Is building with bamboo the housing solution for tropical cities?
QUITO, Ecuador — The two-story bamboo house on display in Quito’s El Ejido Park this week is shining a spotlight on bamboo as a source of cheap, renewable building material for cities.
“Bamboo remains an untapped development resource to help build affordable and sustainable housing for developing nations,” said Oliver Frith with the International Network for Bamboo and Rattan (INBAR), a body that works with governments to develop research and expertise on the two building materials.
An indigenous building material common in the tropics, bamboo is often used to build huts in Asia and even in Latin America, especially in coastal communities. Bamboo has a tensile strength comparable with steel and concrete, without requiring extractive methods for production. It also grows fast, and can easily be replenished in about five years, said Frith.
Bamboo construction recently got a test when Ecuador was rocked by a strong earthquake in April 2016. According to research from INBAR, most of the estimated 2 million houses in the quake zone made with bamboo were able to “withstand the impact or sustain partial damage only,” Frith said.
This resulted in a national policy in Ecuador that includes bamboo in a list of sustainable building materials in the national construction code as well as future housing policies. Families whose homes were destroyed by the quake and want to rebuild using bamboo materials can take advantage of a government housing subsidy worth US$10,000, according to Frith.
The bamboo house in El Ejido Park is situated across the street from the main venue of the U. N.’s Habitat III summit on cities taking place here this week. It’s part of an exhibition of real-world urban innovations scattered across Quito called the Habitat III Village.
Outside the bamboo house.
(Habitat III Secretariat)
Just about everything in the house is made of bamboo: the six-foot columns out front, the boards that form the walls and floors, and the furnishings. The products were sourced from a local network of small growers. The house has a loft and two flights of bamboo staircases on each side of the main hall. Despite the afternoon heat, the building remains cool inside because the the building material can “breathe” and so does not trap heat.
The price tag of the house is US$15,000. Depending on how well such houses are designed and maintained, they should last at least 30 years, Frith said.
In the Philippines, research institutions have been actively promoting bamboo as a building material for resilient housing, especially for those who displaced by the country’s frequent typhoons.
“Bamboo can help us build green, resilient housing,” said architect Christopher de la Cruz, founder of the Philippine Green Building Council. “There is a common notion that for a building to be green, it has to be expensive. Bamboo disproves that in terms of having durability that is relatively comparable to modern construction materials.”
Another benefit of bamboo lies in its ability to prevent erosion and reduce flood risks. Studies show that a clump of bamboo can hold 6 cubic meters (212 cubic feet) of soil, and its extensive root system makes it an effective tool to prevent erosion and maintain slopes. In Rwanda, for example, there is a National Bamboo Policy that mandates the planting of bamboo to prevent erosion in river banks and lake shores.
During a panel discussion at Habitat III, Sally Lee, the mayor of Sorsogon in the Philippines, noted that her city’s efforts on mangrove and bamboo reforestation has helped them weather major floods and even storm surges in the coastal part of the city.
“The bamboo is durable in terms of preventing coastal erosion and flooding,” Lee said. “Also, it doubles as a source of sustainable livelihood for many in my city.”
Despite its many advantages, bamboo still has not breached the global design market. Part of the challenge is the need to build the value chain for production. Most of the farmers involved have smaller tracts of land and must form groups to be able to benefit from economies of scale. In addition to planting areas, production of prefabricated bamboo construction materials requires storage for drying freshly harvested plants and a treatment area for spraying chemicals that make the bamboo more durable and seal out moisture.
Worldwide, the market for bamboo and rattan was about US$1.9 billion in 2012. This is expected to increase as more technology solutions such as chemically treated or engineered bamboo makes it a more durable material for applications that would traditionally call for timber.
At a Habitat III talk, Pritzker Prize winning architect Alejandro Aravena, who curated this year’s Venice Architecture Biennale, advocated for the use of humble materials readily available to the world’s urban poor. “Nobody is lobbying for bamboo or mud,” he said. “I tried to bring as much of it as I could to the Biennale.”
The Biennale, which closes in November, includes bamboo structures by Colombian architect Simón Veléz and Americans Doug and Mike Starn. Aravena explained the irony that such structures can only serve as art exhibits in Venice because they wouldn’t pass muster with European Union building codes.
Government support is part of the solution, said de la Cruz. In the Philippines, a presidential decree requires at least a quarter of school furniture to be made from bamboo. But educating the public about bamboo’s potential role in building sustainable cities is also key. Which is why the bamboo house is on display at Habitat III.
“There is a need to create more awareness about the many benefits of bamboo, and one way of doing that is showcasing its use like in this bamboo house,” Frith said. “People can go inside and see the structure so they can decide from themselves.”