How to build a Pizza Oven

Step 7 Adding insulation

After baking a couple of batches of bread and pizza, i added a layer of insulation. My oven was almost a 100 deg Celsius 212 deg Fahrenheit on the outside, without insulation.
If you want to do this, think of it from the beginning. That means plan your foundation a little wider. I planned my insulation from the beginning, but i wanted to see how it works without. After applying 8cm/3.5inches of insulation made of Perlite and clay, the outside temperature dropped by half, keeping the heat much longer. You can use different materials for insulation, my choice was a foamed mineral. You could use Vermiculite or pumice, but straw or coarse sawdust from a chainsaw would also work. Maybe you need to make a thicker layer to achieve the same insulating effect. I used a sturdy paint mixer in a electric drill to mix clay, Perlite and water. As you can see, it cracked after drying. We used a silicone cartridge, filled with rather thin clay to fill the cracks. We further made a temporary roof with the tarp we used for mixing and kneading the mud mix. The final roof will be made of fiber concrete(ethernit), but it's up to you what you use. Depending on the distance from your oven opening, it needs to be heat resistant. It worked with the tarp and pine wood without melting or charring, but i will use oak where it gets hot.
We will add a thin layer of clay plaster 1cm/0.5inch when we remove the temporary roof. It's easier to work around the oven without the roof. This is only for the optics and it's not much work.