Insulation Question for Italian Castable Cement Form Oven
We purchased a four part refractory cement form bread/pizza oven (36" approximately on outside, 32" inside floor diameter) recently to finally put in an outdoor oven. The man had bought it in Italy when stationed there - had same one installed in the villa they rented - they had planned on installing it here when they returned and never did and now moving to a condo. I have the handwritten paper sketch from the place where he bought it - in Italian - suggesting platform height, how to insulate etc :) very very rough.
I have Kiko Denzer's book and have read it several times as well as numerous sources on the web - we seem to be between methods / approaches - not adobe oven/one piece, but not brick and not perhaps the more "modern" full casted piece kits from the US dealers.
We have laid a concrete pad and are ready to begin a platform, insulation bottom layer etc, but have a few questions -
1) what will eventually be the baking floor bottom (the base two pieces) is quite rough - should we mix up either an adobe oven type clay/sand mixture or refractory cement mixture and coat it?
2) The pieces fit together, but don't tightly lock or lip/seal like some of the higher end US type kits pieces - when we put it all together - should we coat the oven outside with same oven clay/sand mixture or refractory cement?
3) We've been discussing pros/cons of doing ceramic fiber / chicken wire wrap versus the vermiculite type approach. I know there is some discussion on the ceramic fiber and inhaling but other discussion that it is safe for use as insulation once installed.
4) We are a bit confused on the base - I understand that there should be an insulation layer in the base - for example sand and glass bottles - but then other postings state should be a weight bearing concrete or wood layer over that I believe and then perhaps fire brick? Our thought was to use cinder blocks to build the base up a bit height - with cement / rebar - then perhaps a weight bearing wood layer (large posts) then perhaps mineral board and firebricks - laying the oven on top of firebricks. Would this work - do we need a sand/glass type layer - instead of the cinder blocks/cement perhaps? Also it seems from reading one of the sections on vermiculite, some people do foundation, concrete slab?, then insulation, then another slab?
Thanks - any help would be great- I am sure in Italy people install the type of oven forms we have all the time - but I cannot find much anywhere about it online and it is just enough different.