Thread: Not a Rover post Vermiculite/perlite

Hi all i am making a pizza oven.
I am at the stage were, i am building the slab for the pizza oven to sit on. The book i am following says to use vermiculite or perlite in the top part of this slab. I am not to sure why?(i think for insulation).

Does anyone in brisbane know were i can get about a quarter meter, its $10 a bag from Bunnings i need heaps.

Thanks all

I assisted as technical advisor on the construction of one of my mates wood fired pizza oven. The perlite or vermiculite are insulators and also they take up space and are light therefore do not increase weight anywhere near as much as sand or screenings/blue metal in a slab or in the oven cladding.

I prefer vermiculite as perlite crushes easier and results in losts of dust.

You can get both materials from hydroponic garden supplies.

The oven we made had the slab then 25-30mm of sand then clay pavers as the base.

The cladding was a layer of bricks and clay to jam between the bricks then about 50-75mm of perlite and clay as well as some hessian rope fibers then for the outer layer another 50-75mm we used the clay with vermiculite.

If I was to build another a would use only vermiculite and I would use chicken wire intead of the hessian to help hold it to gether. Sand can also be used to bulk the clay out and help stabilise it as clay is very reactive to moisture and will crack as it dries, the sand does not expand with moisture so does stabilise it a little. The vermiculite does a similar job as it does not expand as much as clay but does absorb a lot of water.