Constructing a sustainable campus
In Chalimbana, Zambia CITYFÖRSTER is working on a masterplan for the Chalimbana Local Government Training Institute in order to increase the quality of life of both students and academic staff of the Institute. Besides building a visually more attractive campus, the demand was also to use more sustainable, local construction materials and methods.
The Chalimbana Local Government Training Institute (CLGTI) needed to be upgraded and expanded, taking into account the residential and educational functions and its specific location on the western slope of a hill. The location on the slope of a hill meant possible erosion by excess rain water run-off, and possible flooding for lower lying areas and communities. The new design had to integrate existing constructions, which were a fragmented collection of buildings, into a ‘real’ campus, with a harmonious image, while respecting the natural beauty of the site. Quality of life of students, teachers and staff needed to improve. In addition, the buildings had to require minimal maintenance and energy costs and be built with input of local labour and materials. Climate had to be controlled in an efficient and cost-effective manner. The site needed to be flexible to future needs for expansion.
The main challenge in the upgrade of the CLGTI was in making it not only attractive and sensible, but also futureproof. That required the optimal use of local, sustainable materials, focusing on climate control and energy saving, on integrating the campus in the surroundings more effectively, but also in making sure future expansion would be possible with this design by densification.
Working with natural shading was an important element in the climatic concept: by placing the main orientation of the building East-West, and main façades North and South to avoid the low-angled sun. The buildings completely avoid the use of air conditioning and instead make use of thermal mass, effective shading systems and the potential of night ventilation. During daytime the ceiling stores energy, which it releases and vents during night time. Additional ventilation for classrooms is supported by solar chimneys drawing fresh air in actively.
A new durable water-system will be constructed that improves the local infrastructure as well. The campus terrain is terraced, creating small water buffers that slow down surface run-off rain water, preventing erosion and flooding (see the picture above). Rain water tanks are integrated in each building to harvest water for flooding toilets and other uses. A filter system of reed beds on the lower part of the site will increase the groundwater quality and promote a durable and considerate use of water resources.
Local labour was used in the construction process, as well as local materials, such as adobe, a local by-product of the terracing of the site. Adobe is used as bricks and in rammed earth walls. The double layered roof structure allows and guarantees natural ventilation.
Challenges during the process
Although the design used local materials and very low technology, these two aspects were actually the main challenge in the design development. The use of local material has a bad reputation (“we don’t live in mud-huts anymore”) and their use is not conforming local regulations, although it is widely used in domestic construction. Furthermore, the low-tech approach proved difficult, because the know-how to make the low tech installations (for example solar chimneys) work requires very advances know how (for example thermo dynamic computer simulations) that is not readily available with local suppliers.
Current status and question to the community
The project is currently being tendered for construction.