I think its frowned upon unless its an insulated flue (burn hazaed)
We did that with a ground floor wood burner in a three storey mediaeval house, the fire resistant plasterboard ductingâs a bit bulky, but works very well, particularly on the top floor. You can also get an inexpensive fan and metal ducting kit to draw heat horizontally from the flue through the roof space. We installed one of those at the same time for the guest suite, but in retrospect, it wasnât really necessary
what problem did you have with a mezzanine bedroom?
we too use those wood burner fans that you place on top of the woodburner they are very efficient at moving the warmed air around the room. We also have a combined smoke and carbon monoxide alarm in the room, as I hope, has everyone else.
The noise from below, or the noise from the bedroom if you are below.
The comment was about sound transfer