what dimensions of hearth would I need if I have a combustible wall and floor? Only rear of the appliance will be near the wall and sides won't be near anything (other than floor as stove is not being raised)

Hi, thanks for your enquiry. You would require a full stuctural hearth that is 12" infront of the unit and at least 6" either side with a 2" over hang at the back. The stoves distance to combusibles with the wall will then need to be met as per the manual.