Monday, May 15, 2017

Effective Green Roofs for Healthier Cities

In cities with dense urban populations like New York and New Jersey, it is common to witness large amounts of emissions and waste. These emissions have the possibility to wreak havoc on not only the economy’s health but a person’s health as well.  A great way architects can combat this and increase biodiversity and sustainability is by designing buildings with green roofs aka “eco-roofs”.

Buildings by nature are intrusive and obstructive to the environment. They disrupt the natural flow patterns and strain our natural drainage systems. Green roofs can conceptually serve as a replacement for the ground occupied by the building (see green roof concept below).

Typically, a green roof includes a waterproofing membrane layer that protects the building, soil, and plants overlying a traditional roof. 
Detailed version of the layers in a green roof

Sustainable Benefits
Not only are green roofs attractive but it is an important way to solve environmental issues such as, energy consumption, improving water and air quality, lowering temperatures on the roofs, and lessening the impact of the urban heat island effects. Below I will go more into detail about each of these issues and how green roofs combat them.

Energy Consumption
Conventional roofs, also known as, black roofs derive from petroleum based black tar or rubber. These materials absorb energy from the sun and can reach high temperatures up to 150°F in the summer. If you live in a building where your air conditioning bill skyrockets in the summer this might be a reason why. The great thing about green roofs is that they help combat this problem by absorbing less sunlight, in comparison to black or white roofs, through a process called evapotranspiration.  In addition to this, they also have the capability to act as an insulator that reduces heat flux and takes the heat from the building’s exterior to the interior through the roof by up to 72%. 
Water Quality
When storms occur, alternative roofs can create runoffs flowing into sewer systems and this helps with water pollution and flooding.  Green roofs reduce the amount of storm water runoff and delays the time at which runoff occurs. Furthermore, the soils and plants absorb rainwater, lessening the impact on storm drainage. If native plants are used, they may require little to no maintenance. 

Air Quality
New York City is full of smog but plants are those helpful friends that remove air pollutants no one wants like carbon dioxide and carbon monoxide. Green roofs can create healthier cities because it contributes to smog reduction using the plants that are on the roof. 

Urban Heat Island Effect
Planted roofs can lessen the impact of the urban heat island effect by decreasing the rates of heat-related illnesses, improving air quality, and further insulating the roof, which improves a building’s energy efficiency.  

Reduce Sound / Longevity
A green roof provides a natural layer of protection for buildings and insulation that extends their life and thereby reducing waste and frequency of replacing roofs. Unlike conventional roofs, green roofs absorb sound and reduce the noise transmitted around dense populations. 

Aesthetic Impact
In addition to the economic benefits listed above, there are so many aesthetic positives that can accompany a green roof. Green space can serve as a quiet refuge within the sometimes chaotic urban environment, allowing users to connect back to nature. Aesthetically, green roofs can improve the views from neighboring buildings. I would much rather see a beautiful view consisting of someone’s garden instead of roof membranes, and unsightly mechanical equipment any day. Look at the beautiful aerial view of the green roof at Chicago City Hall.

Chicago City Hall Green Roof

Financial Consideration
The added cost of the green roof can partially, if not fully, offset through lower utility rates, tax benefits, and higher market values. It becomes a highly marketable and visible amenity; it is cost effective in the long run and can help you save money. These are among the many reasons that we are such a passionate proponent of green roofs and attempt to use them in our projects whenever possible. Like in our project 93 Bright (see picture below)

Green roof at 93 Bright

Our building 93 Bright includes a green roof that is a great amenity for tenants and benefits from its sustainable qualities. JMA loves seeing greenery in the city and finds it so important to bring nature back into large metro areas. Besides green roofs being attractive, it provides many benefits to the environment and it helps improve our cities. Green roofs are the ultimate win-win situation for everyone involved so don’t hesitate go green with the rest of New York.


United States General Services Administration. "The Benefits and Challenges of Green Roofs on Public and Commercial Buildings." United States General Services Administration, May 2011. Web. 12 May 2017

Chicago City Hall Green Roof Image Source: TonyTheTiger, Chicago City Hall Green Roof. 2008, Digital Image. Available from Wikipedia.

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