My new WFO 800mm pizza oven.. need help with my hearth!!

[Trizzy]

This is my first build, as always I jumped in feet first, without doing proper research... well, I did what i thought was enough, until I came across this forum.

I've already built the block work and I've laid a cement, sand and gravel, re-enforced steel base only approx 2 inches thick.
Before I get ahead of myself, I need to pause, stop being a know-it-all and get advice from the experts.
Please let me know what else I need for the Hearth and cooking surface. For the 800mm dome I've got fire bricks re-claimed from a 1920's UK fire place. Also I've been reading quite a lot about home brew, also I've read lots of different recipes … What is the recommended refractory mix??

[david s]

An 800 mm oven will be a heavy beast. Normally 4” thick concrete slab reinforced with steel is required. However if the span between piers is reduced so the piers are more directly under the load you can probably reduce the thickness/strength of the supporting slab. You may be able to fit another pier in the centre to support your slab. Post a pic so others can suggest solutions.

The homebrew mix is 3:1:1:1 sand, Portland cement, hydrated lime and powdered clay.