A German architect, Oliver von Malm, has developed a construction system that enables the residents of the Kibera slum in Nairobi to build higher quality structures with ease.
The construction system is based on a hollow concrete brick that can be manually assembled and dismantled in a push-fit system without using mortar.
Von Malm pointed out that the traditional construction system in the slums is a catastrophe from a climatic point of view.
The two traditional construction methods in Kibera include one based on a wooden frame, wet soil, and a corrugated iron roof made with or without an outer layer of plaster to prevent the soil from erosion. The second method consists of an entire wooden frame structure covered with corrugated iron sheets.
The architect says this is the first mortar-free construction system using hollow concrete blocks designed to make it possible to build houses in large quantities.
The construction components can be assembled and dismantled by hand in a push-fit system. This is an advantage since it allows slum residents to own their houses even if they don’t own the land since slums are informal settlements.
“If the land is reallocated, e.g. for road construction, the inhabitants must leave the land – and their houses. The new construction system would simply allow them to take their homes with them,” he says.
The walls of the 50-centimetre hollow blocks measure just 2-4 centimetres in width and the cavities in between are filled with soil instead of concrete.
A new feature is designed to create a floor plan with infinitely adjustable angles based on a standard block construction whereby the push-fit system becomes flexible whenever the direction that the block is lying in is changed.
A stable wall is created each time the blocks are layered in the same direction each time. If, on the other hand, the direction that they are laid is alternately rotated by 180 degrees layer upon layer, a wall is created that can be adjusted to any angle.
This feature would enable flexibility in floor plans for properties in the densely populated slums where space is often uneven.
This construction system could provide a single-family home for as little as Ksh. 140,000 to Ksh. 280,000 and enables building at four to five times faster than conventional methods according to Von Malm.
“A concrete house is a bit of a status symbol for the residents of Kibera. Many of them wish they could live in one of these houses one day. At present, however, it is still unclear whether they can really afford such a house or whether it will have to be subsidized,” says von Malm.
Owing to the low concrete usage, he was able to keep the costs below the level of traditional construction even though this is only over a cumulative period of ten years.
“It could be the case that the initial investment can’t be raised and long-term thinking is not an option. In the slums, people live from one day to the next,” he said.