Flue tile cracks from thermal shock, a hot fire hitting a flue that was cold from disuse, more often than from simple old age. A fast, hot fire in a flue that has sat cold for weeks expands the clay tile unevenly, and repeated cycles like that eventually crack it.
Why this shows up more with occasional-use fireplaces
Counterintuitively, a fireplace used constantly through a real winter is gentler on its flue tile than one lit only occasionally for a cold snap and a cozy evening, exactly the pattern common in North Texas. A flue that is allowed to fully cool between uses, then hit with a roaring fire each time, goes through more thermal shock cycles per burn than one kept at a steadier temperature.
How we repair flue damage
Signs your flue needs a repair assessment
Frequently asked questions
Is flue repair the same thing as liner repair?
They overlap but are not identical. Flue repair addresses the structural clay tile passage itself; liner repair or relining addresses the material, clay tile or metal, that lines it. We will tell you exactly which applies to your situation.
How do you find a crack I cannot see from below?
A camera scope run the full length of the flue is the only reliable way. It is standard practice on a Level 2 inspection and something we can also run as a standalone check if you are not due for a full inspection.
Can I still use the fireplace with a known crack?
It depends on the size and location. We will give you a direct answer after seeing the scope footage rather than a blanket yes or no, since the risk varies a lot by how extensive the damage is.
Does a repaired flue need anything special afterward?
Just the same annual sweep and inspection as any flue. We will note the repair in your file so future inspections know exactly where to look first.