• Parkroyal on Pickering in Singapore (2007) is a mix of hotel, offices, and apartments. The program elements are linked by generously sized planted common areas. Photo by Patrick Bingham-Hall.

Garden City|Mega City
Austin Central Library

From February 27 through April 15, 2018, the Austin Public Library in collaboration with the Austin Parks Foundation showed “Garden City|Mega City,” an exhibit featuring 16 projects by Singaporean architecture firm WOHA. The gallery was kept dim, apart from WOHA’s inwardly lit models covered in greenery, which led visitors through the space like breadcrumbs. It felt like a car dealership in a rainforest. Porsche, in fact, sponsored the show.

Garden City|Mega City first surfaced in 2016 at The Skyscraper Museum in New York City. In 2017, it moved to the Museum of the City of Mexico. While showing in Mexico City, an Austin real estate professional happened to see the exhibit. Later, he had a chance meeting with John Patrick of Above The Fold, WOHA’s PR rep in the U.S. Together, they raised the funds to bring the exhibit, and WOHA’s environmental philosophy, to Austin. The result was a presentation of the firm’s brand of ecologically integrated architecture, presented with the hope that WOHA might be hired to tailor a building to Austin, or that their research and designs might inspire local designers.

WOHA was founded in 1994 with sustainability as a guiding principle. Their ecological priorities are clear even in their early private residential work. Over the past 20 years, the firm has shifted focus from the private to the public domain, hoping to broaden the scope their impact might have. Calling themselves “humanists,” WOHA designs with occupants in mind, connecting them to nature for their physical and emotional benefit. By thinking of their buildings as towns within a larger city — “micro-urbanisms” — WOHA streamlined a few formal techniques to meet their environmentally humanist goals: layering cities, planting cities, and breathing cities.

Parkroyal on Pickering in Singapore (2007) acts like a layered city, with shared vertical sky gardens every four floors. WOHA calls this approach “High-Density, High-Amenity” because it allows a building with a condensed footprint to provide natural amenities to its urban occupants on all floors. The architects also designed Parkroyal as a “planting city,” with external corridors leading hotel guests past a screen of green vines enveloping the rear facade on the way to their rooms. Parkroyal is a combination of hotel and office spaces, designed with a steel frame and glass envelope to fit in Singapore’s business district while also juxtaposing the otherwise-orthogonal design with moments of topographically inspired form in the sky gardens. Shared outdoor space is volumetrically removed for the ground floor, and a sky garden on the roof provides a green gathering space. The tension between the natural and built forms is intended to heighten the occupants’ perception of both, allowing the building to read like an office, while also implying that life is lived differently inside.

WOHA has also designed public housing with these principles — including Skyville@Dawson (2007), another Singapore project. In plan, the building has a triple-diamond shape with openings at its corners allowing the breeze to pass through. Skyville was designed to be a “breathing city,” with vertical breezeway atria making up the core of each of its three towers, sending air and sunlight even to the inward-facing units. The vertical atria are interrupted every 11 floors with community spaces and sky gardens, making Skyville another example of “High-Density, High-Amenity” space. Though the expectations for public housing are usually low, WOHA designed with the same consciousness of the elements expected of them, to create environmentally sensitive housing with dignity.

Oasia Hotel Downtown (2011) in Singapore was designed to be a “breathing city,” a “planting city,” and a “layered city” all at once. Three volumetrically removed “breezeway atria” on the 12th, 21st, and 27th floors are shared by guests as cool gathering spaces, with pools and seating. The whole volume is enveloped by a planted vertical “screen of green” made up of perforated red and orange panels that wrap the exterior and support an additional envelope of plant life.

Vertical green walls like Oasia’s are a popular international solution to the desertification of urban environments. When executed thoughtfully, they can rebuild habitat, sequester carbon output, act as pervious cover in rain, and even help maintain a site’s original biome. However, if a building like Oasia were to be built without any modification for the Texas climate, the imported plant life would take more energy and provide less ecological benefit than it may be worth.

Daniel Woodroffe, founding principal at Austin-based dwg. landscape architects, argues that most vertical urban greenery requires intensive maintenance and ultimately is more of a social than an environmental benefit. “The truth of the matter is that an atrium, terrace, or roof terrace — or anything green on the structure — is inherently very maintenance-intensive,” Woodroffe says. “It’s really about the intangible connection you and I would have in that space, being closer to landscape, and the feel-good psychological impact that has on a human being’s health and vitality.”

There are two camps when it comes to updating relationships between the built and natural environments: those making buildings independently sustainable, and those making the fabric between them sustainable. Woodroffe thinks WOHA belongs to the former camp, as they tend to inwardly design natural elements — as with the atria at Oasia and Skyville — and consider each building’s environmental impact microcosmically rather than derivatively. These camps aren’t diametrically opposed; if anything, they work better together and, depending on the city, one approach or the other might make more sense.

Woodroffe thinks the interstitial space in downtown Austin requires some work from the latter camp, for social reasons. Austin’s downtown buildings don’t promote community, outside of small retail spaces and gaping program-less lobbies at their ground floors. dwg.’s latest project, Fareground, is part of a collaboration in response to the lack of connection that buildings on Congress Avenue have with their site condition. What used to be the most lively street in all of Texas, today is mostly filled with bank headquarters. Fareground introduced Austin’s first food hall and an outdoor courtyard to 111 Congress Avenue, reinventing the building to accommodate life on the street level.

Thoughtfully developing space between buildings is a strategy as important as that of the former camp. Whether it leads to new pocket parks, private courtyards, or green roofs, each outdoor space has potential to be utilized environmentally: to combat carbon in the atmosphere, promote biodiversity, decrease runoff, and address many other environmental concerns.

To assess the environmental success of its designs, WOHA developed its own rating system of various social and ecological metrics for sustainability. For example, the firm’s “green-plot ratio” and “community plot ratio” measure the balance between site area and landscaped surface area or community space area. WOHA also measures its projects by “self-sufficiency,” a development’s capacity to provide its own energy, food, and water; the “ecosystem contribution index,” the degree to which a development supplements its city’s ecosystem; and the “civic generosity index,” which defines the extent to which the building encourages public life in the city.

WOHA’s Oasia Hotel Downtown has the highest-ever “green plot ratio,” at 1,110 percent: The green envelope exceeds the site’s square footage by more than 10 times. The result is aesthetically satisfying, but according to WOHA’s city ratings it does more than just look sustainable: It is self-sufficient for 60 percent of its water, and has an “ecosystem contribution index” of 60 percent, meaning it provides vertically and horizontally interconnected habitats with birds and insects in mind.

At first glance, this unique self-accountability kind of looks like the firm is patting itself on the back for niche standards they set themselves. John Hart Asher, landscape designer at the Lady Bird Johnson Wildflower Center, however, said that’s how environmental progress is best achieved. “We have to start out with clearly stated goals for the project,” Asher says. “The great thing with ecological work is that they don’t necessarily have to do every sort of ecoservice, but if you do one well, you’ll get a few others.”

If a project restores site soil, for example, or more diverse plant communities are introduced, Asher says, the site could become more habitable, promote carbon sequestration, or even help mitigate heat island effect. Performing exceptionally in one ecological facet will benefit the whole system, because the environment operates as a delicately wound whole, not as a collection of different categories.

WOHA’s rating systems represent its excellent performance in a few of these ecological facets. “Like the ‘green plot ratio,’” Asher says. “I think that’s a great generative start, but just because you have a green area doesn’t mean it’s functioning well.”

Greenery doesn’t always entail sustainability. Depending on a site’s climatic and ecological conditions, plant life might be important for flood or erosion prevention, shade, food, habitat, or carbon sequestration. For example, a building with non-native plant life might use tons of water to keep its plants alive, while native plants would require less energy and resources.

Singapore is classified as a tropical wet climate, but Central Texas is more of a temperate grassland with some diminishing Blackland Prairie ecosystems. While WOHA’s techniques couldn’t be directly copied and pasted from Singapore, they could be translated for local climates.

“The Blackland Prairie ecosystem is one of the most endangered; there’s less than one percent in existence,” Asher says. “If people started using [locally planted] green roofs, the Blackland Prairie could start to thrive again in the dense urban cores, helping control runoff and flash flooding.”

Asher thinks urban design with a local environmental mindset can change the relationship between the built and natural environments entirely. “We could suddenly have larger and larger prairie areas in our city, and that would be hugely impactful and really start a paradigm shift in the conception of city as antagonist,” Asher says. “That’s really exciting to me.”

WOHA’s environmental logic, when considered with site sensitivity, could make the world a better and healthier place to live, one building at a time — shifting the relationship between the natural and built worlds from parasitic to symbiotic.

Hannah K. George is an architecture and Plan II student at The University of Texas at Austin.

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