aesthetics of green roofs were found to influence the perception of their associated health benefits, some examples are shown below:
Chicago City Hall Green Roof:
Chicago’s award-winning green roof mimics the long-lost prairie native to Chicago and hosts birds, butterflies, and bees. Many participants found the roof beautiful, though colour and detail was lost if viewers were too far away. The “messy” aesthetic of prairie-style vegetation will be popular with environmentalists, but might need explaining to your lawn-loving neighbours.
This sedum green roof on a parking garage in downtown Chicago met the minimum requirement of 50 per cent coverage, but participants found it looked half-finished and was aesthetically unappealing. If choosing a light-weight sedum green roof, try to add colour and variation for more aesthetic appeal.
One of the first green roofs in Toronto, MEC’s prairie-style vegetation was also sometimes described as “messy,” but participants appreciated its ecological benefits and seasonal variation. The small wildflowers do not tend to be visible from a distance, so you might want to experiment with some border colour or patterns if it will be seen from afar.
Employees can take a break from their desks to have lunch on one of two accessible green roofs that overlook the skyline. Because employees were on the roof, colours and flowers were more visible and employees loved the seasonal variations.
This popular green roof combines an accessible garden-style roof with potted plants, along with a more traditional, and inaccessible, sedum green roof. It is a good example of a multi-purpose roof that combines social and environmental benefits.
Incentives for green roofs in Toronto:
Currently, the City of Toronto offers an Eco-Roof Incentive program aimed at encouraging green roof implementation in industrial, commercial, or institutional buildings in the city’s designated employment districts. The program provides funding for green roof retrofits on existing buildings, or for industrial and commercial and institutional buildings with a gross floor area of over 2,000 m2. The incentive provides $50/square metre up to $100,000. For more information see www.toronto.ca/livegreen.
Return on Investment:
Green roofs can reduce the cooling costs for the upper floors of buildings, insulate against sound, and, if done properly, can reduce the size of the ventilation system required for the building. For more specific information on the benefits of green roofs, please see www.greenroofs.org.
Angela Loder is a Ph.D. Candidate at the University of Toronto studying green roofs and health.