We're often asked "how do you make a pizza oven?" and this isn't an easy question to answer as we have seen so many variations and it should be noted, we are not structural engineers. However, there are 3 common parts to the pizza ovens that we have seen.
Usually there is an inside layer, sometimes done over a form; for instance a sand dome 800mm (Dia.) For this we would recommend our Vitraclay Pizza Clay, use straight from the bag and depending on the size of the dome, we suggest 4 to 5 bags. You will only need it to be 30mm approx. thick. It does contain a significant amount of grog so adding extra sand is not needed.
Depending on time of year when making, we do suggest to slow down the drying. It will inevitably crack as the water which is a major part of a clay body will dry out and shrink, but slowly drying will the reduce cracks but not eliminate them.
The next layer is commonly an insulation layer. Our Vitraclay Pizza Clay can be used in this and again, you will need another 4 to 5 bags. The clay can be mixed with straw, wood chips or anything organically fluffy. You want a nice aerated mix, what we call cob. This can be 50mm thick and you could use chicken wire/mesh over your inside layer if you need a keyed surface for it to stick to. As this will be a mud like consistency it will contain a lot of water, so once again consider the drying. Note, that the water will eventually follow gravity and drain downwards. The bottom edges will be wetter or the inside layer. You can repair and you will have to at some point, but use the same mixture as before and simply fill those gaps.
The outside layer defines the shape, this can be to a particular colour or even smoothness. If you wish for a permanent structure you might consider cement fondues, which are sandy renders with a high alumina content that protects against thermal shock. Or you could just use the Vitraclay Pizza Clay neat from the bag once more, to a 20mm thickness. You can then protect against the elements with a covering or roof. If you prefer a terracotta colour, then our Vitraclay Terracotta Clay with Grog is a great alternative.
We have not mentioned the plinth, doors, arches, etc. as there are so many variations to the structures of ovens, and as mentioned before there are limitations to the advice we can give.
But one other product we sell that is loved by the pizza oven makers is our cordierite kiln shelves, especially the round ones which make great bases for the pizza's to go on.
