Rammed earth is a construction system that combines recyclable materials (like tires and cardboard). It doesn't require skilled labor, and is estimated to be cheaper than a frame built house. The walls are energy efficient and are made of adobe or plaster, concealing the tires and cardboard inside. Rammed earth tire construction is cheap and requires little skilled labor. A foundation is poured and then tires are laid along the foundation wall, along with cans and cardboard. The tires are filled with soil. Tires and materials are applied along side this mass and more earth is applied. Then a few inches of plaster/stucco cover the wall. Homes like this are designed facing the sun/south so as to make the most use of the sunlight. In the winter, to maintain the comfort zone stoves or hydronic (water piped under the floor) methods are used. The materials are mostly taken from the site (dirt) and from waste sites (tires abound in landfills) and thus are very cheap. Most estimates put the $$/sq. ft between $30(owner built)-$65(contracted labor). Tires are not toxic products; they are covered with soil, plaster, and a sealant, thus they are not exposed to UV rays, and therefore don't outgas.

 

 

 

 

"The alternatives for roofing materials on a low-slope roof are limited to petroleum based products like cold process tar, Brai and Bituthene, rubber EPDM, paint on Acrylic systems, and earth."

Waterproofing:
These earthen building materials must be waterproofed. First a water sheeting material ie Typar or Tyvek is applied to the walls and then Enkadrain, a waterproofing membrane is applied. A footing drain is also installed to drain the water. Electrical wiring should go under the floor or into PVC pipes in the wall, however, they may not be changed and are permanent. Standard plumbing can be used, but also is not mutable. The walls are very sturdy. They do not flake due to a small amount (5%) of cement binder in the dirt mix. The binder also prevents erosion. The waterproofing should stop any water absorbency from coming through.

Rammed earth is a viable building system for areas of hot air temperatures, and relatively dry air. If the climate is suitable materials are readily available. Old tires are readily available in landfills, and often the dirt from the site or the surrounding area, mixed with a bit of cement binder, will suffice. Actual construction is relatively labor intensive, however can be done by the owner with little training. Construction must occur on the site. Aesthetically, I think rammed earth is quite nice for the "desert" area and should be considered by the Phoenix, AZ, team.