Commissioned to design a green-oriented café in Binhduong, a newly developed industrial area next to Ho Chi Minh City, Vo Trong Nghia Architects got a chance to put their previous experiments of wind and water cooling system into practice with the bamboo expression.It was named wNw (wind and water) Cafe in the end.
wNw Cafe is currently located in a rampant tropical landscape as a consequence of VTN's efforts in the early stage. The landscape, together with the artificial lake enclosing the building, plays an important role in realizing a comfortable environment in the cafe space. The roof of the building was made of a combination of bamboos and steel tensile members, providing voluminous space of maximum 12-metre width without columns. Its V-shape was generated according to CFD analysis, aiming at maximizing the wind flowing into the building.
wNw Cafe consists of thousands of bamboos with minimum usage of steel component. With traditional processing methods of bamboos such as soaking and smoking out, bamboos demonstrate its outstanding characteristics of aesthetic, durability, ecology and cost efficiency as housing materials. Bamboo not only has been the traditional building material in Vietnam but also is the green material of the 21st century due to its excellent CO2 absorbability and higher rebirth ability of bamboo forest in comparison with other tropical forests. It not only is a decorative material but also plays an important role as main structure. Bamboo material has its own attributes such as: small and uneven dimension, high durability to bend. As for those special characteristics, VTN used bamboos in the curving structure to maximize its potential and cultivate its grace of curvature, which is totally different from other wood materials. With the limitation of length and dimensions of the material, bamboo structure becomes the composition of small pieces. As a consequence, numerous joints are unavoidable and its details become the essence in the bamboo structure. It is commonly to use the metal joint; however, the organic characteristic and cost advantage for bamboo structure is lost with too many metal joints used.
Therefore, VTN used their own way - tying rope and using bamboo wedges - to make joint as the sleek transition of the body. In spite of such low technologies as used for wNw Cafe, the company's aim was not merely to build folk handcrafts in local areas but to create architecture in this age. It was essential for the company to develop a system of production and construction of bamboo architecture. If the whole structure is divided into several frame-units, the accurate structure under appropriate cost control is to be realized. The assembling of these frame-units should bring more flexibility in transportation for bamboo structure.
The idea of the assembly system was carried out in the next project. wNw Bar was constructed next to wNw Cafe and it was the first project by the company with pure bamboo structure. In contrast to the open, linear space of wNw Cafe, wNw Bar was designed as a closed dome. As a result, the project site ended in having two types of building with different ways of making harmony with the nature; the one melts into the nature (wNw Cafe), the other stands out from the nature (wNw Bar).
wNw Bar is also located in an artificial lake and it uses the natural wind and the cool water of the lake as the main source of energy to make the natural air-ventilation. A 1.5m-diameter skylight on the centre of the roof is served as the ventilator to circulate the air to help extracting the heat from inside of the bar. A structural bamboo arch system was designed for this dome with the dimension of 10-meter high and spanning 15-meter across. The main frame is consisted of 48 prefabricated units and each of the unit is composed of several bamboo elements. Each of wNw Cafe and wNw Bar was built by local workers in duration of 3 months. The energy saving during the construction as well as in the operation has made this bar an integral part of the nature, harmony with the nature and return to the nature.
Vietnam is a developing country facing environmental and energy crises. In such a situation, Vietnamese people has been transformed themselves from mass-consumption-oriented into energy-saving-oriented as with in other countries. By using natural materials and energy, wNw Cafe and Bar matches this new tendency and therefore it may have a great impact on the society.
Bamboo has been traditional building material in Vietnam simply because that it is easy to get and to transport; the country has a lot of bamboo forests in its land and the weight of a bamboo is extremely small. However, it hasn't been easy material to handle in a unique expression because of its small and uneven dimension. The company's endeavor focused on the way to create the expression of contemporary architecture with this traditional material in order to satisfy both conventional and innovative sense of the local community. The goal was to realize intimate and stimulative space with low budget. Therefore, both traditional and contemporary methods of handling bamboos were adopted in the projects.
The bamboo work of wNw Cafe and Bar mainly consists of the following three methods.
1. SOAKING AND SMOKING OUT (traditional) Soaking bamboos in mud for several months and then smoking them out are the traditional method to make the bamboos capable of withstanding decay for a long time with an effect of anticorrosion and insect proofing.
2. TYING ROPE AND USING BAMBOO WEDGES (traditional) No metal nail was used for the project. Using metal nails loses the cost advantage of bamboo architecture because of its numerous joints. Instead of them, wNw Cafe and Bar has joints with tying rope and bamboo wedges to realize the sleek transition of the bamboo structure.
3. ASSEMBLY SYSTEM (contemporary) A broad application of the bamboo structure to various types of buildings cannot be realized without assembly system. Gathering some bamboos into one unit reduces the disadvantage of uneven dimension of bamboos and enables easy transportation, so that it has the great applicability with low cost, short construction period and high accuracy of the construction.
One of the most remarkable features of bamboo is its fast growth. Some species of bamboo take only a few years for the harvest. Consequently, applying bamboos as the main material reduces construction cost as well as plays an important role in a sustainable aspect. In addition, neither wNw Cafe nor wNw Bar are equipped with air conditioner. The roof shape of each buildings, a V-shape (wNw Cafe) and a dome shape (wNw Bar), were designed to enhance the air current under the roofs in combination with the artificial lakes surrounding the buildings. In comparison with an air-conditioned cafe, wNw Cafe has consumed only 10% of electricity.