Green roofs, or what is also called living roofs, are underutilized spaces in an urban environment, yet any landscape, garden or park can be installed on a building or structure. Over the past 30 years, green roof constructions have become part of urban architecture in many cities around the world.
Modern green roofs were first developed in the 1960s in Germany. In the course of recent years, roofs have turned into the focal point of quiet yet steady progress through the use of green roof technology in Europe. Cities such as Stuttgart in Germany and Copenhagen in Denmark are known for their many green roofs. About 20-25 percent of the roofs in Stuttgart are green and around the country 10 percent of green roofs. These successes were largely achieved through government incentives.
France Mandates Green Roofs
In 2015, France passed a law that mandated all new commercial buildings built in the country to be at least in part covered by green roofs or solar panels.
The green roofs are turning into widespread constructions of buildings around the world. These types of green roofs have many interesting features, from lowering the maintenance cost to reducing stormwater runoff.
One of the main reasons why these roofs have become widely popular is their ability to minimize the urban heat island effect. According to research green roofs can reduce the temperature of cities by 1-2 degrees Celsius.
It is very important that properly planned green roofs can imitate natural processes. Thus, even the thinnest green roof can adequately absorb most of the rainfall, reverse the effects of urban heat islands and create a natural habitat for urban-dwelling animals. They also properly insulate structures, providing energy efficiency, extend the life of the roofing layer, increase the value of a real estate and significantly improve the urban design.
Green Roof Buildings in North America
While Europeans have been getting a charge out of these advantages for a considerable length of time, Americans have only recently started to grasp them. Toronto was the first city in North America to pass a Green Roof By-law in January 2010 that required green roofs must be incorporated into the structure of every single new building.
With the population growth, it is becoming increasingly difficult to discover green space in the city. Toronto is battling this with its recently delegated Green Roof by-law. Toronto City Council mandated by-law is an incredible achievement for green living.
“Toronto’s by-law provides a new opportunity to strengthen the emerging practice of integrated green building design,” said Steven W. Peck, the president of Green Roofs for Healthy Cities. “[It] breaks new ground on how to structure a mandatory green roof requirement.”
Although the United States does not have nationwide green roof law, there are financial incentives and initiatives/programs that promote green roofs in many cities across the country, including Chicago, New York, Portland, and Washington. In addition, green roofs provide LEED certification, environmental remediation and extend the service life twice as long as conventional roofs.
Chicago City Hall Green Roof
One of the world’s most outstanding green roofs is Chicago’s City Hall that is a mix of intensive and extensive green roofs. Finished in 2001, the rooftop garden was intended to test various sorts of green roof systems, warming and cooling benefits, achievement paces of local and non-local vegetation, and decreases in water spillover.
The three systems coordinated into the plan incorporate lightweight soils at 4, 6 and 18 creeps top to bottom. These changing green roof systems are perceived individually as extensive, semi-intensive, and intensive green roofs. Soils were created utilizing lightweight soil blend rules created in Germany in the course of recent years.
Like every green roof, the City Hall rooftop garden improves air quality, preserves vitality, diminishes tempest water spillover and reduces the effects of urban heat islands. The garden’s plants reflect heat, give shade and help cool the encompassing air through evapotranspiration, which happens when plants discharge or come to pass water through pores in their leaves. The water draws heat as it dissipates, cooling the air all the while. Plants additionally channel the air, which improves the air quality by utilizing overabundance carbon dioxide to create oxygen.
The plantings are composed in a sunburst design, which regards the evenness of the memorable City Hall and gives an arrangement for organizing gatherings of plants over the three distinctive roof systems.
In total, the City Hall planted more than 3,500 species of plants and more than 150 species of animals in the 3,530-meter space.
New York City Green Roofs
In New York City, there are about 730 buildings covered with green roofs. Although this represents only 0.1 percent of the city’s 1 million buildings, their number is increasing every year. The Javits Center has the largest green roof, while smaller green roofs cover private homes, schools, and farms such as Brooklyn Grunge.
The Javits Convention Center is home to NYC’s largest green roof, built-in 2014. The nearly 7-acre green roof features 14 different varieties of Sedum plants. The green roof reduces energy consumption by 26 percent and prevents about 6.8 million gallons of water runoff every year. In addition, the roof provides habitat for more than a dozen different species of birds.
Green roofs help NYC combat the urban heat island effects, which are expected to worsen with climate change. According to the Centers for Disease Control and Prevention, more Americans die from the effects of the urban heat island than from other natural disasters.
New York City’s goal is to reconstruct old pre-war buildings to improve energy efficiency in order to reduce greenhouse gas emissions from buildings. Local laws set carbon limits and heavy fines starting in 2024.
The introduction of this lightweight green roof construction technology is expanding worldwide as cities from around the world learn about the benefits of vast extensive green roofs. In 1999, the Green Roofs for Healthy Cities association was founded in North America, which has held annual Green Roof conferences since 2003.
Thus, green roofs have great advantages for growing cities in combating the effects of urban heat islands, greenhouse gas emissions from buildings and providing a habitat for birds and animals. Green roof technologies are becoming more affordable and efficient. Cities with a growing population should become more sustainable and resilient to climate change and other challenges of the future.
What about the city where you live? Is it sustainable and has joined green roof initiatives? How do you want to see it in the future? Please leave your comment below.