stove wall shield

[Harley]

Harley, now I see what you're asking. I guess I wasn't too clear there: what I was describing was a situation, as suggested in another post above, where there was no stone wall, just replacing the sheetrock with non-combustible millboard. If you just did that, the inspectors in our code jurisdictions would consider it a combustible wall, and measure clearances from the surface of the millboard. If you then added stone that touched the millboard, the measurement would be from the furthest-protruding stone, same as if you'd applied the stone to the sheetrock.

Thanks... got it now..