Going Green From the Top Down

Large, populated cities are increasingly becoming bereaved of green spaces. The protest of many incited increased regulations and slowed their disappearance but haven't stopped it entirely. A new trend has emerged recently that has seen the introduction of more green spaces of a "higher order", giving back many in urban populations the enjoyment of experiencing nature, while also presenting additional environmental and financial benefits.

Rooftop gardens and lawns are increasing in number in downtowns across America, and for good reason.

Environmental Benefits

Rooftop gardens can have a very tangible effect on their immediate environments and, if there are enough of them, on entire cities as well. They improve the air quality by providing more oxygen and absorbing pollutants. They also remove nitrogen from rainwater runoff, and can help drainage systems by retaining up to 80% of rainfall and delaying peak flow times. They have also been shown to mitigate the urban heat island effect to a significant degree. This is a phenomenon that causes higher temperatures in cities due, in part, to the absorption and re-emission of heat from urban infrastructure. Studies have shown rooftop gardens can reduce the heat of a roof by up to 50° in the summer. They also help to insulate the building, lowering energy usage and the resulting carbon emissions.

Financial Benefits

Although rooftop gardens may be more expensive initially, they can be an investment that pays dividends for years to come. In some cities, there has even been tax credits given of up to $100,000 to businesses and residencies that convert or build their roofs into rooftop gardens, to offset the investment cost. Programs like this are likely to be replicated in many more cities given their success thus far. Once the garden is built, you can expect lower energy costs, as noted above, the garden works to insulate the building, keeping it cooler in the summer and warmer in the winter. Rooftop gardens can also extend the life of a roof by up to 200%! On top of that, when it comes time to sell, the green space on the roof increases re-sell value significantly.

Social Benefits

Companies that have provided green spaces on the rooftops for their employees report higher job satisfaction and employee retention. It helps improve the morale in a work environment and makes a great venue for company parties. The combination of the garden aesthetic and the view of a city is truly a unique experience. If installed on apartment buildings or condominiums, it would help foster a community in the building that is often lacking when compared to traditional neighborhoods. It would encourage tenants to stay longer and reduce the time in between occupancies. They have been used in hospitals as well, and to great effect. The picture above is of the Healing Garden on the 11th floor of the Boston Children's Hospital, the garden helps the children and parents enjoy the outdoors even during treatment. The garden offers an expansive view of the city and is a great way to boost the spirits of patients even in difficult times.

Drawbacks

While rooftop gardens have a myriad of benefits, there are of course, some reasons to pause, when considering one. The initial cost can be a deterrent, with new construction, this is less of a concern, the average cost per square foot is only about $5 more than traditional means. If you are converting the structure's roof into a rooftop garden, you can expect far greater expenses, in most cases. With more cities realizing the value of rooftop gardens we can expect similar tax programs, as discussed above, to become more prominent, thereby mitigating this con to some degree.

Another issue that can turn people away from the idea of rooftop gardens is the maintenance required. Proper care for the garden can be extensive, you may have to replace the growing media, there may be need for watering systems, especially in dry climates, and pest management becomes an increased concern. Many of these concerns can be addressed in the planning stages by the selection of compatible plants for the environment and situation, but even still the maintenance would be greater than typically required of a traditional roof.

Moving Forward

Rooftop gardens offer unique benefits especially for urban environments. With the growing push to beatify cities in tandem with the increased environmental consciousness, their number has grown and continues to grow. Advances in technology has made the design and construction more manageable and will likely decrease cost in the coming years.

Have you ever enjoyed the view of a rooftop garden? Do you think implementing them offsets the loss of green spaces in cities, or would you like to see more protection of traditional parks? Let us know in the comments.