Green roof at 50 United Nations Plaza, a habitat in the sky
By Amy Pevzner
The 14,000-square-foot vegetated roof spans the central roof deck at 50 UNP and is the first of its
kind in the region.
Did you know that the roof of 50 United Nations Plaza (UNP) in San Francisco is now home to more than 30 different plants that provide a safe haven for bird, butterfly, and insect populations? Commonly referred to as a "planted," "living" or "green" roof, the 14,000-square-foot "semi-intensive" vegetated roof spans the central roof deck at 50 UNP and is the first of its kind in the region.
GSA has long understood the many benefits of integrating nature into architecture in this way. In fact, green roofs have been a part of GSA’s national inventory since 1975. Just recently gaining traction over the past few years, several more GSA green roofs have begun to spring up in Washington, DC, Chicago and Portland. Today, GSA maintains well above two million square feet of green roofs and this number is rapidly growing. Green Roof Tracker >
“More than just an add-on, our green roof is an integrated design strategy that can greatly impact a building’s operations, its community, and the environment in numerous ways,” said Monsy Agleham, 50 UNP project manager.
Green roofs provide many lasting benefits that include:
Extended life of roof membrane. A typical green roof lasts 40+ years before requiring replacement, where the life of conventional roof is 10-15 years. Cutting the frequency of roof replacement in half saves taxpayer money and diverts waste from landfills.
Enhanced performance of nearby equipment. A green roof reduces extreme temperature swings by 30 degrees while capturing particulates in the air. More consistent temperature ranges and cleaner equipment surfaces improve and extend the performance of nearby equipment (PVs and HVAC), thus contributing to overall reductions in equipment maintenance and capital costs.
Stormwater management. A typical green roof reduces stormwater overflows by up to 75 percent while significantly slowing stormwater runoff times. In order to reduce water treatment costs and frequency of sewage overflows into nearby waterways, many municipalities are beginning to require a property to manage its own stormwater. Green roofs enable property managers to effectively manage stormwater onsite without requiring square footage outside of a building’s existing footprint.
Improved water and air quality. Excess carbon and other emissions contribute to climate change, pollution, and health concerns. Vegetation effectively cleanses the air and water, while paved surfaces capture heat and restrict the necessary flow of water. Rooftops make up 30 percent of all paved surfaces in a typical city, so greening them capitalizes on an otherwise untapped opportunity to significantly improve our environment and mitigate effects of urban heat islands.
In addition, green roofs:
- Provide much needed habitat to support plant and animal biodiversity
- Reduce building energy requirements and minimize peak energy demands
- Reduce noise pollution by .85 decibels
- Increase values of a property, as well as those of its neighbors