Insulating hearth - Use firebricks instead of vermicrete?

[brennerwilliam]

Hi everyone,

My vermiculite/portland cement mix insulating hearth layer is thinner than I expected (2.5"). Instead of pouring another layer of the vermicrete, would an extra layer of firebricks work instead?

My setup would be like:

-2.5" vermiculite/portland cement
-4" firebrick layer
-4" firebrick layer (oven floor)

Thanks in advance!

[Neil2]

"would an extra layer of firebricks work instead?"

It does not substitute for insulation. I would add another 1 1/2 or 2 inches of vermicrete. Having said that, if yours is a typical Pompeii oven, the 2 1/2 inches of insulation with the firebrick hearth on top should work OK.

[brennerwilliam]

Thanks Neil. I ended up pouring another 2 inches today after your advice.