The primary objective of this project was to design a building appropriate for the given climatic conditions and one which factored in elements of sustainability. To achieve these aims, it was decided that laterite stone, native to the region, be used as the main building material in an exemplary pilot project. The building was set at an east-west orientation which reduces direct solar radiation onto the walls, while the walls themselves are additionally shadowed by means of a sharply protruding roof. The building consists of three classrooms in addition to a computer room that is attached to an office space. There is also an amphitheatre with a corresponding size to that of a classroom. This space is a designated sitting area during break time.
Material
Building materials which were exclusively used for this project were: locally extracted laterite stone for the walls; reinforcement insulars for the roof-supporting structure; corrugated sheet for the roof cladding; cement for concrete components; and mortar as well as blades for the windows and doors. The complete walls consist of laterite stone studded by hand and reworked. The refined finishing process of the laterite stones as well as their lamination by means of very thin joints made out of cement were regarded as innovative methods in the region. Also, the suspended ceiling as well as the unusually acutely angled roof structure designed for climatic reasons set new standards. Although exclusively local materials were used, the building is regarded as highly innovative throughout the country with particular attention being drawn by the sophisticated ventilation system.
Construction
All walls are load-bearing and consist of laterite stones that are 30cm thick in diameter. These sit on granite bed stone which protects the building against erosion due to rainfall. The difference in elevation between the area where the office is located and the rest of the building is due to the gradient of the earth and is compensated by means of steps as well as a smoothly angled ramp.
The roof construction consists of 3m broad, modular elements which were welded together and assembled from 14mm and 16mm thick reinforcement iron on the site. These are crooked and are stored in a longitudinal direction with an incline created by concrete girders and the ring joist. Together with the roof cladding made out of corrugated sheet, it comes to an undulation which gives the building its extraordinary appearance. The lower channelings of these waves lead the rainwater away from the building.
The suspended ceiling in each room is made of 3m broad elements that have a hanging structure. They consist of timber cement stones that rest on a hanging construction of thin, flat-rolled steel. In each classroom there are three such elements, which also hang on concrete girders and the ring joist.
Respectively, on the sidewalls of the elements, openings were integrated through which the exhausted room air can escape. All hanging elements are plastered on the bottom and on the top. On the bottom side, they are brightly painted so that incident light is equally distributed in the class by means of the movable shaded windows.
Sustainability
The permeable suspending ceiling, the inclined corrugated sheet roof as well as the completely obvious shaded windows ensure a natural ventilation of the rooms. Compared to the conventional construction method, for which an artificial air-conditioning of the rooms is required, this is the more sustainable solution in the face of fossil resources running out and increasing energy prices. This especially applies to a country like Burkina Faso, which is ranked second to last place on the UN poverty list and which has to cover its complete energy demand by means of import.
Another aspect of this work is the fact that the overall project was carried out in cooperation with young people who had already been trained through previous projects sponsored by the “Schulbausteine für Gando e.V.“ Through this construction concept, not only was a local building material re-valued in form of the laterite stone, but local handicraft was also re-valued, trained and further educated.
