BAAN DOI guest houses
In Thailand's Chiang Rai province, two of the four guest houses are being built for the NGO Baan Doi as part of their agricultural centre. Near the border town of Mae Sai, the NGO runs a home for 20 orphans and runs projects for underprivileged children in the region.
Over the past few years, our partner NGO Baan Doi has been able to produce organic food for their own consumption and to teach children and other interested people in the area how to farm in harmony with nature. In this context, the four guesthouses planned will not only provide accommodation for visitors to the agricultural centre, but also a source of income for the NGO.
After the completion of the family house in early 2022, we implemented the next phase of the project. During a three-month practical semester, BASEhabitat postgraduate students built a guest house with a private bathroom and a terrace with an outdoor kitchen, under the supervision of the construction manager Florian Fend.
The BASEhabitat postgraduate students developed the design in Linz and spent three months on site building an initial prototype. Over the course of two weeks, the students produced 2500 adobe blocks using a mixture of local earth, rice husks and sand. A local Thai construction company was involved in the building process and supported the team.
During the construction, the students were able to experience all stages of the bamboo manufacturing process: from harvesting, to treatment, to cutting and finally to the assembly of the roof structure. After erecting the bamboo columns, terrace and roof structure, they started with the adobe masonry walls incorporating the windows and doors, plumbing and electrical wires.
In the last two weeks the group has managed to finalize all the finishes and details such as the floor, the ceiling and the plaster of the walls. We all look forward to hearing about the experiences of the guests who will be staying here.
Images and Plans
Technical Description
The design process began in Linz, where the students spent two weeks learning about bamboo as a building material. They tested and discussed different designs using physical models that allowed ideas to be evaluated quickly, studied different types of bamboo joinery and designed the building.
Based on the previous experience gained since the construction of the family house in 2019, we chose a typology consisting of a solid adobe unit protected by a lightweight bamboo roof structure. Once on site, we adapted the design to the local conditions. This meant that the final design and detailing was carried out in parallel with the construction work.
After testing different mixtures of local earth, sand and fibre, the students with the help of the local construction team and the children of Baan Doi made about 2500 adobe for the walls, which were left to dry for about 10 days. The size of the mould was 29 cm long, 14 cm wide and 10 cm high.
Due to the cohesive nature of the local soil, it is difficult to prevent the foundation from moving. It was therefore decided to place the entire building on a single concrete slab to distribute the loads as evenly as possible. The concrete slab foundation measures 640 cm by 440 cm and is 30 cm high. On the lake side, the slab rests on an additional concrete beam (30 x 50 cm), which supports the cantilevered terrace, but also prevents the whole building from settling unevenly.
The bamboo structure consists of four main elements: the vertical columns, the bracing, the cantilevered terrace and the roof triangles. The bamboo was delivered to the site in 6m lengths in two different diameters, approximately 5cm and 16cm. The bamboo was treated with borax to make it durable and resistant to insects and termites.
An important step in working with bamboo is choosing the right pieces for the right purpose. For the vertical columns and overhang of the terrace we used bamboo between 2.5 and 3.8m long, while for the roof triangle we created beams by stacking 3 thin logs (5cm - 7cm) on top of each other. The three layers, secured with bolts and diagonal homemade bamboo nails, interlock at the junction to form the main triangular structure. The two triangles were assembled on the ground and then lifted into place. No crane or other machinery was required.
On top of this main structure, the battens are held in place by ropes twisted with custom-made bamboo sticks, a commonly used technique that has the advantage that the joints can be tightened in case of shrinkage or loosened for maintenance without weakening the logs with additional holes. Corrugated metal sheets were attached to the bamboo battens with standard sealed screws.
To protect the adobe walls from splashing water, we used fired bricks in a Flemish double bond for the first 35cm. A rubber sheet was placed on top of the bricks to act as a capillary breaker against moisture. The adobes were laid in an English bond with a thickness of 30 cm, which made it possible to incorporate niches in the bed and bathroom walls. The water connections were integrated into the walls during the bricklaying, the electrical ducts were cut out afterwards, the pipes were embedded in the walls and then sealed with earth mortar. The walls were covered with lime and clay plaster. For the interiors, lime plaster was used for the bathroom and clay plaster for the bedroom. The exterior walls were finished with two layers of lime plaster. The window and door frames were made of rubber wood by a local carpenter.
During their stay, the students also worked on landscape design around the guesthouse, including planting, rainwater, freshwater and sewage management, electricity infrastructure and pathways.