New to the forum so I'm going to ask the stupidest question first!
During lock-down I'm constructing a wood fired oven in the garden to replace oven cooked pizza and a poor BBQ. I've watched loads of YouTube videos and got some good but divers information on various techniques.
I've got a brick-walled stand/base in construction and I'm planning the next stage. My proposal is to have a 75 mm thick refractory concrete base, a 75mm Vermiclite concrete base and a 75 mm cooking layer made of reclaimed bricks (which I already have).
The daft question that only someone new to this could ask is what order do the two concrete base layers come in? I'm guessing that the refractory concrete base goes under the Vermiculite base? Even I can work out that the cooking layer goes on top of both!
Have I got the thicknesses of these layers sufficient? Is there any other cost-effective way of adding to this set-up or maybe doing it completely differently? I'm not intending using mortar between the cooking layer bricks but do I need a fire-proof mortar layer under them? Any suggestions for the proportions of the mixes for the two layers? Can I put chicken wire in either or both concrete layers to strengthen them or is this a no no?
I'm going to construct a dome shaped oven, again made of reclaimed clay brick, on the concrete base, held together with a refractory concrete and with fire-proof mortar used carefully inside to plug any gaps.
Any tips, links ideas would be gratefully received!
First, don't use fire cement, it's expensive and unecessary; use 'home-brew' which is Sand/Cement/Clay/Lime in the ratio 3-1-1-1. It is cheap, forgiving to work with and perfect for a WFO.
As to your base layers, your cooking floor should be about 2" thick, this needs isolating by an insulation layer (vermicrete) and this insulation should meet the insulation over the dome. What these two layers sit upon is largely material as it won't be used to store heat, con-blocks are commonly used. The cooking floor can be made of refractory bricks or even storage heater blocks, but it must be a layer capable of storing heat without degrading.
Having built the stand and allowed time for the vermicrete to dry out, then the floor bricks can be loose laid on a bed of sand for levelling, no mortar required.