The building consists of three adjacent double-story earthbag domes along a West-East axis. The domes have an internal diameter of 20’ and a total height of about 24’. The domes follow the shape of an inverted catenary as three dimensional representations of the arch action. In addition, semi-circular vertical earthbag walls are added between the domes to create four bathroom spaces.

Earthbag construction uses stacked courses of polypropylene bags filled with a mix of earth, sand and binder (cement for bottom courses and lime for top courses). Two lines of barbed wires are laid out between each course to interlock the bags.

In order to save on material quantities, three sizes of bags are used on each dome: 20” wide bags at the bottom, 18” wide bags around the middle, and 15” wide bags around the top of the dome. However, these gaps in width are not apparent on the final structure as they are hidden with thicker layers of exterior finishes.

Each dome is surrounded by a horizontal earthbag buttress added around the bottom of the dome wall. This creates a tension ring able to withstand the lateral outward forces stemming from the balance of the dome’s internal forces.

All earthbag walls (including the buttresses) are founded on a course of tires filled with gravel. This foundation provides a solid footing while preventing any water infiltration via capillary action. Above these tires, two courses of bags run continuously at the bottom of every earthbag wall in order to limit the impact of the door openings on both the action of the buttresses and the global stability of the structure.

All window and door openings in the earthbag walls follow the geometrically-stable arch shape to avoid the presence of lintels.

The material used for the ground floor slab varies and can be concrete or cob depending on the location in the building. However, regardless of its material the slab is always placed on the top of a 4” thick layer of gravel in order to avoid any contact between the concrete and ground water.

Similarly, the first floor slab is either made of a 4” thick concrete slab with permanent bamboo formwork or 2” wooden planks but it is always carried by bamboo members filled with reinforced concrete ends embedded in the earthbag walls. On the South side of the building, the first floor slab extends beyond the dome and bathroom walls to create a balcony space. The balcony space is carried by bamboo members filled with reinforced concrete cantilevering from the earthbag walls. The slab extends symmetrically on the North side of the building with the exception that the supporting bamboo members frame into concrete beams resting on concrete columns.

The first floor slab is accessible via two sets of stairs located along the two outer domes. The stairs are made with ferrocement and carried by bamboo members filled with reinforced concrete cantilevering from the earthbag walls.

Interior finishes are similar at both levels, made of two layers of plaster: a form coat (cement + lime + coarse sand) and a final coat (cement + lime + fine sharp sand). Regarding exterior finishes, ground floor exterior finishes are made of cob (earth + sand + straw) except for the buttresses which are covered by a layer of mortar (cement + river sand) instead. First floor exterior finishes are mostly made of cob and eco-bricks (plastic bottles filled with trash). They are covered by shingles made out of plastic bottles nailed to the earth bags.

Regarding rainwater drainage strategy, the North half of the outdoor first floor slab slopes towards the Rain Harvesting Corridor located at the North of the building. The South balcony slab slopes towards two lower points located at the Southwest and Southeast corners of the slab where drainage pipes evacuate rainwater.

Additionally a septic system is associated with the building in order to treat the greywater coming from the sinks and the blackwater coming from the bathrooms.