The round chimney pipe comes up from the basement all the way up to the attic, and through the roof where it is enclosed by square sheet metal. At one time there were bricks painted on the sheet metal to make it look like a brick chimney I guess. If I go into the attic and look down the chimney pipe towards the basement, I can see all the way down to the first floor. There is no insulation in there at all. If I look up the square chimney there is no insulation between the round pipe and square chimney going through the roof. What kind of insulation should I use to stop the air comimg from down below, and is there anything I can use to insulate the pipe and chimney since this is where a lot of the frost is concentrated?