SINGAPORE (CNN) -- Singapore has long been considered a "garden city," a term coined in the 1960s by Lee Kuan Yew, the country's founding father and former prime minister. Since then, the island has embarked on extensive tree-planting programs and adopted so-called "biophilic" architecture, in which vegetation is often seen climbing up urban facades or emerging from skyscrapers.

A new six-storey university campus is the latest ode to nature in Singapore. Home to Nanyang Technological University's (NTU) business school, the gently curved design features sunlit atriums, outdoor study areas with lush backdrops, and elevators descending into tropical plant beds. Everything from railings to benches to door frames to space dividers (and even an adjoining bus stop) was built with wood.

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Also the beams and structural columns. In fact, the building is constructed almost entirely of solid wood, a new generation of engineered wood, layered and bonded with strong adhesives, which is pushing the boundaries of architecture. At 43,500 square meters, it is the largest wooden building in Asia by floor area.

Named Gaia, after the ancient Greek goddess of the Earth, the project opened in May and cost S$125 million ($93 million) to build. Its exposed wood structure has no cladding or paint, a design decision that celebrates natural materials and gives visitors the feeling of walking among trees.

According to the famous Japanese architect responsible for the project, Toyo Ito, that was precisely the goal. "In my designs I always try to create a connection with nature, like trees and water," he told CNN shortly after the building's groundbreaking ceremony. "The fact that they mention that it feels like entering a forest shows that my vision has been fulfilled."

Ito, awarded the Pritzker Prize (often referred to as the "Nobel" of architecture) in 2013, designed Gaia together with Singaporean design firm RSP. It has an auditorium for 190 people and a dozen classrooms, as well as research facilities, offices for teachers and large study terraces.


Apart from the toilets, ground floor slabs and exterior stairs, which were built with concrete (partly due to local regulations), the structure was made with wood felled from fir trees from Austria, Sweden and Finland. The wood was prefabricated into high-strength panels and beams in Europe before being shipped to Singapore.

Gaia will occupy 43,500 square meters and house the business school of Nanyang Technological University.
Credit: NTU Singapore

Global trend

In recent years, the number of large wooden structures built around the world has increased enormously. In some countries even skyscrapers are allowed, such as the Ascent in Milwaukee, Wisconsin, 25 stories and 86 meters high, which is the tallest wooden structure in the world.

Asian cities have been slower to adopt this trend than European and North American cities. Singapore's building regulations only allowed wooden architecture to rise up to 24 meters at the time Gaia was approved, although this height restriction has since been lifted. But Ito, 81, believes attitudes are "changing rapidly" in Asia: "Singapore is especially quick to make these things a reality."

The Building and Construction Authority of Singapore (BCA) claims that the use of wood en masse can reduce dust and noise on construction sites, while speeding up projects by up to 35%. Counterintuitively, proponents of wooden buildings claim they may also be safer and less prone to catastrophic collapses than steel-framed ones in the event of a fire (though not all experts agree).

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Proponents of solid or engineered wood point to the relatively slow and predictable rate at which the material burns. Gaia's designers also added a "sacrificial layer" of wood to the building's beams that, in the event of a fire, would char and protect the wood underneath.

Many of the purported advantages of solid wood are, however, environmental.

About 40% of global energy consumption is attributed to the construction and operation of buildings. But unlike concrete and steel, whose energy-intensive production is responsible for a significant portion of buildings' environmental footprint, trees absorb carbon dioxide throughout their lives.

If a tree is turned into solid wood, this embodied carbon is sequestered, rather than returned to the atmosphere. Studies suggest that one cubic meter of wood can store about a ton of carbon dioxide.

Wood also works as a natural insulator that, in warm places like Singapore, traps less heat than concrete (or reduces heat loss in colder climates). And while Gaia's designers say they have not calculated the emissions saved during the construction process, they claim that, in operation, the structure produces 2,500 metric tons less carbon dioxide than its concrete or steel equivalents, an annual saving equivalent to taking more than 550 vehicles off the road.

Singapore designated Gaia as a "zero energy" building. Credit: NTU Singapore

Passive cooling

Energy savings are not limited to materials. On the one hand, the exterior of the building has strategically located structures that cast shadow on the façade, helping to keep it cool.

Bursts of artificial air conditioning are also conspicuous by their absence.

Instead of mechanical fans, a feat in a country located less than 140 kilometers north of the equator, Gaia's air conditioning system relies on "passive cooling," which drives cold water through coils to cool the surrounding air. The breezy north-south orientation of the building favours natural ventilation by aligning with the direction of the prevailing winds in Singapore.

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The country's authorities designated Gaia as a "zero energy" building that (with the help of solar panels on the roof) produces as much energy as it consumes. To date, only 16 buildings in Singapore have achieved this distinction, and precisely half of them are owned by NTU, including a campus sports hall, also designed by Ito.

Throughout the design there are large terraces and atriums illuminated by the sun. Credit: NTU Singapore

At the inauguration of the building, the president of the university, Ho Teck Hua, used his speech to boast of having the "greenest campus in Singapore".

It remains to be seen what business school students think of their new home: classes don't start here until the new academic year in August. But there is growing evidence that the use of wood in architecture can have a positive effect on occupants' well-being, including reducing stress levels.

Ito, whose grandfather was a logger, says his design philosophy is still based on the comfort of the users of his buildings.

"I always keep comfort in mind," he explains. "If a building is comfortable, people will stay in it and visit it every day. I want to create an architecture that gives people a zest for life."

-- CNN's Mayumi Maruyama contributed to this report.