Sand Bag houses are buildings with walls made of sand bags. Sand bags are gunny bags/gunias that are filled inside with soil of any type and stacked high up to form a wall. This offers a good method of walling a house in areas where there are no quarry stones nearby . Any type of soil, including black cotton soil and sandy soil as found along the coast, can be filled inside the sand bags and stacked high up to from a wall.
Sand bag houses can easily be shaped into curvilinear round shapes. These shapes are good for resort types of buildings where occupants are wiling to pay for recreation eg holiday homes in Maasai Mara or along the Kenyan coast.
Sandbag houses cost far much less than traditional houses . Soil is the most abundant and cheapest building material on earth. It costs very little to dig up sand and fill it into sand bags. Sand bags also cost very little, not more than kes 20 per piece in Nairobi. The cost of walling per m2 can come down from the average kes 1000 per m2 when using stones to around kes 400 per m2 when using sand bags.
Soil building has the lowest impact on carbon footprint to the environment since it only takes soil from the building site and sandbags to construct most of the parts compared to other methods where stones have to be transported to the site, hence using up diesel which in turn harms the environment.
Constructing using sand bags is quite fast compared to other methods.
Sand bag buildings usually retain heat from the sun during the day and make the house warm at night and vice versa, making the interiors very comfortable to live in even in harsh climates where its too cold eg Limuru, Molo areas and where its to hot eg Mombasa, Lamu, Garissa and Turkana areas.
Barbed wire is fitted in between the sand bags to offer traction in between bags and make the walls stronger. Others have a wooden support structure spaced around 3 meters apart to offer support. The wide bag shape and wall bracing at right angles offers ample support for sand bag buildings.
This form of building is yet to take shape in Kenya as residentials . Its mainly used by road contractors as retaining walls. Once people learn and experiment with ths, it will become a household feature, now that Kenyan quarries in Juja/Thika, Kedowa/Kericho and Kilifi are slowly drying up. In the next 5 to 10 years, i can predict that machine cut building stone from quarries in Kenya will all be completely finished, so Kenyans will have to turn to sandbags and other building technology options to build their houses.
Francis Gichuhi Kamau, Architect.