The building structure is made of walls of packed tires laid out on a 45’ x 30’ footprint. The tire walls are 9’ high and follow curved patterns creating a geometrically stable shape where no buttressing is needed. In addition, the lack of sharp corners helps in the event of an earthquake, as stresses would accumulate there and thus create weak spots in the structure. Additionally, some of these tire walls retain the earth located on the Northeast corner of the building.

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 to stiffen it against lateral forces during the construction stage. A 8” deep concrete bond beam is poured on top of the last course of tires in order to tie the whole structure together.

Walls are founded on trenches filled with tamped down gravel and the courses of tires located below the finished floor level are filled with gravel as well. This foundation provides a solid footing for the walls while preventing any water infiltration via capillary action.

The roof slab is a 5” thick concrete slab supported by a concrete beam frame tying into the bond beam and concrete columns. This slab can be used for the creation of an additional level as long as most of the structure above sits on top of the surrounding tire walls.

The roof slab extends beyond the bond beam where it is supported by beams framing into additional concrete columns. All of these concrete columns are founded on individual square footings except for the ones on the West edge of the building which are sitting on a concrete deep beam, which spreads the column vertical load onto the tire retaining wall located directly below.

The interior space enclosed by the tire walls measures 620 sq ft, while the area of the patio created by the extension of the roof slab is 660 sq ft.

The interior slab is made of bricks placed on top of draining sand while the patio 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.

Non-structural walls made of bamboo are added inside the building in order to partition the space. Tire wall finishes (interior and exterior) are made of cob (earth + sand + straw) applied against the tire walls where nails have been added to enhance the cob adherence. The cob fills the voids between the tires and creates a flat surface. On the inside, the walls are covered by two layers of plaster: a form coat (cement + lime + coarse sand) and a final coat (cement + lime + fine sharp sand).

Door frames are made with concrete columns carrying concrete arches. The columns are founded on square footings and cast against the tires, thus providing lateral restraint to the walls. The concrete arches are tied into the bond beam to limit the impact of door openings on the global stability of the structure.

Window openings in the tire walls follow the geometrically-stable arch shape to avoid the presence of lintels. The arch is created through the use of earth bags.

Regarding soil drainage strategy, the foundation trenches of the tire walls present a lower point where any potential water would be gathered before being led to the Southwest corner of the building where a concrete drain tile crosses the retaining wall located on the West side of the building.