Curb around the insulating hearth material

[dmun]

You certainly can. The edge of the insulating concrete looks really ragged if exposed, and exposes it to moisture when it rains. You may want to carry up whatever finish you are using on the base to cover the edge of the perlcrete.

[Jack Chastain]

Does it make any sense to pour a concrete curb (4" X 4") around the perimiter of the hearth? It would be poured on top of the 3 1/2" concrete hearth, and would confine the Perlite/Portland mix. I plan to stucco the entire dome as my final finish to reveal the igloo or pomeii effect. Jack