Structure strength and concrete

Hi all,

First up this is my first post here. Many weeks of research have lead me to realise that this is the spot! This place, and its people look amazing!

this is going to be a Pizza Oven / Pitt Smoker combo (The smoker side of things has yet to be added to the plans).

I have been running ideas through my head for a long time now and finally I feel I am getting some where. I live in New zealand so cost is a big thing ( $4.5 for cinder/breeze blocks and $5+ for fire bricks!) so a big part of this build is weighing up what I want with what I can actually have! At the moment this has turned into a compromise between a traditional full brick oven and a cast perlite oven. I understand (at least I think! haha) the trade offs, and well. . . its better to have this oven than no oven!

The main thing I am totally unsure of though is the thickness needed for the slab right under the hearth. I have seen designs that go well over a foot, and yet the perlite ovens can sit on top of a wooden trolly with wheels. Obviously I sit somewhere in-between. I don't know where!

Sorry for the VERY crude sketchup drawings. Im learning the software for this project.

Everything that is dark grey is a perlite+portland mix.
The red are old compressed red bricks ( I know

)
The light grey is cement
Internal dome diameter is 36' - 90cm
the slab right now is 1360x1640x120 CM But has a 50mm perlite insert (the pink)
Using fire bricks for the hearth (not there yet as I'm not sure what size I can get)

To be honest I have only ran the weight calculations on the bricks, But I am guessing there will be around 200KG sitting on top of the slab.

Can I make the slab thinner? Could I move to using a wood frame instead of cast cement legs? If I did use wood it would be more evenly supported right? Could I go even thinner then?

Thanks guys! This has brought me to a stop!

Announcement