The wide-range of benefits offered by green roofs have encouraged increasing numbers of municipalities and building owners alike to invest in this architectural sustainability solution. Aside from fighting air pollution and mitigating urban heat island effect, these roofs also implement savings on energy costs and offer spaces for pollinators and other wildlife. With these and other benefits, it's surprising why there aren't more green roofs. A recent article written by senior lecturer of urban geography Michael Hardman and research fellow Nick Davies from the University of Salford highlights the obstacles and opportunities faced by proponents of the growing green roof trend.

In their detailed piece from The Conversation, the researchers point out two primary factors affecting the success of these sustainable design options: buy-in from city authorities and institutions and a need for further research on green roof variations for different types of rooftop spaces. 

Speaking to the growing green roof market in the UK, Hardman and Davies explain, "A recent report in the UK suggested that the green roof market there is expanding at a rate of 17% each year. These increasingly radical urban designs can help cities adapt to the monumental challenges they face, such as access to resources and a lack of green space due to development." 

According to the article, American cities like New York and Chicago have allowed or required green roof designs for new projects, while other global cities like Paris, Singapore, and Stuttgart have enacted even more impressive examples of these urban design alternatives. Stuttgart, for example, has been coined "the green roof capitol of Europe," the authors state, with examples of multiple matured green roofs located throughout the downtown area of that city. 

While it may be easy to list the benefits of these roof types, however, Hardman and Davies quickly explain in their article that in order for green roofs to "become the new normal" for developments, public authorities and private investors must all be on board, a process that includes developing new financial as well as maintenance models. "Those responsible for maintaining buildings may have to acquire new skills, such as landscaping, and in some cases volunteers may be needed to help out," the researchers write. 

The two continue to outline, "Other considerations include installing drainage paths, meeting health and safety requirements and perhaps allowing access for the public, as well as planning restrictions and disruption from regular activities in and around the buildings during installation."