Insulation, Radiant and Vapor Barriers - Insulating chimney

Although I have insulated our attic, we still have an ice-dam problem. The roof area around the chimney seems to be most affected. Could it be that heat is radiating into the attic from the brick chimney (which comes up through the attic)? If so, how might I go about insulating that chimney? Would I need a vapour barrier too? Thank you.

It is probably the chase around the chimney that is allowing heat into the attic that is causing the ice dam problems. Look at the framing on your attic floor around the chimney. Usually the framing is separated around the chimney about two inches. This is a well documented area for what is known as an attic bypass, which is a major cause for ice dams.

This separation is there because of possible movement usually caused by live loads applied to the roof. What this means is you have to use something flexible to seal the gap between the attic floor framing and the chimney. My personal choice is foam pipe insulation and silcone caulking. I stuff the foam pipe insulation between the framing and the chimney and then caulk between the pipe insulation and the framing and chimney.

Thanks a million. I'll try that. Never would I have thought of it myself!