Today, the topic of starting to actively use the roofing surface appears frequently in the ongoing dialogue about how to make architecture and the building industry more sustainable. In fact, green roofs are popping up on an increasing number of buildings around the world. Usually made with hardy varieties of succulents, grasses, wildflowers and herbs, planted roofs require numerous technical challenges – a typical section to allow proper plant growth would indeed require several structural layers, including an impermeable membrane and layers for drainage, insulation and filtration.
Green roof architecture in 15 projects you need to know
From private residences to cultural institutions, stations and museums: a collection of architectures that have employed the vegetal element in architectural composition through technical challenges and client demands.
Photo Alessandro Sartori
Photo Barbara Palazzi
Photo Lorenzo Zandri
Photo Lorenzo Zandri
Photo María González
Photo María González
Courtesy Barbican Center
Courtesy Barbican Center
Courtesy Emilio Ambasz
Courtesy Emilio Ambasz
Photo Tim Griffith
Photo Tim Griffith
Photo Pietro Savorelli
Photo Pietro Savorelli
Photo Jan Kofod Winther
Photo Jan Kofod Winther
Photo Ronald Tilleman
Photo Ronald Tilleman
Courtesy Brooklyn Grange
Photo Shinya Kigure
Photo Shinya Kigure
Photo Qingyan Zhu
Photo Qingyan Zhu
Photo Shephotoerd
Photo Shephotoerd
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- Romina Totaro
- 09 April 2024
The benefits contribute to better stormwater management and reduce the effect of urban heat islands, as plants play a cooling role during the hot summer months. Green roofs can also be surprisingly effective against pollution, as plants' photosynthesis improves air quality. Because of their insulating effect that provides additional protection against solar radiation, green roofs can also reduce the amount of energy needed to regulate building temperatures, whereas conventional roofs lose heat in winter but heat up in summer.
But the rush toward these economic and environmental benefits, could cause people to lose sight of their compositional value within architectures. Incorporating greenery within the building structure has always been a challenge dear to designers, even before climate consciousness.
Through this collection we therefore review fifteen relevant examples, architectures that have been able to address the “green roof” theme in innovative and intelligent ways, from historical case studies to recently built projects.
Starting from the Milanese rationalist tradition, we find one of the earliest Italian examples in the multifunctional complex in Corso Buenos Aires designed by BBPR in ‘67.
Due to the client‘s request to include a supermarket, which with its extension occupies almost the entire ground floor, the designers are forced to give up the classic courtyard and choose to work on the difference between the main street-the busy Corso Buenos Aires-in order to insert parceled vegetation between the stepped terraces of the various apartments. Since a parking lot for customers is placed on the roof of the supermarket, to evoke an absent garden the designers then placed long concrete beams with a V-shaped section, pots in which lush shrubs were planted that have the dual function of sheltering the cars from the sun and hiding the view of them from the apartments.
Part of the Opération Jeanne-Hachette, the iconic Brutalist complex consists of 40 social housing units, offices and stores that are mixed on different levels composing a kind of pyramidal structure.
Public and private spaces are mixed here, and roofs are also used in their third dimension as a design device – not only as pedestrian flat surfaces but also as playful platforms invaded by wild vegetation. The theme of triangles and the green element shaped the strategy of lightening the presence of concrete, to mix nature and architectural structure.
The abandoned cement factory on the outskirts of Barcelona once symbolized Spain’s post-World War II industrial boom, housing the country’s tallest smokestack.
Bofill, celebrating the building’s volume, provided a green plinth to these volumes, creating the effect of a huge concrete building structures floating in the jungle. The green roof also gives a new function to the large portion of the existing factory's unused concrete roof, creating a beneficial monoclimate that cools and humidifies the surrounding air.
The Barbican Estate is widely recognized as one of the most important examples of Brutalist architecture, and it still represents a utopian ideal for London metropolitan life. Indeed, with its rough concrete surfaces, hanging gardens, and trio of skyscrapers, the Barbican offered a new vision of how high-density residential neighborhoods could be integrated with schools, stores and restaurants, and world-class cultural destinations.
The original design aimed to create a self-contained "urban village," with residential and public spaces completely separated from vehicular traffic. Through an interesting section design, most of the landscape elements, including water bodies, are inserted above the parking lots and recreational facilities below.
Considered the father of green architecture, Emilio Ambasz tested the technical limits of combining architecture and vegetation in so many of his projects. In the case of the Prefectural International Hall, the architect dedicates the entire tiered roof entirely open to the public as a vegetated surface.
In fact, the structure looks like a hybrid: a building with elegant, understated facades on three sides and a mountain-like public park on the fourth side, to the south, which can be defined as the roof, the front, the back or rather the face of the building. There are 14 terraces, one on each floor, all accessible and interconnected by zigzag stairs that run from ground level to the upper belvedere, 60 meters above. Climbing up, down and across the lush banks, visitors can admire pools and waterfalls surrounded by 50,000 plants of more than 120 species.
Renzo Piano's California Academy of Sciences is one of the largest natural history museums in the world. The architecture consists of two buildings, each with freestanding glass domes about 27.43 m high, housing the planetarium and the living rainforest.
The entire 37,000-square-meter complex is like a piece of parkland cut out and raised 10 m above the ground. This “living roof” is covered with 1,700,000 selected native plants planted in specially designed biodegradable coconut fiber containers. The roof is flat on its perimeter and, like a natural landscape, the topography becomes more pronounced as it moves away from the edge. The domes are then punctuated by a series of skylights that open and close automatically for ventilation.
Soil moisture, combined with the phenomenon of thermal inertia, significantly cools the interior of the museum, thus obviating the need to air-condition the public areas on the ground floor and the research offices along the facade.
Surrounded by the unique Chianti hills, halfway between Florence and Siena, Archea Associati's architecture challenges through hypogeal architecture the theme of roofing.
In fact, the Antinori Winery is first and foremost a geomorphological experiment: almost invisible from the outside, the building reveals itself through two cuts in the earth, two horizontal fissures that identify the terraces that have always characterized the landscape planted with vines. Beneath this garden roof are all of the factory's working and recreational spaces.
The garden roof was in this case an element strongly desired by the client, necessary to recover the area taken away from nature and reduce the actual consumption of land and allocate it to an educational vineyard cultivated with the typical Chianti variety, Sangiovese.
Danish firm Henning Larsen Architects has designed near Aarhus a museum with a green roof that rises from the sloping landscape to create a site for picnics in summer and sledding in winter. Positioned on a hillside in the suburb known as Skåde, the building is partially immersed in its rural site and features a roof that slopes steeper than the terrain to create an angular section.
The roof is covered with grass, moss and flowers and is interrupted by openings that form terraces, allowing natural light to enter the exhibition spaces arranged on three floors. Toward the top of the roof, a horizontal section juts out to form an observation point that offers views of the surrounding countryside and Aarhus Bay, from which the museum's outline is visible.
Continuing on the museum typology, Studio Marco Vermeulen of Rotterdam has renovated the Biesbosch Museum – a building with multi-pitch roofs – and added a new wing for contemporary art. The local history museum is located on a newly formed island in De Biesbosch National Park, a wetland area surrounded by willow forests southeast of Rotterdam. This context prompted the architects to cover the existing building with a layer of grasses and herbs, transforming it into a miniature landscape of hills, paths and streams.
The building's design aims to minimize energy consumption. Heat-resistant glass and a green roof help insulate the building throughout the year, while a biomass stove maintains the temperature on cooler days. On hot days, water is pumped through the same pipes to cool the building.
Speaking instead of start-ups and corporate realities, there are numerous entities that have been exploiting this architectural acreage as a growing site for some time now.
Brooklyn Grange, for example, is a 5.6-acre rooftop organic urban farm in New York City producing vegetables and honey for local restaurants, markets, and community-supported agriculture . The farm is located on three rooftops in Brooklyn and Queens. The first rooftop farm was established in 2010 on a 43,000-square-foot building straddling the Astoria and Long Island City areas. In contrast, the second location was built in 2012 atop the Brooklyn Navy Yard, and the third farm, established in 2019, is located at Liberty View in Sunset Park, Brooklyn.
Sou Fujimoto Architects renovated a hotel in Maebashi, Japan, by removing the interior floors of the original building and adding a grassy hill containing cabins.
An open passageway containing the hotel's main entrance also leads to an extension of the Heritage Tower on land that was formerly a terrace on a tributary of the Tone River. Named Green Tower, the extension is covered by a green hill that cancels out the one-story height difference between the front and rear streets of the site. The green slopes also refer to the concept of "mebuku," or "sprout," developed by Tanaka and the city of Maebashi to describe their vision of the city's ongoing redevelopment.
In the residential neighborhood of Putuo in northwest Shanghai, Heatherwick Studio proposed another challenge to the residential building typology by transforming it into a sculptural terraced mountain. In the project, the studio explored how this abandoned, once inaccessible industrial space could be opened to the city. Instead of a typical tower and podium, they looked for ways to bring the landscape through the site and create a new kind of urban topography in which the landscape is raised to form the volume of the buildings.
Slender columns support huge planters, making it appear as if green shoots are sprouting from the building. A mix of local shrubs, drooping plants, and deciduous and evergreen trees makes the appearance changeable throughout the year, just like a real mountain.
Located in the foothills of eastern Tainan, the Tainan City Government Agriculture Bureau Market was designed by MVRDV as a food supply center and a space for gathering and socializing. Built in collaboration with local firm LLJ Architects, the 12,331-square-meter market was topped by a curved green roof that forms “undulating hills” designed to blend into the surrounding landscape.
The building’s original design called for the roof to be used for crops, and MVRDV hopes that in the future it can be adapted for growing fruits and vegetables. Currently used as a park with colorful plants, further development of the roof could turn it into an educational farm teaching children about the food supply chain and how to grow products.