For a long time I have wanted to build a pizza oven in the back yard. I shied away from spending $2-3k on fire bricks and cement and decided to try and build with what I had already in the back yard.
I watched quite a few videos and blog posts about building ovens with cob, including this very helpful video by Lizi Qi. These photos track the progress of building the oven.
The first step was to dig a hole for the base and fill it with cement.
Then the steel was mortared in on top and a layer of bricks added to hold it in place. The cavity was filled with sand and glass bottles to insulate the base from the layer of bricks in the oven.
The shape for a brick arch entrance was laid out on the grass and then a wooden frame created to support it while the mortar set.
The arch required some additional wooden supports as the width of mortar between the bricks wasn’t measured properly when they were laid out on the ground.
Prior to constructing the oven, a shelter was built to protect the earth while it dries. I had a piece of corrugated iron left over from a renovation, but the wood was purchased new and is probably the most expensive part of the build.
Wet sand was mounded into the desired shape of the interior of the oven. Usually ovens are dome shaped, but this oven is based on an oval.
A few 1mm cracks appeared as the cob dried out, and these were filled with more clay mixture.
And the first pizza cooked.
The oven retained enough heat for 4 pizzas, but as the door was not a tight fit it was clear that a lot of heat was being lost. With a tight fitting door, it should be possible to keep cooking with the coals removed.
No chimney was installed, as the goal is to cook with heat retained in the earth walls and brick base, rather than continuous radiant heat from the fire.