Global Ecovillage Network/Solution Library/Interlocking stabilized soil blocks

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Interlocking Stabilized Soil Blocks (ISSB) technology addresses both the environmental and economic challenges posed by traditional burned/fired bricks for building houses.

Fired bricks cause serious deforestation: high demand for trees used as firewood for brick production. ISSB does not require any amount of firewood. ISSB has also proven to drastically reduce the cost of building by min 50%: no cement is needed to join bricks together. The ISSB bricks interlock, making the wall stronger.

Materials required:

1. A stabilized soil block machine (manual machine).
2. Soil: clay soil, murrum soil, sand (but not black cotton soil).
3. Cement/lime/sawdust/wood ash.
4. Water.
5. Manpower.

1. Take soil/sand/clay and mix it with the cement. Rule of thumb is a ratio of 1(cement)/6(soil). See the UN-HABITAT link for simple techniques on establishing the exact ratio, which depends on your soil.
2. Mix properly/continuously as you keep on adding water until it is mixed.
3. Take a mixture and put it into the mould box (of your machine/handmade mould) and compress to produce an interlocking block.
4. Remove and put the block in the shade or cover with grass to avoid direct sunlight exposure.
5. Leave it to dry for at least 28 days as you water it for maximum 2 weeks.
6. When they are dry and firm, after at least 4 weeks, they are ready for building.

• https://unhabitat.org/sites/default/files/2020/07/gh077e.pdf