During this chimney inspection we found that the fireclay flue liner was seriously damaged. This chimney is used to vent a wood stove.
The vertical cracks on these tiles indicate that a high temperature suddenly entered the flue system. If a flue tile heats too quickly with too high of a temperature it may crack. Burning cardboard in a stove or fireplace can one cause this issue. Another is a traditional chimney fire caused by a creosote filled chimney. If a chimney filled with creosote ignites a chimney fire will take over the chimney and may cause serious damage to the flue tiles. It may even lead to a structure fire.