Earthen Oven Construction

During the past week I had the pleasure of building an adobe oven with a group of eager Permaculture students. We built the oven as part of the Practicum portion of the Permaculture Design Course that we just hosted. I highly recommend to anyone interested in building their own adobe oven to pick up Kiko Denzer's book called Build Your Own Earthen Oven (Hand Print Press, 2007). This book guided another group of friends and volunteers and I to construct an oven in 2004 at Finca Carolina. Anyone familiar with Finca Carolina has probably tasted the delicious pizzas that come out of that adobe oven.
Based on years of experience with our own adobe oven I realized two design improvements that would improve functionality and flow of the oven. One was to have a grill in close proximity to the oven where I can put the hot coals after removing them from the oven. Secondly, I realized that a reinforced doorway is needed in order to prevent damage to the clay from placing and removing the door.
We were lucky enough to have an existing outdoor kitchen with a grill and a concrete floor large enough to house this large oven. A local builder helped us to first construct a cinder block box. The box was filled with rocks, concrete debris,gravel and then finally sand. On top of that sat a floor of refractory bricks onto which we marked a 36" circle. This would be the eventual diameter of the oven. We then made a dome of wet sand and covered it with wet newspaper.
Upon that we began to add our various layers of mud. The first layer was a 5" of a clay and sand mixture. See Kiko's book for details about determining correct proportions. This was followed by an insulating layer the same thickness and components but with straw. Finally, the whole oven and cinder block box was plastered with an earthen plaster.
After about two weeks the oven will be ready to begin burning small fires inside. Once the oven is dry and hard it will be ready for pizza and bread baking.