The plan is to put in a rubble trench foundation. A rubble trench is a trench filled with rubble or gravel. Clever eh? The benefits are of the rubble trench are: No concrete required. The trench will be filled up to grade level and the building will be built directly on it. The rubble drains water away from the building. A moisture barrier. Water will wick up through the soil and concrete through capillary action. With a rubble trench they are air gaps that stop the wicked action. The rubble trench distributes the weight of the structure. Sounds great except for the whole digging the trench part in hard packed caliche soil. Caliche is a soil that has been cemented together by lime (calcium carbonate). Lime will prove useful later in the building process but for digging the foundation, not so much. Fortunately, we just have to get below frost line which in central Texas is like 6 inches. We're going for a depth of 12" - 18". For the job we rented a trencher which

As a test project for working with earthen materials I'm planning to build a small tool/storage shed. For the wall system I'm using cast In-situ Adobe T-brick technique. With traditional adobe, bricks are made in large forms on the ground. Once the bricks have dried they are used to construct the wall. With the T-brick method individual brick forms are used to make the bricks in place. These rectangular forms measure 12-18" long, 12" wide and 8" tall. In additional there's a another 8" tall piece of wood attached to bottom of the rectangular form (See image below). When constructing the wall, several forms are place end to end on the wall and packed sequentially with Adobe mixture. As, a block firms up the form is removed and placed at the end of the row. In the next layer, the block locations are staggered so that gaps in the layer below can be filled in. This also serves to lock the layers together. Take a look at this article regarding buil