What is Stabilised Soil Blocks?
Soil has universally been used as a major building material in form of mud, adobe, rammed earth and burnt bricks for centuries. However, when used in any other form other than burnt bricks, such buildings are short-lived as they easily erode when they come in contact with water.
While burnt bricks are strong and water resistant, they consume a lot of firewood. In some areas, as many as 20 trees are required to burn the bricks required to build one classroom. Burning of bricks for permanent buildings construction is not a viable option as in the long run cause’s deforestation.
The other option of improving soil qualities to make it suitable for building permanent building is stabilization with cement as the binding agent. When a small amount of cement (5-10%) is added into the soil and then compressed mechanically to make building blocks, the resultant blocks are water resistant and their compressive strength highly increased making it strong enough to build buildings up to 3 stories high without using columns, when using normal blocks that are cemented together with mortar.
The introduction of Interlocking Stabilized Soil Blocks (ISSB) is gradually revolutionalizing the building industry as the ISSB technology reduces construction costs as cement mortar is not required to lay the blocks, and construction time and labor is significantly reduced.
Comparisons between ISSB, Concrete Blocks and Burnt Bricks
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Advantages of each technology |
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ISSB
Main raw material is soil with an addition of cement
Made with a manually operated block press
No firing required
There is no wastage in production
Fast to build with, and unskilled people can learn how to build with the blocks fast |
Concrete Blocks Main raw material is sand and sometimes gravel with an addition of cement. Requires only a manual hand mould No firing required
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Burnt Bricks Main raw material is clay soil and firewood Equipment required is only a simple hand mould Traditional skills are available in many rural settings |
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Disadvantages of each technology |
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ISSB Requires specialized design considerations and columns at corners and around openings |
Concrete Blocks Consumes a lot of cement Requires sand and gravel, some rare materials in some states of South Sudan Requires skilled people to build with them Compared to ISSB, concrete blocks takes a longer time to build |
Burnt Bricks Traditional brick making has 40-50% wastage Consumes a lot of firewood to burn the bricks causing deforestation Requires skilled people to build with them Construction process takes a long time as the bricks are small, costing more in terms of labor Requires a minimum of 2 months to have them ready for construction |
Click here for SSB Frequently Asked Questions