Do You Have to Insulate a Flue Liner?

Rationale

• You should insulate your chimney flue liner for a number of different reasons, the first of which is safety related. Insulating the chimney flue liner will reduce the risk of fire by reducing the amount of tar and soot. The liner creates a smooth surface on the inside of your chimney flue, which prevents these substances from accumulating. Accumulating tar tends to fall back into the fire, where it can be burned up and released back into the air in vapor form.

Leaks

• A chimney flue liner also will prevent potentially dangerous leaks of smoke, tar and other types of gasses from your fireplace through cracks in the chimney.

Flue Gases

• Flue gases are contained better when a flue liner is present. Flue gases cool faster in larger chimneys. Although the cooled flue gases are less dangerous than those that retain their high temperatures and remain behind in the fireplace or chimney, the quickly cooled gases also can create greater levels of condensate. An insulated liner will prevent the accumulate of condensate as a result. The reduction of these deposits also will help the fireplace maintain its flue gas velocity flow.

Installation

• Two basic types of insulation can be used for the chimney flue liner. On one hand, chimney flue liners can be insulated by using a blanket wrap, which simply is placed around and clamped down on the liner before it is put in place. The second option is to use an insulating mix that can mixed in a wheelbarrow and spread around the outside of the liner, much like spreading cement or mortar on another type of surface.