The building is the bathroom of a house which has three other rooms: a kitchen, bedroom, and latrines. The bathroom presents an 81 sq ft interior area with a bathtub made of cob (earth + sand + straw).

The primary building structure consists of 7’ tall walls made of packed tires. The walls follow curved patterns creating a geometrically stable shape where no buttressing is needed. In addition, it allows to avoid the presence of sharp corners where stresses would accumulate in the event of an earthquake, thus creating weak spots in the structure.

The house is built along a rammed earth tire retaining wall following the West-East axis. Thus, the tires located on the North side of the building are also part of the retaining wall.

Tires are filled with the earth taken out during the excavation stage, and non-biodegradable waste. The tires are stacked in a running-bond pattern to maximize interlocking between courses. Additionally, horizontal rebars are laid between two courses about halfway up the wall in order to stiffen it against lateral forces during the construction stage.

A concrete bond beam is poured on top of the last course of tires in order to tie the whole primary structure together and facilitate the connection with the concrete roof. Walls are founded on trenches filled with tamped down gravel and the first two courses of tires are filled with gravel. This foundation provides a solid footing for the walls while preventing any water infiltration via capillary action. Similarly, the concrete slab is poured on top of a 4” thick layer of gravel in order to avoid any contact between the concrete and ground water.

The bathroom roof is a flat concrete slab with bamboo permanent formwork. The roof is flat not as a structural choice but a constraint due the shower water tank it needs to carry.