Expantion

[brunello8]

I want to pour vermiculite concrete between my oven dome and the brick housing wall. The vermiculite concrete will fill the sides and be poured over the top of the dome. Then I want to lay brick over the top of the dome. I built a 32'' oven will it expand enough to damage the outside brick housing?

[dmun]

The vermiculite should expand at more or less the same rate as the exterior masonry. The interior brick dome will expand more than either of the exterior layers. The cured vermiculte concrete is fairly rigid: I used a one inch refractory blanket between the dome and vermiculite partly because it's more compressable, and might relieve expansion stresses between the two rigid layers. On the other hand, many makers have used the vermiculite concrete by it's self without difficulty.