Meeting with Olivier Betting, head of Asali Bali, one of the main companies based in Bali and specialized in bamboo construction engineering in Indonesia and abroad.
As a steel structural engineer, how did you come to use only bamboo to construct buildings?
It is a personal journey, also linked to the impact of my original profession. Metal and concrete require a lot of energy, it also contributes a lot to greenhouse gas emissions. Not to mention the extraction of sand which also devastates rivers and beaches. Bamboo has phenomenal mechanical qualities to the point that the span reached 45 meters for a bridge in Columbia and 35 meters for International Bamboo and Rattan Organization’s building in China. If we take the necessary precautions, bamboo is solid and durable, and in addition it allows architectural audacity at low cost. From my carpenter grandfather and my mother, a wood structure teacher, I was made aware of the preservation of our resources from an early age as well as the alternative solutions that we can develop, or rather reinvent in a modern context.
So, tell us the limits of bamboo and the precautions it requires for its implementation
Being an organic material, bamboo is subject to humidity, insects and UV rays. It seems prohibitive but in fact, we can live with it provided we treat it well and arrange it. Against insects (and in particular Powderpost Beetle more than termites), it is treated with a natural salt, borax borix, for 3 days. Against the humidity favorable to the development of fungi, you must make sure to dry your bamboo until the humidity level drops below 20%. We usually say that bamboo needs boots and hat, which means that it must not be in contact with the ground to avoid water and splashes of humidity associated with washing soils. Bamboo is naturally protected by a layer of silica which is sensitive to UV sunlight, so avoid exposing it to direct, overhead sunlight. This is why in general we overhang the roofs so that the sunlight does not penetrate more than 45° into the structure.
How durable is a bamboo structure? Do you guarantee it for at least 10 years?
Yes, we guarantee it for 10 years provided that our customers take out a maintenance contract equivalent to 10% of the construction price (1%/year). Out of 1.000 treated bamboos, there are on average 3 which contain insects and which should be treated or replaced. It is a risk, we do not hide it. It is advisable to check visually (twice a year) that the structure is aging well, this can happen faster than on a metal or concrete structure if you do not take care of it. However, a metal structure exposed to rust or a concrete wall exposed to humidity can also be subjected to the natural elements until it breaks.
Have all your customers embraced the trend of bamboo or do they simply see it as a financial or even purely aesthetic interest?
I think it’s the aesthetic that takes precedence, no need to hide it in the age of social networks. Bali has become the showcase for bamboo construction in the world with dozens of buildings, each more breathtaking than the next. Then, I would say that it is the financial argument. For example, we are in talks with a Turkish company investing in the Maldives which prefers to build with bamboo from Bali rather than wood from Russia, it is much faster to implement and it offers more possibilities in matter of architecture. For our part, we charge around 3 million IDR (200 USD) per square meter for the construction in Bali including bamboo structure and roofing (Foundations, MEP… not included) it is very competitive. The business plans are calculated over 20 years, there is real profitability with bamboo.
So precisely, why has Bali become the world reference in bamboo?
It was Linda Garland in the 80s who gave the impetus with her Environmental Bamboo Foundation. The torch was taken up by John Hardy with the construction of the Green School in the 2000s. During the last World Bamboo Congress held in Vietnam, it was noted that it is in Bali that we find such an emulation, people are very envious of the level of finishing and the architectural innovations. Whether in Colombia, the Philippines, Thailand and even Vietnam, companies specializing in bamboo are involved in a fairly limited range of action.
But, it is more than important to underline that all this is based on an artisanal know-how still present in Bali, in particular in Belega in the Gianyar region where our company has been established since 2009. We build a lot of bamboo in Bali always and there is therefore a workforce that perpetuates a very qualified traditional know-how to implement the bamboo but also to cut and treat it. As often in Bali, it is the encounter of foreigners with highly qualified Balinese craftsmen that makes it possible to achieve this level of excellence and this is the main reason for the success of this bamboo construction sector.
Does Bali produce enough bamboo for the needs of this booming industry?
Unlike Java or China where there are plantations for the bamboo industry, the bamboo we use comes from small producers and forests, thus avoiding monoculture land. Bamboo being a grass, as soon as a cane is cut, it will grow back (provided that the roots are not cut). Bamboo grows very quickly, 40 to 60 cm per day and can reach 20 to 30m between 3 and 6 months But it is only after 3 years and sometimes 5 years that it can be cut, we must wait until its walls have thickened (9% of the diameter) It is cut during the new moon and dry season. It is therefore understandable why it is a first-rate ecological product, not to mention that it sequesters carbon even better than trees (30% more than a deciduous forest) and that its end of life does not pose a recycling problem.
What are the different products made from bamboo?
First of all bamboo poles which measure up to 12m long with a maximum diameter of 15cm, pieces of choice for making beautiful structures. Then, inspired by all the local craft techniques, we cut it into slices, lengthwise, in all directions. It is gathered in bundles to give these organic shapes to the frames. We even make tiles with 7 layers of bamboo/m.
Why are there mainly yoga shalas, hotel lobbies, restaurants, bungalows and so little individual bamboo housing?
Although there is a growing demand for individual housing, we have not yet worked on turnkey solutions for individuals. We specialize in bamboo structure only. Our goal is to bring our knowledge of large-scale bamboo buildings in order to professionalize practices and change the perception around this material such as the lobby that we are building in Sumatera which will be the largest building in bamboo in the world ever realized (3122m² of roof, opening planned for new year 2023).
Why all these mock-ups in your workshop?
We are one of the few companies in the world to specialize in bamboo with 4 structural engineers working permanently but you never see the rendering as well as with a mock-up. We generally start with an intention mock-up to imagine a form that sticks to the desires of the client, to the topology of the land and the project. And then, once the calculations are finished, we will produce a mock-up on a scale of 1/50th in general (2cm=1m) which includes exactly the number of bamboos that fit into the construction. This is essential because sometimes the 3D design does not render certain curves precisely enough, it helps us a lot to visualize the project with the client as well as to communicate with the teams on site.
What is your dream for the future?
Building a bamboo airport would change people’s perception of this material and contribute to modifying mentalities on ecological and sustainable solutions, we already have the plans [smiles]. The next step is to set up other entities around the world to promote Balinese know-how and bring our expertise to use local resources in each environment.