Visibly Greener

by Kasia Janczura

Just recently the Center for Architecture hosted Work in Progress: Green Walls exhibit, supporting the successful implementation of green rooftops in urban areas. The trend is growing from plant-covered rooftops to fully planted walls, making landscape architecture take on a different approach to ensure plenty of greenery. Green buildings are a great way to promote energy efficiency while keeping the aesthetics fresh and green: it’s a two-in-one deal.

According to the United States Environmental Protection Agency (EPA), urban areas with more than 1 million inhabitants are often referred to as “heat islands,” where the mean day air temperature is 1.8-5.4˚F warmer than that of surrounding areas. In the evening, the temperature difference can reach over 20˚F. The higher temperature has negative externalities, such as increased energy consumption, increased greenhouse gas (GHG) emissions, additional health problems, and lower water quality. Planting building rooftops and walls helps decrease this temperature jump, as described in Reducing Urban Heat Islands: Compendium of Strategies.

Studies have shown that temperatures of planted rooftops can be up to 75˚F cooler than those of dark, conventional roofs, helping to save thousands of dollars on energy expenditure. As with many novice infrastructural improvements, the initial construction costs of green rooftops slightly outweigh those of conventional rooftops. With increased interest in making cities visibly greener, however, the average cost of construction will lower, making eco-roofs a better option for investors. Likewise, studies indicate that benefits surpass the costs, making green rooftops the right long-term investment option. Many of New York City’s buildings are taking up this solution, including Bank of America Tower at One Bryant Park, the Rockefeller Center’s roof gardens, the Helena residential building, and the new Silhouette residential project in Brooklyn. Portland, Oregon, for example, wants to expand its rooftop coverage to 40 acres by 2012, from today’s 6 acres of green rooftops.

With the popularity of green rooftops growing, green walls might be the next revolutionary approach to sustainable building development. The trend is popular in Asia and Europe, and can contribute to LEED points, as indicated in an article in Building Design and Construction. The American Society of Landscape Architects (ASLA)'s role in providing for a sustainable environement is vital in our transition to greener options, giving landscape architects a greater part in designing buildings.

Once again, green initiatives reenter construction agenda, ensuring that ecologically aware investments translate to an ongoing triumph. Not only can buildings save on long-term energy investments, but can successfully market their socially responsible business choices and promote a healthier living situation to their residents.