This is the third installment of my low cost desert shelters that have been designed with economic refugees in mind. These desert shelters were inspired by Phillip Garlington’s website at Rancho Costa Nada. http://www.ranchocostanada.itgo.com/ His book Rancho Costa Nada: The Dirt Cheap Desert Homestead is available through Amazon and Smashwords.
The subterranean Earthbag Desert Shelter is built 5’-5” below grade to capture the coolness of the earth. This is the easiest way to maintain a comfortable indoor temperature without mechanical cooling systems when you’re surrounded by searing desert temperatures. Building below ground is how desert dwellers have escaped the heat for centuries. Earthbags, in this case sand-filled polypropylene bags spiked together with ½” rebar reinforcing, make exceptionally strong walls to resist the thrust of the surrounding soil. The excavated sand is used to fill the bags. An outer layer of 6 mil plastic sheeting (6 mil poly) serves as a low cost moisture barrier. The roof is built similarly as the Desert Dome Shelter– double layers of ferrocement (rebar, mesh and cement plaster) with recycled insulation such as foam packing peanuts. Pallet floors, possibly covered with scrap wood, plywood or salvaged carpet, are shown as one option. Soil cement (sandy soil mixed with about 10% cement and just enough water to make a stiff mix) would be another good, affordable option. A cellar door is used to protect the entryway from rain, snakes and other pests. Breezes flow through a vent on one end and out the tilt-out window above the door. The vent can be screened to block most of the blowing sand and dirt. One possible option to reduce labor (at a slight loss in comfort), is to build only two or three feet below grade and berm the sides with sand as high as possible to prevent overheating.