Re: pizza oven heat retention The oven is insulated with a 12cm coating of baked stone (similar to vermiculite), portland cement and lime. On top of that i have another 10cm of concrete cladding. The initial firing was done with gas and after 26 hours of continuous firing the top of the oven was barely warm. No matter how much I fire it, the top never gets hot and has never cracked, that's why I think it must be the single layer red brick. |