A cob bond beam was constructed to provide a flat level surface for framing. Just as described in a previous post, cob is a mixture of clay, sand, and straw with water to taste. The ratio is 1:2.5:1 respectively. The straw provides tensile strength, the clay is the binder, and the sand is the aggregate. Cob gets its strength through downward pressure and integration, make sure to push down with your thumbs and work the straw through. We set up strings to let us know where our bond beam needed to be built out to. Next, cob, cob, cob!! Check with your level as you go and adjust. *As we were cobbing, Chris went around and drilled holes on top of the rocks about 3 feet apart, filled with epoxy, and set a metal thread.
Once the bond beam was complete, we cut base boards and drilled holes where the metal thread sits, so that the board could be bolted onto the cob and rocks. This ties in the walls to the foundation. We used 2×6 studs to frame the walls, taking into account windows and doors. Also, since the east and west walls were planed to be straw clay insulation, so we included latter trusses, which provides solid wall integration.