Sand instead of Vermiculite?

[asudavew]

I think it's a great idea to increase the thickness of the vermiculite layer.
But I would just lay the floor bricks flat and not on their sides... it will take you much longer to get the floor hot and the floor is the hardest part to heat... IMHO

Dave

[wlively]

Have got to second Dave's post. The floor take a very long time to heat up. Better to go with a second layer of insulation under the floor (2 boards or 3+" vermiculite and 1 board) than sideways bricks.

[Xabia Jim]

Dittos to the advice provided....the floor is often the hardest to get hot so flat bricks and good insulation under it will work for most applications.

If it was a commercial operation or being used for days on end then the bricks on the side would be a good idea.

most of the applications here are for the home baker and the design works well.

I did insulate my hearth after installation but it was a modular oven application. When I built my second oven, I used 6" of perlcrete....you learn more as you go along......