I find it's a general problem that people want to take a concept from one location and apply it everywhere. It once made me formulate the saying; "Don't build igloo's in a desert!". Back in year 2000, when I visited Mike Reynolds at the 'ground zero' for Earth ship development; 'The Greater Earth' in New Mexico, I understood why they used tires; There were not enough clay for miles to ram any earth, no trees of significance. Basically a desert. That's also the reason why they place the water cleaning system in the house, as well as the rainwater catchment. This is much the case for the 'Superadobe', a technique developed in a barren part of Southern California, where earth gets poured into an 'endless' plastic tube, (typically mixed with min. 15% concrete), and then made into load bearing domes. Excellent technique for low-income homes in tornado endangered hot Florida, but definitely not in cold climate countries.