What’s the “rule” with regard to enclosing the space around factory built fireplace systems (code references are appreciated)? My thinking is that this should be a completely enclosed chase.
I was able to access these back-to-back fireplaces by squeezing up between the framing from a basement of sorts.
The missing firestop and inadequate clearance were obvious, although inaccessible (flat roof, no attic). What about the spacing between the flues?
They both terminated at the same height from a shared chimney.