Raising the Green Roof

green roof at the  California Academy of Science s

It’s time that we put more green roofs over our heads. 

Green roofs have the power to make a quantifiable impact on buildings and the built environment. Conventional roofs in the U.S. are typically made out of slate, metal, plastic, or even clay shingles, while green roofs improve those materials with a layer of vegetation. Installing a green roof over a conventional roof leads to numerous potential benefits for building occupants and the surrounding community, like adding green space and reducing the heat island effect in cities.

We took a look at different green roofs across the U.S. to better understand these benefits as well as the range of diversity that exists in green roof function and design. Check out some of the most notable roofs we explored below!

Renewable Energy and Building Efficiency at the California Academy of Sciences

Located in San Francisco, this building on a hilly rooftop has skylights, fields of vegetation, a viewing space for visitors, and solar panels that line the periphery. According to the California Academy of Sciences, the solar panels provide at least 5 percent of the building’s electricity for the year, saving the atmosphere from 405,000 pounds of greenhouses gases and utilizing on-site renewable energy. 

The roof has also been designed to reduce the amount of energy needed for heating and cooling—the vegetation acts as insulation, while clusters of circular skylights open and close during the day for ventilation and fresh air flow.

Stormwater Management and Urban Agriculture at the Javits Convention Center

The Javits Center in New York City is home to a 297,000-square-foot rooftop covered in sedum, a hardy ground cover in the succulent family. Sedum provides habitat for birds, bats, and bees, and is well known for its capacity to retain water. Big storms in cities like New York often lead to polluted runoff that overwhelms the local sewer system. Adding vegetation like sedum mitigates these issues since the Javits Center is able to retain about 6.8 million gallons of runoff per year.

The Javits green roof is famous for being the second largest in the U.S. and will be expanded to include a rooftop farm by 2021. The “rooftop-to-table” farm aims to produce 40,000 pounds of fruits and vegetables annually, which will be used in the convention center’s kitchens.

 Plant Biodiversity and Educational Space at the Chicago Botanic Garden

Committed to plant conservation, the Green Roof Garden on top of the Chicago Botanic Garden in Chicago grows both regional and national native plants, as well as some exotic ones – over 40,000 plants and 200 different species thrive on this green roof. One of the biggest benefits of using native plants is creating habitat for local species and reducing outdoor water use for irrigation.

This green roof serves as an outdoor classroom for thousands of visitors each year. Designed to be a center for research and environmental education, scientists can experiment with which plants are best suited for rooftop environments while the public can learn about the flora.

--

It’s clear that green roofs can serve many functions—from supporting local plant species to reducing energy use or preventing sewer overflow from storms. They are also just one of the many potential features of a high-performance building.

To learn more about high-performance buildings and what makes them unique, consider taking a GPRO course or attending an Urban Green Council event! Reach out to gpro@urbangreencouncil.org for more information.

THE JAVITS CENTER’S GREEN ROOF IS THE SECOND LARGEST IN THE U.S.

THE JAVITS CENTER’S GREEN ROOF IS THE SECOND LARGEST IN THE U.S.