Building with Good Earth
Kiln-fired bricks are by far the most common building material, particularly in rural areas. The manufacture of these requires enormous amounts of heat, which means that vast amounts of timber and charcoal are being consumed. It also emits a lot of CO2 (an important consideration in the global warming scenario). The cement used in building is also energy intensive and expensive. So what are the alternatives?
Stabilised Soil Block Technology compresses moistened subsoil mixed with minimal cement into building blocks. The blocks are "cured" not fired.
ISSB presses compact moistened subsoil mixed with minimal cement into building blocks. The presses are manually operated, require little maintenance and are guaranteed for seven years. They cost around $740. Assuming soil types are favourable, a team of four
with basic training, can make up to 500 blocks per day using one press. The presses are easily transported, making them accessible to remote communities. Close cost analysis reveals savings of around 20% for construction of houses, classrooms, clinics etc and a 50% reduction in the construction of water tanks and sanitation facilities.
Recent modifications - designed by the Faculty of Technology at Makerere University, Kampala - have transformed the potential of this technology. The new presses use the same process, but with increased compaction produce Interlocking Stabilised Soil Blocks (referred to as “ISSBs”). There are two types:
1. Interlocking straight blocks – for basic building
2. Interlocking curved blocks – for construction of water tanks and sanitation facilities
The blocks are stronger and more durable than fired bricks. The interlocking design strengthens all construction work, and enables quicker construction with lower levels of masonry skills. Considerably less mortar is required, and his significantly reduces the cost.
Did you know…
10,000 Bricks are required to construct a two-room house or a classroom block. To fire them requires 10 tons of firewood and causes 7630kg of CO2 emissions. The situation in Uganda, typical of Africa, as a whole constitutes a terrible irony where the development of infrastructure and community assets threatens the vital ecosystems on which people depend for their survival and hastens climate change.
Between 1990 and 2005, Uganda lost 1,297,000 hectares of forest (18.4% of the total). The alarming rate of deforestation across the whole of Uganda prompted research into Stabilised Soil Block Technology by the University of Makerere in Kampala.
Good Earth building schools
Good Earth is a small non-profit working in Uganda using ISSB technology. It is working with Climate Care UK to promote the sale of ISSB presses in Gulu in Northern Uganda and to calculate the carbon savings arising from their use. It is also building a classroom block and teachers accommodation at a school in Jinja (in Eastern Uganda):
“Perhaps the greatest success of the project lies not in the construction work but in the level of student participation. The simplicity and safety of the technology has enabled many of them to become actively involved, making blocks and helping with the construction of their own classroom. They have had the chance to acquire new skills, earn themselves some money and to learn about the developmental, environmental and health benefits of an appropriate technology. The headmaster has been so impressed that he has encouraged teachers to initiate discussions about ISSBs in technology and agriculture lessons. The students have also become advocates for the technology and interest in the local area has been considerable.”
If the project is successful, it could provide a model for creating new educational facilities across Africa.
What you can do
Organise a fundraising event and try to raise enough money to pay for one ISSB press. This will go on working for years to build homes and schools, create employment for the team running the press, and save CO2 emissions. perhaps a group of people going on holiday could consider sharing in the cost of one press to offset their flight emissions.
Good Earth Trust: www.goodearthtrust.org.uk
Build IT International: www.builditinternational.org
Ugandan Rural Schools Initiative: www.ugandanruralschools.co.uk