building insulation base for bread oven

[janethshea]

We are at the insulation stage (under the firebrick) of our bread oven.
We plan to use a 5 to 1 vermiculite to Portland mix, at a depth of 5-6 inches.
Does this seem correct? We will then put on an inch of sand and level the firebrick. We will proceed with a cob construction.
Any suggestions?

[brickie in oz]

Re: building insulation base for bread oven

We will then put on an inch of sand and level the firebrick.
Any suggestions?

Yeah, dont put an inch of sand just a few mm will do.