The basic materials needed to build a clay oven are clay and bricks or rocks. Materials to build a form will also be needed, and a form made by mixing sand and water is commonly used. Before starting construction on the platform or base, one must decide on the size of the clay oven. The size will be determined by the type of food that will be baked in the oven.
After deciding on the location of the clay oven, the next step will be to build a base or a platform for it. The platform can be made out of wood, rocks, or bricks. If a wooden platform is built, it must be topped with a fireproof barrier constructed of bricks or rocks thick enough to absorb the heat from the oven without damaging the wood underneath.
When the fireproof barrier is in place, it is time to build the form. Mixing sand with water and forming it into a domed shape is an inexpensive and easy way to make a form. Just enough water should be used to make the sand hold its shape. If the sand dries out before the shape is formed, more water can be added.
Once the sand form is completed, it is time to add the clay. It needs to be applied carefully so that no pressure is put on the sand form that might cause its shape to change. The clay needs to be the same thickness all the way around. After this step in complete, the clay should be allowed to dry just long enough to be firm, and then the oven door can be cut out.
When cutting out the door, it is critical that the door be 63% of the oven’s height. A taller door will cause the oven to lose heat, while a shorter door won’t allow the smoke to escape. Once the door has been cut out, the sand can be removed.
The clay oven must be left to dry completely before use. It is common for cracking to occur, which can be repaired by adding more clay to fill the cracks. Since a clay oven can be damaged by the elements, some kind of cover should be constructed above it.
Building a clay oven doesn't have to be an expensive project. Materials needed to construct an outdoor oven can often be salvaged from other projects or donated by friends. A local freecycle group can also be a good source for supplies.