Using 1" bricks to make a thin dome and then insulating madly. Thoughts?

[GordonAddison]

It seems to me that the firebricks are to stop spalling. And the crucial part of the design is the insulation/thermal mass being high enough to retain heat. So to save money I thought I could construct a thin dome with either a regular brick and mortar exoskeleton or just backfill with a concrete/vermiculite fill. I plan to enclose the whole thing in a rendered box made of blockwork so plenty of room for insulation. The 1"dome will be cut to make it look neater

( probably) and refractory cement used for the dome mortar. The inside would look a bit rough or faceted as the courses would be 4" wide and the visible face of the bricks would be 4 by 9, but it is more about function than aesthetics.

I can't see much wrong with this idea but that's what worries me! I'm aiming for a 39" dome inside.

hope you can add to the thought process. Reading loads of posts that clearly indicate there are as many designs as members!

Regards and thanks in advance, Gordon

[Gulf]

Gordon,

The "concrete/vermiculite" you mention is an insulator. It will not work very well to retain the heat. If you are going this route, think about home brew, grog, and small brick chips for the cladding. Then, a 10-1 mixture of vermiculite to portland cement can be used to insulate the dome. Imo you really need at least 2" of thermal mass for a pizza oven and 4" for a WFO. Normal size firebrick are 9". They can be cut in thirds to split the difference. The cuttings can be used as cladding for even more thermal mass.