8 Outstanding Green Roof Examples & Designs in the USA
Green roofs, also called vegetated or living roofs, are an environmentally friendly type of sustainable roofing commercial buildings all over the world are beginning to use. Green roofs are composed of a thin layer of vegetation installed on a traditional flat or pitched roof. They help keep buildings dry and prevent pooling or standing water. Green roofs can even protect your roofing system from harsh UV rays and extend the roof’s lifespan.
A big reason property owners are switching to green roofs is their impact on the environment. Commercial HVAC systems emit high levels of greenhouse gases from fossil fuel combustion. Green roofs have the capabilities to keep the interior of your building cool which means you can use your HVAC system less. This in turn will also lower your energy bill.
Green roofs don’t just support the roofing system, they’re also incredible to look at. There is an assortment of unique green roof designs across the country, some even open to the public. While green roof examples vary, they all contain the same basic components: waterproofing, root barrier, water retention and drainage, growing mediums and plants. Check out some of the green roof designs from innovative architects striving for beauty and sustainability.
Chicago’s City Hall is an 11-story building home to the most famous rooftop garden in the city. The rooftop was first planted in 2000 as a demonstration project for the City’s Urban Heat Island Initiative. The project tested the benefits of green roofs and how they affect temperature and air quality. The garden is home to over 20,000 plants of over 150 different species, mostly prairie plants native to Chicago (shrubs, vines, trees, etc.) These plants thrive in the windy and arid conditions Chicago has each year.
The Chicago green roof improves air quality by using excess carbon dioxide to produce oxygen. The garden also helps conserves energy and reduces stormwater runoff. Since the roof absorbs less heat than a tar roof would, it keeps the City Hall cooler in the summer, and the building requires less energy for AC. Along with the heat, green roofs also absorb water, and City Hall’s vegetated roof can hold up to 75% of an inch of rainwater. The absorption process helps to keep rivers and streams clear of sewer water contaminants from overflow.
In 2003, The 19-floor Solaire building became the first residential high-rise in the US to have a green roof. While in a very urban setting, the architect used green roof techniques to create a sustainable landscape. The rooftop incorporates two types of green roofs into the overall design: an extensive vegetated roof and an intensive green roof system. Extensive green roofs incorporate a shallow layer of substrate that covers a large area. Intensive green roofs have a deep layer of substrate but are confined to smaller areas. The Solaire has groundcovers and sedums and deeper planting beds for an assortment of vegetation including perennials and even bamboo trees. The outdoor space is a perfect place for residents to relax, high above the city.
California Academy of Sciences
As one of San Francisco’s first sustainable building projects, completed in 2008, the California Academy of Sciences hosts a 2.5-acre green roof. The natural landscape is lifted up three stories on top of the building and creates a dramatic living roof unlike any other in the US. The unique protrusions on the roof mold around the interior facilities, office and exhibition halls. The large humps form around the planetarium and rain forest exhibit and dip at the central piazza to provide optimal natural light and air into the center of the building.
During the building process, energy efficiency, green building materials, reduced site disturbance, seasonal irrigation and energy generation were all considered in the design. The seven hills on the roof are meant to embody the seven major hills of San Francisco. The native Californian plants on the roof were selected for their adaptability to seasonal irrigation cycles and to attract butterflies, birds and insects.
The Jacob Javits Convention Center
The Javits Center in New York City became a popular hub for improving the quality of life of employees, visitors and surrounding neighborhoods/ecosystems with the implementation of a green roof. Before the installation of the new 7-acre green roof in 2014, and recently the new 1-acre farm, the Javits center was outdated regarding sustainable design measures. It turned into one of the largest retrofitting projects in US history and lowered energy consumption by 26%.
The rooftop farm hosts over 50 crops and 40,000 fruits and vegetables, all of which will be used for meals in the convention center. Other than the farm, guests can visit the outdoor terrace, glass pavilion, orchard and solar farm that adds 1.2 million square feet to the event space. Before the green roof was designed, the Javits Center was known as one of the deadliest buildings for birds. After the update, bird death has dropped by 90%, and the roof now serves as a habitat for birds, bats and bees. The convention center is a definite must-see for New York visitors and continues to push the boundaries of sustainability.
The American Society for Landscape Architecture (ASLA) implemented a green roof system above its headquarters as part of a demonstration project to showcase the environmental benefits of green roofs. ASLA discovered that the green roof helped decrease energy usage by 10% in the winter months. Over a 10-month period, the ASLA green roof prevented 27,500 gallons of stormwater from flowing into DC’s sewer and stormwater system.
The green roof is open to the public for tours and has had over 5,000 visitors since its installation in 2006. Among those visitors have been educators, grade school, high school and college students, local and federal government officials and international visitors. Check out the 3,000-square-foot green roof and social space for yourself.
Zella Apartments is a 7-story building in Seattle with a beautiful green roof for residents to relax on. The project first broke ground in July 2017 and was completed in late 2019. The roof features a deck with an herb garden, an outdoor kitchen, a dog run and plenty of seating. Rather than using spray irrigation, the apartment complex has set up a drip irrigation system to fine-tune the plant palette. The green roof assists in keeping the apartment complex cooler during the hot summer months and mitigates the urban heat island effect. In addition to the array of plants, the roof also features a solar panel system to help reduce the building’s overall power consumption.
NYC Parks Five Borough Complex
The NYC Parks Borough Complex is home to one of the world’s most diverse green roofs. Randall’s Island, where the NYC Parks building is located, is known for live music concerts and biking trails, but its real gem is on the roof. There are dozens of unique green roof systems planted side-by-side on this one roof. The green roof uses some of the world’s most cutting-edge technologies and best practices, containing over 25 different systems across 29,000 feet. Each green roof run by NYC Parks helps to reduce the city’s heat island effect, decrease energy costs, improve air and water quality, sequester carbon and provide a safe habitat for urban wildlife.
Unlike most green roofs across the country, the Parks’ roof acts as an experimental station for green roof design and construction. The Parks team is able to monitor and compare the performance of many different green roof systems in one location. If you’d like to see the roof yourself and learn about urban green roof benefits, you can schedule a tour through the NYC parks department.
Al Johnson’s Swedish Restaurant & Butik
Al Johnson’s, all the way up in Door County, Wisconsin is renowned for its unique green roof. While most green roofs act as natural habitats for birds and insects, this green roof is home to a much bigger mammal: goats!
The first roof was installed in 1973 and was recently replaced in 2011 due to age. Some grass roofs use up to 12 layers of materials but Johnson’s keeps it simple with about six inches of soil and sod topped over a plywood base. The roof has a new membrane for waterproofing and a soil retention layer covered by a drainage mat, but those are the only significant changes from the original roof system. Witness the spectacle for yourself by dining at Al Johnson’s, or check out their goat cam online.
Why Choose A Green Roof?
While green roofs might seem a little odd in everyday architecture, there are several reasons why they make a good investment strategy.
- Economic benefits
Green roofs may improve the value of your property, especially in urban areas with minimal vegetation.
- Water management
Green roofs help maintain water runoff and retention. Rainwater runs off buildings and into the storm sewer system. Any contaminants on the roof could be picked up and deposited into rivers and streams from sewer overflow. Green roofs will retain water in the plants to prevent this from happening.
- Environmental incentives
With the temperature in cities often higher than in rural areas, green roofs play a hand in reducing the urban heat island effect. Green roofs absorb the heat and also use solar radiation to evaporate water, lowering temperatures on the roof.
- Unique space for renters
When green roofs are accessible, they provide a comforting and enjoyable atmosphere for the building’s occupants. Rooftop gardens can be an aesthetically pleasing environment for meetings or recreation. Some green roofs grow herbs and vegetables that can be used by the property owner.
- Extends life span of the roof
The roofing materials underneath a green roof system are protected from direct ultra-violet radiation and extreme temperatures. The roof requires less overall maintenance and saves property owners money in replacement costs. Well-maintained green roofs can last 2 times the amount of an average roof.
Roofed Right America provides green roof installation services to communities across the US. Check out some of the green roof projects we’ve completed in the past. If you’re interested in designing a green roof, contact our roofing contractors today.