We are cobbing

The cob slipforms are working well. We are filling them all the way up to top and then advancing around the circumference at roughly a 45 degree angle, plopping and slopping cob as we go. We will see how far we get before winter sets in…

Vanessa and Jamel mixing and placing cob.

Here are the slipforms. The forms themselves are 18” tall and are holding the cob in place with 1/4” hardware cloth. After we make it around the perimeter, we’ll unscrew the wood forms and slide them up 18” and start the process over again. Using forms give nice straight walls and makes placement easier. For a 9’ wall we will do six layers. We can also mix and place cob with a small skid steer to speed up the process, but for now we are just using the cement mixer. The height of the rebar is 9’ and represents the end height of the masonry wall. Embedded in the last 8” will be a U-shaped cement block for the bond beam. The rebar will come up through the bottom of the U-shaped cement block and then be all tied together in a circle, and concrete will be poured. The rebar going through the cob wall from the footing to the bond beam will counteract wind uplift on the structure. Also poured in the bond beam will be anchor bolts for a top plate. The roof rafters will go from this top plate to the wood-framed two story center octagon.