Hello, I have been wrestling with this question for quite some time. I have a two story house with a concrete block chimney with clay tile liner. I have a oil fired forced air furnace with an add on wood stove piped into the same chimney. I have been heating my home with this set up for close to 30 years so I am not a wood burning greenhorn. I have never had a chimney fire or at least one that I was aware of. I keep the chimney clean and burn only seasoned hardwood. My question is that my chimney has about a 3 inch air space which goes up all the way into the attic and adds alot of warm air into the attic which I think causes ice to form at the eaves. Would I be making a big mistake to insulate around the chimney where the chimney extends into the attic? What about insulating around the whole chimney inside the attic? I would guess the outer block temp gets pretty warm but not over 200 degrees F. Although, a chimney fire, if one did occur, could approach or exceed that temp..... Or should I just leave well enough alone and put up with the ice buildup at the eaves?
ps I have about a foot of fiberglass batt insulation in the attic floor.