Earthbag houses have walls made from polypropylene bags filled in with soil.
Cost of wall.
Cost of 1 bag of dimensions 850mm by 450mm by 100mm is kes 20. 12 bags make 1 m2. Cost of bags per m2 =12 x 20 =kes 240.
Cost of soil.
Assuming the soil is available on site for free, the costs will be only labour costs.
With Manual labour of kes 500 per day, a man can dig up 3m x 3m x 0.5m =4.5m3 volume per day.
One sack contains a volume of 0.7 x 0.45x 0.1=0.0315 m3 of soil.
One man can fill in 142 bags per day. At a cost of kes 500 daily, this works out to kes 3.50 per bag. For 1 m2 or 12 bags, this works out to kes 42 per m2.
Cost of earthbag walling per m2 is kes 240 plus kes 42=kes 282. Add miscellaneous to total kes 300 per m2.
This is the lowest cost possible for walling compared to stabilised cement blocks at kes 500 and stone at kes 1000 per m2.
A 30m2 bedsitter room, with 64m2 wall surface, will cost kes 19,200 for walling.
The thick walls are strong enough to carry heavy loads hence another storey can be added on top. Buildings such as Fort Jesus, standing till today after construction 500 years ago, have similar thick sized walls which support several storeys.
Its also easier to create indent patterns which can be infilled with glass blocks or glass plus LED lights to create interesting wall facades.