Bamboo: The 'green steel' of the 21st century
Today, sustainable architecture is not just a trend but an architectural style that has become a "revolution." Utilizing locally available natural material is a key element in any Green Architecture approach. Bamboo, which is an extremely fast-growing species of giant grass, grows abundantly, quickly and cheaply in Vietnam, where canes cost as little as a dollar each.
Vietnam has a tropical climate with high temperatures and humidity, advantageous for the growth of bamboo. Therefore, bamboo is an important forest resource of Vietnam. The annual consumption of bamboo in Vietnam is between 400 - 500M bamboo culms, used for various purposes. As an export crop, its value is well over 200M USD/year.
Building with Bamboo
Bamboo as a building material, with its high compressive strength and low weight, has been one of the most used building material in support of concrete. This is especially true in those locations where it is found in abundance. Bamboo is used for the construction of scaffolding, bridges, pavilions, outdoor structures and of course, houses.
There are essentially two types of bamboo used in VTN Architects’ bamboo projects — one uses bamboo that can bend to form curves and one that is straight. The bamboo that is bendable is locally called ‘Tam Vong’ (Latin name: Thyrsostachys oliveri Gamble), and the straight one is called ‘Luong’ (Latin name: Dendrocalamus barbatus).
Most bamboos have a low resistance to biological degrading organisms and need specialized bamboo preservation techniques. A wide range of treatment methods are known to improve its durability. Without any protective treatment, most bamboo species have an average natural durability of less than 2 years. Stored under cover, untreated bamboo may last 4-7 years. Untreated bamboo, just like almost any other wood, has a high chance of being attacked by insects. Bamboo insect infestation occurs due to the presence of starch and other carbohydrates. Insects obtain their food supply from the bamboo and degrade it.
At VTN Architects, we put the bamboo into the water to speed up the aging process. So when bamboo rots, its chemical make-up changes so that insects like beetles will no longer eat the toughened bamboo. Treating bamboo in this way is the traditional knowledge of Vietnamese craftspeople, because of all of the baskets, chopsticks, and many other products they make from bamboo. Many villagers put bamboo into the water and they then use it after three to six months. We treat bamboo based on their knowledge but we add one more step—smoking. When we remove bamboo from the water the smell is not nice and the skin is very dry as the oil escapes. So we smoke it for two weeks to coat the outside and dry it out, that way we can replace the oil lost. Bamboo that is treated with this traditional Vietnamese method can protect the wood for 30 to 50 years.
When we smoke the bamboo we burn rice husks for the smoking, which contains oil. In this process, the smoke and the oil from the husks automatically bind with the bamboo. After smoking, we polish the outside of the bamboo to make it shiny. The combination of putting bamboo in water and then smoking it makes it last even longer.
One disadvantage to using bamboo in our designs and construction is the irregular shapes and evenness of the bamboo material. Another issue is the expertise and skill required to work with the material. When asked about these difficulties in a past interview, Vo Trong Nghia, VTN Architects principal architect and founder said, “Bamboo has own characters, which result in unique structures and spaces. It is not easy to create beautiful spaces by using bamboo, because it is uneven material. We try to control the accuracy of the construction by applying unit-frame prefabrication. The other issue of bamboo construction, compared to steel or concrete structure, is difficulty to choose an appropriate contractor. There is almost no contractor with experience of bamboo construction. So, in order to realize the space as envisioned, it is essential for us to educate workers and build the construction together.”
It is for this reason that VTN Architects has cultivated several expert bamboo construction teams and keeps them very busy in Vietnam and in other countries like China where big projects are always underway. Many of the construction workers are rice farmers that function in dual roles as agriculture workers and bamboo construction workers. They rotate in and out of the construction teams as they go back to the homes to attend their rice farms.
The 'green steel' of the 21st Century
Despite the challenges, Vo Trong Nghia says, "I think bamboo and laminated bamboo will replace other materials and become the 'green steel' of the 21st century. I hope many architects realize the potential of the material and build with bamboo more and more."
See more about Huong An Vien Welcoming House.
See more bamboo architecture projects.