Masonry Chimney Construction - Sandkuhl
2. Place and position 12"Ø x 6" starter flue liner, centering it directly over the outlet on top of the fireplace with the straight cut end down. Adhere starting flue liner to fireplace dome with refrac-tory mortar. 3. Place the next full 2' section of 12"Ø flue onto the starter flue.