While vegetated roofs can manage stormwater, improve air quality, and increase biodiversity, installations of the roofs declined by 12% in 2014. This is a marked change from 2013’s 10% increase. A variety of factors could be responsible for the drop in implementation. A lack of government stimulus funding, which helped fund many of the previous years’ installations, is the most likely cause. Extreme temperature fluctuations in the U.S. have also delayed project installations.
Despite declining implementation rates, more projects were installed in private spaces than on public property in 2014, a significant shift from last year. The study also ranks the top North American cities for green roof usage. Washington, D.C. takes the top spot with Toronto, Philadelphia, Chicago, and New York City rounding out the top five. These leading cities have supportive policies and programs that incentivize green roof implementation.
The study, conducted by the Green Roofs for Healthy Cities initiative, measured data from 27 corporate members and found that extensive roofs (those using 6 inches or less of growing medium) are still vastly more popular than their intensive counterparts. According to the study’s authors, the discrepancy is most likely due to the higher cost and increased maintenance associated with intensive installations.
Looking to keep your vegetated roof in tip-top shape? Keep pests away with these Four Tips for Pest Control on Green Roofs.