velacreations Hatfield wrote:why would anyone want to pound 2,000 tires? That's a lot of work, and thank goodness they aren't paying for labor...
We use a modification of Oehler's PSP method. Earthbags could work, too.
I just read the new Earthship Global Model Operation One: Tire Work
book and they say the 2 bedroom model uses 750 tires. I think the old models where they used several interlinking horseshoe shapes used much more tires. I agree that an earthship could be made from earthbags however I cannot visualize how to attach the bond beam. I think the Earthship could be made nearly as cheap as a wofati but will require different skills ( I say different because a wofati looks fairly equipment, woodwoorking skill intensive).
Tires: Free or may even get paid to take them
Dirt: Free (thermal mass, walls, floors)
Roof: Maybe less expensive than wofati (doesnt need to support living roof) but does require a metal roofing system which is expensive.
Insulation/Waterproofing/Thermal Mass: Same as wofati
Windows: Same as wofati? Maybe more unless you do some creative sourcing.
Offgrid power: wofati requires a well pump and probably water softening which have large power requirements ( a well pump cant be DC due to the head needed on the pump) while Earthship systems have very low power requirements (they recommend a 2kw solar setup - about 8000$ if you do the install and before any rebates) and run completely DC- AC is only for convenience and the rooftop rainwater catch uses gravity instead of fighting it. Rainwater needs no softening.
Sewage: Water softeners make septic tanks not work well due to the high salt content not to mention engineered wetlands.
Labor: Earthship more but possibly made up for in longevity? Wood underground just seems problematic. A wofati seems to require more digging while an earthship is built on the surface and bermed.