Over the past year Equal Aqua has made the transition to using Interlocking Stabilised Soil Blocks (ISSBs) for the construction of new rainwater harvesting tanks and ventilated pit latrines.
ISSBs are bricks manufactured using a manual press machine and consist of locally sourced natural soil combined with small quantities of cement and sand. This makes ISSBs one of the most sustainable options for construction. Traditional fired bricks require wood to fuel the kilns during the firing process. For example, 14,000 tonnes of firewood is required for 10,000 bricks. Where ISSBs are sun-cured in just 28 days, reducing deforestation in Uganda as well as pollution caused by wood-burning.
Besides being a more sustainable option, ISSBs have a greater compressive strength of up to 80%, which allows them to withstand greater loads, have higher thermal insulation (stay warmer inside in cold weather and stay cooler inside in warmer weather) and are more water resistant, making them ideal for the construction or water tanks and latrines.
The bricks are designed with an interlocking feature, requiring smaller quantities of mortar between bricks which speeds up the construction process, and reduces transportation and resourcing of materials. The neat exterior and minimal mortar provide a smooth, visually appealing finish and doesn’t require plastering, further reducing costs and environmental impact of the addition materials and construction which would otherwise be needed.
Working alongside the construction team at Haileybury Youth Trust, we now have the skills and knowledge necessary to make our own ISSBs. During 2023 we purchased two of our own manual press machines, for both curved and flat bricks, with the ability to manufacture up to 400 blocks per day per machine.
We are excited to be able to apply sustainable techniques to our construction and hope to provide the communities we are working with, the knowledge to carry on this approach for years to come.
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