From Green Roofing to Vertical Farming

Green roofs, eco-roofs, vegetated roofs, or living roofs, whatever you want to call them are becoming trendy commercial building additions in many parts of the world.

This photo of a re-creation of Viking houses in Newfoundland illustrates the use of grass as a building feature that helped maintain a comfortable living environment year-round. Plus it was readily available and cheap. But this was on buildings many centuries ago.

Today, we have commercial buildings such as this one in Fukuoka, Japan. This building, designed by architects Emilio Ambasz & Associates, houses offices, retail space, a 2,000 seat theater and a museum. Home to 35,000 plants, the ‘living’ roof greatly reduces the amount of energy required to heat and cool the building occupants. For more views of this building click here.

The Hundertwasser house (Forest Spiral), built in Darmstadt, Austria between 1998 and 2000 was designed by Friedensreich Hundertwasser, the famous Austrian architect and painter, who was widely renowned for his revolutionary, colorful architectural designs which incorporate irregular, organic forms, e.g. and onion-shaped domes. The structure houses 105 apartments that wraps around a landscaped courtyard with a running stream.

Canada’s largest green roof, Vancouver’s Convention and Exhibition Center, is currently under construction. It is expected to be completed in 2009 and will host the international media and broadcast center in the 2010 Winter Olympics. At a cost of over 850 million dollars the cost of this mammoth undertaking is being viewed by some Vancouver residents as excessive saying the money should, instead, go towards housing and feeding the poor.

One of the world’s largest green roof is in the USA, at Ford Motor Company's River Rouge Plant, Dearborn, Michigan, where 42,000 square meters (454,000 ft²) of assembly plant roofs are covered with sedum and other plants. Other well-known American examples include Chicago’s City Hall and the Gap headquarters in San Bruno, CA. Recently, the American Society of Landscape Architects retrofitted their existing headquarters building in Washington, D.C. with a green roof designed by landscape architect Michael Van Valkenburgh. The cities of Chicago, Atlanta and Portland, Ore. also boast numerous green roofs.

This photo of the green roof Mountain Equipment Co-op in Toronto Canada is a prime example of mixing beauty with functionality to city rooftops.

Switzerland has one of Europe's oldest green roofs, created in 1914 at the Moos lake water-treatment plant, Wallishofen, Zürich. Its filter-tanks have 30,000 square meters (320,000 ft²) of flat concrete roofs. To keep the interior cool and prevent bacterial growth in the filtration beds, a drainage layer of gravel and a 15 cm (6 in) layer of soil was spread over the roofs, which had been waterproofed with asphalt. A meadow developed from seeds already present in the soil; it is now a haven for many plant species, some of which are now otherwise extinct in the district, most notably 6,000 Orchis morio (green-winged orchid). More recent Swiss examples can be found at Klinikum 1 and Klinikum 2, the Cantonal Hospitals of Basel, and the Sihlpost platform at Zürich's main railway station.

Green roofing represents the next step in the growing evolution for more sustainable struwctures. Commercial structures that can collect and reuse rainwater to better manage stormwater runoff can avoid the need for expensive underground sand filters. They also combat the urban heat island effect of traditional building materials that soak up the sun’s radiation and re-emit it as heat, making cities at least 4 degrees Celsius (7 °F) hotter than surrounding areas. Here, Atlanta Georgia’s City Hall is covered with vegetation and soil creating energy savings as well as aesthetic benefits.

Rooftop water purification is also being implemented in green roofs. These forms of green roofs can actually have ponds built onto the rooftops. They are built either from a simple substrate (as being done in Dongtan China) or with plant-based ponds (as being done by WaterWorks UK Grow System).

Green roofs also provide habitat for insects, birds, bees and butterflies. Rooftop greenery complements wild areas by providing "stepping stones" for songbirds, migratory birds and other wildlife facing shortages of natural habitat.

As our natural habitat is replaced by urban development with its impenetrable asphalt and concrete surfaces, wildlife is being relentlessly pushed into smaller habitats. This results in food and shelter becoming less abundant and therefore their numbers are dwindling. Reintroducing green spaces into the environment has several other benefits for both humans and wildlife. The already mentioned benefits of stormwater management, energy conservation, mitigation of the urban heat island effect, are coupled with increased longevity of roofing membranes, as well as providing a more aesthetically pleasing environment in which to work and live. The construction and maintenance of green roofs provide business opportunities for nurseries, landscape contractors, irrigation specialists, and other green industry members while addressing the issues of environmental stewardship.

The next evolution in green roofs is rooftop farming, or sky farming. If you can grow grass and flowers on the roof, why not grow food?

Traditional indoor gardening facilities (factory greenhouses) designed to produce what used to be considered seasonal food crops year-round have sprung up in Japan, Scandinavia, New Zealand, the United States, and Canada. These are all single-story buildings. The time for a new direction in indoor farming has come. Vertical farming, stacking multiple layers of farm acreage into towers to provide fresh food crops to urbanites which simultaneously cuts down on transportation costs of getting the produce to market.

With earth’s population approaching the apex beyond which we can no longer produce enough food to sustain it, vertical farming is a theoretical construct whose time has come. It is predicted that food prices will increase dramatically over the next year due to food shortages. Already we have seen the effect of higher food prices artificially created by the misguided reapportioning of food crops to biofuel production. The spike in oil prices has pushed up fertilizer prices, as well as the cost of trucking food from farms to local markets and shipping it abroad. Climate change seriously disrupt harvests by freak weather, including prolonged droughts in Australia and southern Africa, floods in West Africa, and this past winter's deep frost in China and record-breaking warmth in northern Europe.

Vertical farming can address these issues and others. One self-sustaining vertical farm taking up one square city block and rising up 30 stories could provide enough nutrition to feed 10,000 people, utilizing currently technology. The building could also produce a net output of clean water and energy. Estimates show that 150 such buildings would be required to feed the entire city of New York for a year. However, we still need research in many areas to produce the greater yield that is going to be required to make these structures financially viable. According to experts, additional research in hydrobiology, engineering, industrial microbiology, plant and animal genetics, architecture and design, public health, waste management, physics, and urban planning, are needed to make this increase possible.

Architects have designed some very promising structures to help meet the expected need. Here Daekwon Park designed what is called a Symbiotic Interlock system of modular, prefabricated units that are attached to the outside of existing highrise buildings. The system of stackable modules add an extra layer of infrastructure to existing buildings via sky docks and bridges, vertical gardens, cultural spaces, and energy producing wind turbines. It addresses some of the shortcomings of green roofs by internalizing green environments within its biomorphic structure while contributing functionality, energy, and food.

Architect Pierre Sartoux of Atelier SOA designed this vertical farming skyscraper. A light-shading skin wraps around the structure and opens to admit sunlight at particular locations for various functional (and aesthetic) purposes. The building’s air, heating and cooling systems are wind-driven and circulate oxygen and carbon dioxide between growing and living spaces. The simple but reinforced structure is designed to handle additional dead loads from the weight of growing floors and also serve to make the entire building more durable (and thus sustainable).

In a different direction we go below the busy streets of Tokyo, just steps from the subway system, where you can find Pasona O2, an indoor urban farm where vegetables, rice, flowers and herbs flourish under fluorescent lights and LEDs in an environment that is almost entirely chemical-free. In a basement that was once a bank-vault, plants are cultivated and nourished hydroponically using nutrient-enhanced water instead of natural soil. Temperature, humidity, and carbon dioxide levels are all controlled by computers. This kind of tank-farming makes it possible to grow plants rapidly, all year round, by maintaining an optimal balance of nutrients.

Shanghai has also moved its greenery below ground. Shu Yu, deputy director of the Shanghai Urban Underground Space Development Institute, has revealed that local architects are working on developing China’s first underground park. Architects will landscape one of Shanghai’s existing underground shopping malls or pedestrian walkthroughs and complete the park in three years. The park is set to cover hundreds of square meters and eventually look like a small forest with winding streams. Can farming be far behind?

Moving onto the waterways running through cities is another adventure in farming. The Science Barge is a sustainable urban farm designed by New York Sun Works, a Manhattan-based environmental nonprofit organization. Situated atop a floating ‘barge’ greenhouse powered by solar, wind and biofuels, and irrigated by rainwater and purified river water, the farm grows food in the city with no carbon emissions, no net water consumption, and no waste stream. The vegetables grown on the Science Barge require seven times less land and four times less water than traditional field crops. The center also uses a method called ‘recirculating greenhouse hydroponics’ to grow tomatoes, lettuce, cucumbers, and peppers. No soil or pumped in water is utilized in this cultivation process.

Clearly ingenuity is flowing throughout our society. Hopefully, these new forms of high-tech, urban farming will encourage a new generation of farmers.

Further reading and study:

New York Magazine: Sky Farming

National Roofing Contractors Association has published a manual providing in-depth information about green roof projects.

City Farmer News: Guide to Setting up Your Own Edible Rooftop Garden

Urban Agriculture Notes