A green roof has been installed on New York’s most iconic skyscraper, The Empire State Building. The 381-metre office tower now includes four Xero Flor Green Roofs that cover 9,100 square feet across three floors.
The two largest green roof areas are on the 21st floor, feature outdoor furniture in a patio-inspired space and are open to office occupants. The smaller roof sections are on the 25th and 30th floor.
The Xero Flor system used for the roof is made from lightweight pre-vegetated mats that are rolled and joined together to create a “green carpet”.
“The green roofs decrease stormwater run-off and improve water quality in New York’s waterways, moderate the urban heat island effect, filter dust and other air pollutants, and store carbon dioxide and other forms of carbon to reduce greenhouse gases,” said Clayton Rugh, Ph.D, general manger and technical director of Xero Flor America (XFA).
XFA’s green roof vegetation is grown at independently-owned local farms. The vegetation grown for this project was specifically selected to survive in Manhattan’s urban climate. The plants will work to cool the Empire State Building by absorbing solar gain and prevent carbon dioxide emissions.
In terms of the materials, the textile based design of the roof mats are design engineered in Germany, though XFA produces the system components of US-based projects within America. The company recently completed green roofs at the Javits Convention Centre in Manhattan, with Rugh confirming XFA greenery now covers approximately 530,000 square feet of rooftops across New York City.
The installation of the green roofs on the Empire State Building is part of a larger initiative that includes a $550 million capital improvement project to restore and retrofit the iconic skyscraper.
The initiative was launched by former US President Bill Clinton and New York Mayor Michael Bloomberg in 2009 and aims to boost the building’s sustainable credentials and focus on energy efficiency for the skyscraper, which dates back to 1931. The building currently holds a LEED Gold rating according to the Council of Tall Buildings and Urban Habitat.
“With its comprehensive energy efficiency retrofit program, the Empire State Building has attracted new tenants who derive direct economic benefits from our energy efficiency program and who recognise the value of healthy workplace environments for attracting and retailing talented employees,” said Tom Durels, executive vice president of Malkin Holdings, L.L.C., the firm that supervises the Empire State Building. “The new green roofs further demonstrate our sustainability leadership and add appealing green space that enahces the value of office space for our tenants.”
According to the Empire State Building website, the retrofit motivated several large such as LinkedIn, Shanska, LF USA, Coty Inc., The Federal Deposit Insurance Corp. and Shutterstock to move in.
In June, the Empire State building also revealed that in 2011, the building exceeded its one-year energy efficiency guarantee by five per cent, saving $2.4 million in energy costs. The following year, it exceeded its goal by nearly four per cent.
“Once all tenant spaces are upgraded, the building will save $4.4 million a year, at least a 38 per cent reduction of energy use that will cut carbon emissions by 105,000 metric tons during the next 15 years,” an Empire State Building press release reported this year.
The green roofs will contribute to the skyscraper's ongoing energy reduction goals. In addition to reducing energy requirements, green roofs can also reduce noise pollution and offer food production possibilities.
With rooftop space available on approximately 12 to 13 per cent of the land in New York City, the Empire State Building sets an industry benchmark demonstrating the opportunity to convert Manhattan’s most historic skyscrapers into energy efficient structures.