Bee Hive Oven

Building an wood-fired oven out of earth

Ideally you would want to build a stem wall to raise your oven to about waist high. Your base bricks should sit on an insulation layer to reduce the heat loss out of the bottom of you oven.
Insulation is air pockets. Think of heat as moving molecules. As the molecules get more excited, they move faster, creating more friction which produces heat. The closer your molecules are, the easier it is for them to excite their neighbor. Air pockets create larger spaces between molecules than tightly packed earth. Larger air pockets can be created by placing empty glass bottles in this area then infilling around these bottles with a clay slip & fiber mixture (we used bark dust or fine bark mulch for fiber on this project). The clay slip/fiber mixture will eventually burn out the fiber and turn into a clay sponge full of tiny insulting air holes.

We started with a pre-cast cement disk on a pile of pallets. I’m not a big fan of cement. It’s toxic, it takes TONS off energy to process… but it was efficient for a weekend workshop. On top of that we float a thin layer of clay slip, then create grooved surface (just like setting tile). Notice the bricks that will be placed in the door of the oven stick out a little past the edge. This is an important part of the design. It allows the metal bucket to fit under the doorway to catch the everything as the fire is cleaned from the oven.

We previously decided the pattern that the oven floor bricks would be laid in… There’s nothing between the bricks; they are just slid into place tightly next to each other, and leveled by gentle taps. The crevices between the bricks will eventually fill with ash.




ensuring to pack the edges tight




In the slides that you miss here we drew a circle on our bricks and molded the interior of the oven with sand. Our door was pre-built. We used the hight of the door to determine the interior height of the oven. The door should be around 66% the total height. We covered our mound of sand with wet newspaper. The newspaper is only there as an indicator of where to stop when removing the sand.

This image is taken as the cob layer is just finished. This is the innermost layer. We made this layer 4-6 inches thick; an even thickness throughout the whole shell. It is a mixture of clay rich soil and sand. Now that this section of the shell is complete, we whack it with boards to compress it. Careful not to disturb the structure of the sand form underneath.




After whacking it to compress the clay/sand and using a board as a float to smooth the surface.




Next comes the insulation layer. We put in an experimental expansion layer of cardboard to lesson the cracking of the finished oven. I haven’t heard back about how that worked out.




Initial Plaster: we use an earth based plaster that is typically mixed at somewhere around 4 parts sand – 1 part clay rich soil (depending on the soil content).




Jerry wanted a Bee Hive shape, so we utilized the natural plaster as a sculptural medium and created an exterior facade. Here’s Kiko standing next to the finished oven.





I would like to thank Kiko Denzer and Hannah Field authors of
Build Your Own Earth Oven

and Jerry & Jo Dhooghe at BRIDGEPORT FARMS & GARDENS