Our house will be 2 superadobe wedding rings the smaller interior will be 2 stories and the larger exterior will be 1 story with a roof deck overtop for viewing ships coming home and forest fairies. We chose to go with concrete columns for reinforcement rather than buttressing to save space on the interior. Also we needed extra reinforcing because we are building a 2 story structure which is not as common with Superadobe. The trench you see is for our stone foundation. We are in a low valley with some water flow so we chose stone to keep our earth walls up and away from any potential water flow. Another note on foundations in Mexico, it is standard to pour concrete directly on the dirt but this is not advisable because it weakens the concrete. Also a standard practice in the states that is not standard here is putting gravel around the top lip of footings for drainage. Basically you never want concrete touching the dirt because it will suck up ground water into the walls and also in dry conditions suck out water from the concrete both of which weaken the concrete. We had them lay down black plastic before pouring the footings and fill the trenches around the walls with gravel as we move up. Lots of houses suffer from mold problems down here so we want to try to avoid that.