How important is vermiculite in igloo shell?

[jwnorris]

My Casa 110 was delivered on Thursday and I am getting to the unpacking and layout in preparation to assemble. I am undecided on the final outside shell of the oven - an igloo being simpler that a framed & roofed structure.

I live in Southern California and as you know it does not get very cold here very offen. The oven is outside and will be used for pizza, some baking, and single batches of bread [on occasion].

With that in mind, do I need the four inches of vermiculite over the blanket before I stucco the outside. The oven sits on two inches of Super Isol placed over backer board on a pre-constructed, metal-framed base structure.

I will be photographing the process and any information that I can get will be most appreciated

J W

[dmun]

You will likely loose too much heat without the vermiculite/perlite layer of insulation to get the pizza results you want. Also in So.Cal. all the wood comes from far away and is expensive. With extra insulation you'll use a lot less wood.

[jwnorris]

I'm concerned about space, as I bought a bigger Casa then I had intended to buy - got the Casa 110.

If I cover the oven with 1" plus 2" on InsulFrax blanket, followed by a scratch coat of stucco [using refrax motor and vermiculite] and finally the color coat of stucco, will I be OK.

Thanks,

J W

[james]

Hey JW,

One way of minimizing your space requirements side-to-side is to use 3" of Insulfrax and no vermiculite over the dome. It saves you space and still does a good job of insulating the oven at the top. If you can fit the oven in your space, you will appreciate the extra cooking space inside the oven.

For under oven insulation, you definitely need a layer of vermiculite concrete under the cooking floor. It isn't difficult, or expensive, to add and it makes all the difference when you are using the oven. As an experiment, I once installed an oven on a 3" concrete slab, and it was remarkable how hot the bottom of that slab became after a short period of firing the oven.

If you have any problems, give me a call!
James