WC3 Design has worked on many green roof projects which provide many economical, environmental and physical benefits. One of the several green roof projects we have worked on is the Mima Roof Terrace.*
Green Industry Trend
Most buildings are covered with black slates of nothingness: The black asphalt, tar, and gravel-covered roofs radiate heat and further rushing water during storms. Ever popular in Europe, the new green roof trend is sweeping the United States. Green rooftops appeal to homeowners, businesses, and even cities, as an environmentally friendly way of dealing with conventional roof issues. In addition, these living roofs now make a previously vacant space beneficial and enjoyable.
Planting a Roof
The conditions on a roof are very different than the conditions of a regular landscape. Roofs endure harsh environments with extreme wind, heat, exposure, and limited soil depths. These are factors to take into consideration in order to create an effective and safe growing environment.
The type of plant to be grown needs to be appropriate for the setting and environment. Different plants require different depths of soil, but having to deep a soil or too many plants can cause a roof to collapse. Determining what the owner desires will help you design a better landscape. Determine goals such as rainwater harvesting, gardens or ornamental plantscapes.
For all green roofs, a waterproofing membrane is built into the surface. A growing medium is layered over the membrane to act as a “living wall” that the vegetation can grow into.
There are many benefits to green roofs. Benefits are public, private and design-based.
Green roofs last longer than conventional roofs and create a natural installation, which reduces energy costs. The greater insulation offered by green roofs can reduce the amount of energy needed to moderate the temperature of a building, as roofs are the sight of the greatest heat loss in the winter and the hottest temperatures in the summer. This could reduce demand on power plants, in turn reducing the amount of CO2 and other pollutants being released into the air.
For the Public
By replacing unused harsh roofs, green roofs create peaceful retreats for people and animals. Adding green roofs is an easy and effective strategy for building the look and appeal of a city. Green roofs can serve as community gardens, commercial spaces or recreational spaces. Green roofs can sustain a variety of plants and invertebrates, and provide a habitat for various bird species. An installation of plants serves as a great noise barrier and provides a tranquil space.
Because of the greenery, living roofs significantly improve stormwater management. On average, green roofs retain 70-90% of precipitation during the summer and 25-40% during the winter. This helps prevent runoffs and flooding, which in turn, lessens the need for complex and expensive drainage systems. Green roofs reduce the amount of stormwater runoff and also delay the time at which runoff occurs, resulting in decreased stress on sewer systems at peak flow periods. Green roofs not only retain rainwater but also moderate the temperature of the water and act as natural filters for any of the water that happens to run off.
Green roofs improve air quality by reducing the distribution of dust, particulates, gases, and smog in a city. This occurs when plants on green roofs capture airborne pollutants. This can play a role in reducing greenhouse gases.
Green roofs help lessen the Urban Heat Island Effect, a condition in which city and suburban developments absorb and trap heat. Through the daily dew and evaporation cycle, plants on vertical and horizontal surfaces are able to cool cities during hot summer months. The light absorbed by vegetation would otherwise be converted into heat energy.
Green roofs can also contribute to landfill diversion in several ways. First, by using recycled materials in the growing process. Prolonging the service life of heating and ventilation systems contributes as well. Green roofs also, prolong the life of waterproofing membranes, reducing additional waste.
Green roofs can increase a building’s marketability. They are an easily identifiable symbol of the green building movement and can act as an incentive to those interested in the multiple benefits offered by green roofs. Green roofs have increased property value due to increased efficiency. Buildings with green roofs have also found it is easier to recruit employees. Lower employee and tenant turnover are also a response to green roof buildings.
Due to the numerous benefits of green roofs, many homeowners, businesses, and cities are implementing them. As designers, we appreciate the art, craft and environmental influences green roofs have. One of the several green roof projects we have worked on is the Mima Roof Terrace.
*Mima Roof Terrace is a rooftop environment to serve as “the Village Green.” It was designed by HM White Site Architects and won awards with the New York ASLA Chapter and achieved LEED Gold Certification. The site was intensely planted thereby supplying several differing atmospheres. Even with low water pressure, we were able to design an irrigation system that met the site vegetation’s needs and yet is very efficient and inconspicuous.