Interlocking Stabilized Soil Blocks, 1993–2013
In Uganda’s urban areas, fired clay bricks are among the most common building materials, but increase soil erosion and contribute to deforestation and air pollution. Interlocking Stabilized Soil Blocks (ISSB), an affordable and environmentally sustainable alternative to fired bricks, are made from soil stabilized with 5% cement, compressed in manually operated machines, and dried in the sun. In the 1990s, Moses Kizza Musaazi of Technology for Tomorrow developed a double-interlocking system for the blocks in which ridges on each block fit into slots of corresponding blocks. The blocks increase the structural stability of built walls while reducing the amount of cement needed as mortar. ISSB are made onsite, reducing transportation and construction costs.