Earthen School - Tipu Sultan Merkez, Pakistan
Ziegert | Roswag | Seiler Architekten Ingenieure was founded in 2003 and is based in Berlin. Their core competency is the use of natural materials, especially earth, in construction. Their projects range from a timber firehouse in Brandenburg, a white earthen home in Berlin's Westend and a bamboo-and-earth school in Bangladesh to historical monuments in the Arabian Peninsula and school projects in Africa.
This project, financed by VEBS – Verein für Entwicklung, Bildung und Selbsthilfe e.V. (Society for development, education and self-help) is an extension of a school building out of earth and bamboo to meet the increasing space requirement due to the rising number of students.
2 earthquake-resistant and climate adapted bodies have been planned, consisting of a heavy earth cube in the ground floor and a light bamboo structure in the upper floor. The construction works have be done by local craftsmen who have been trained in the specific techniques.
This construction has received the Holcim Awards Gold 2011 Asia Pacific.
Comment of jury: 'The jury commended this project because it contributes to all of the competition’s “target issues” in a convincing way. Through engineering and design, a traditional building technology has been upgraded with effective low-tech measures. Bamboo is used in an innovative way, demonstrating the potential in construction of this fast-growing and widely available material, which also counters deforestation. The propagation of the new construction methods amongst the local population aids the establishment of local businesses and improves the economic situation in this rural area. All materials are locally sourced and can be processed with low energy requirements.
The new construction approach shows the rural population an affordable, high quality and durable alternative compared to widely-used, but higher-cost and less environmentally-compatible construction materials. The combined earth/bamboo structure allows two-level buildings which reduces land use. The low-tech but sophisticated approach creates the potential to develop a unique local architecture, and transfer the approach to many other regions, particularly in less-developed countries.'
The earth was mixed with straw by water buffalos and made usable. The first layer of cob was piled up and cut. The second layer was built, with window recesses.
Half of the bamboo poles, needed for the bamboo ceiling spanning over 5 metres, were pierced. In doing so, all inner walls of the poles were pierced with a metal bar.
Afterwards, the tubes were put up straight und filled with Borax – a salt solution.
It stayed within the poles during 14 days. This kind of treatment is known as the least harmful one for the environment.
The lintels for windows and doors was made of 5 bamboo poles wrapped with straw and formed part of the fourth cob layer.
The ceiling structure consists of a triple-layer of bamboo culms with the central layer arranged perpendicular to the ones above and beneath. They were fixed with steel dowels and laces. An overlay of planking made of split bamboo culms was placed on the central layer and filled with a straw-earth mixture as the floor finished of the upper level.
The bamboo elements were constructed in special mounting devices that allowed a measure of pre production and meant the components only required assembly. The beams forming the veranda were already complete and most of the first floors structural elements were prefabricated.