Earth bag construction is a type of Advanced Building Construction. It is also popular as super adobe. In this type of construction cement bags are used as the form work for the earth.
The earth-bag dome was conceived as a very simple dome structure with a solar chimney at the top to keep the air circulating.
Construction of the earth bag dome:
A pit with inner diameter of 4m and width and depth of 1.5ft and 1.5ft was dug. The rubble trench foundation with the water channel leading to the rain water pit beside was done since it takes very less labour and also demolition waste is all the material you need to do it.The rubble trench foundation was toopped with flat stones. We walked on the stones to make sure they were stable as this forms the base for the super structure.
Then at the center of the dome a vertical pivot pole was fixed. To this pole a horizontal pole was attached with the help of a clamp.
We bought cement bags from the scrap shop. They were of the right size. Any other sack made of polypropylene can also be used.
Bags were made inside out.
For the wall up to sill level the cement bags were filled humid mix of earth stabilized with lime in the ratio Earth: Lime :: 6:1 and were stitched. After filling the bags were stitched.
The curve of the first course was guided by marking the radius of 2m on the rotatable horizontal pole.
Then the earth-bags were rammed and compacted using a rammer.
The horizontal rotatable pole attached with a spirit level was placed at different points of the course to make sure that the entire course was in the same level. Wherever the level was higher more ramming was done to achieve levelling.
In between every course barbed wire was placed. After ramming the barbed wire pierces into the upper and lower earth bag courses and holds them together like mortar.
After the first course was laid we used a reference chain to arrive at the diameter of the next upcoming courses. The chain can be fixed at any point where the first course meets the ground towards the inner surface of the course. The length of the chain is the inner diameter of the dome.
It was kept on top of the last course and was straightened. The horizontal pole fixed with a spirit level was rotated and aligned to the chain and the point where it touches the reference chain was marked (The horizontal pole should be made sure that it is perfectly horizontal by checking the spirit level). Then the horizontal pole was rotated and the point marked was used to guide the curve of the wall.
After the sill level the bags were filled only withhumid soil(Does notdepend on the soil quality). They were laid on the wall, rammed and levelled with the use of horizontal pole and spirit level as explained before.
Shutterings were placed for windows and doors openings.
Velcro plates will be used to fix the door and also to keep the shape of the openings intact.
The electric boxes are fixed on the wall in the same manner as the Velcro plate.
The structure will be covered with chicken mesh which is attached to the bags with binding wires coming from a barbed wire for required grip.The innermost layer will be of cob, then mud plaster and then outermost layer will be lime plaster.