Well good it is rare to find a mason who actually builds with proper clearances. But i stand by the fact that insulted stainless preforms and holds up much better than clay linersNormal 2" clearance against the house, 4" solid block, another 2"of internal clearance then another 4" support wall before you find the flue. External walls 8" of fieldstone. You'll have to forgive me if I'm fearless. I needed all that room to satisfy building codes for the large throat of the fireplace. External Chimney has 32" of depth. Not your average build. I built all the fear right out of it.