This construction started in November 2019 ! One bedroom and a living room fit in 36 sqm in the middle of a bamboo plantation near a pond. We wanted to build a small and cozy house using as much as possible natural, locally sourced or reused, inexpensive materials. It also integrates elements of bio-climatic design to allow passive cooling and avoid air-conditioning.
Many thanks to the people involved in the construction: Fon (for taking care of people and preparing delicious meals), talented local workers (Long Kwan, Pee Waeng, Peesee), workshop participants and volunteers (Damian, Sonam, Gael, Simon, Natanael, Etienne, Carole, Andrea, Israel, Irene, Cécile, Yohann, Santiago, Michaela, Samuel, Mathias, Audrey, Naro) and our friend Philippe.
Inexpensive
Estimated cost: 100,000 Thai bahts (3,000 USD; 2,600 Euros)
From the design stage, we planned to limit the cost without affecting the strength, durability, reliability and maintenance by using:
- earth obtained after digging our land to make the walls
- cheap local products (rice straw, rice husk, special grass for thatch roof)
- bamboo canes mostly from our land
- reclaimed windows
Ecological
We mostly used locally sourced natural materials to reduce the carbon footprint. Efforts were made to minimize the use of cement (gravel bags and rubble rocks for the foundations). The thatch roof of the yurt is also environmentally friendly, however it will require to be changed every 3-4 years due to possible damage from the weather and insects.
In some cases it is hard to avoid using materials that are either non-natural or with a rather high carbon foot print such as:
- bedroom roof made of metal sheet aimed to be more long-lasting and maintenance-free than other natural options such as leaves, thatch, bamboo etc
- metal structure is more reliable and long-lasting than most timber and bamboo that might be damaged by termites (although teak wood and treated bamboo might have been used).
We chose these conventional materials because part of the project was made during covid-19 pandemic and lockdown. Involving skilled workers or friends was then much complicated.
Healthy
Another advantage of building with natural material is to avoid hazardous building materials, toxic paint, thinner, insulating materials etc
The construction…
Living room
In October 2019, we started to build a yurt out of bamboo. It was installed on a rubble rocks foundation to limit expenses and avoid using cement. 60 bamboo canes were assembled with strong ropes, treated with non-toxic chemicals (boric acid and borax) to protect them against insects. The roof structure was made of 14 strong treated bamboo poles and the roof cover made of local thatch (‘yakaa’), light, cheap and acting as insulating and waterproof roof.
The walls are partially covered with earth using a technique adapted from the ancient ‘wattle-and-daub’ method. Split bamboo canes are placed horizontally, weaved between the yurt canes. Then an earth mix (earth, sand and straw) is put around the split bamboo.
The central pole was later replaced by a single steel pole to provide more space in the room.
Bedroom
The 20 sqm bedroom started in December 2019, and the load-bearing earth walls were made by using three techniques: adobe bricks (dried in the sun), Cob and earth bags. The foundation consists in three layers of bags filled with gravel.
Roof: steel structure and metal sheet. For a better insulation, a double-roof made out of bamboo frame and climbing plants will be installed in 2026.
Passive cooling design and techniques
To prevent or reduce heat, and – of course – without using air conditioning, we designed the house using the following strategies:
Shade: the rooms will be shaded by the surrounding bamboo a few hours in the day. Besides, the two rooms have a large overhanging roof.
Thermal mass: The thick earth walls (40 cm, 16 inches) of the bedroom, combined with several openings will help to cool down the interior during day time. The heat is stored during hot hours then released during the night and the openings help the warm air to escape.
Insulated roof: the thatched roof of the living room provides good insulation.
Double-skin roof: An outer roof made of a bamboo frame and climbing plants will be installed above the inner metal sheet roof, with a 20 cm gap between the two rooves. The roof system will then be naturally ventilated by natural convection (air flow).
Baan Din Doi Natural Building 