Over two fire seasons, we inspected chimneys across Bergen, Morris, Essex, Monmouth, and Ocean counties in New Jersey. The numbers were worse than expected: 4 out of 10 chimneys we inspected had damage that represented a real risk in the coming heating season. The most dangerous conditions were also the most invisible from outside the home.
The Most Dangerous Finding: Cracked Flue Liners
Cracked or separated flue liner sections were present in 22% of the chimneys we inspected in New Jersey. The flue liner — the clay tile or stainless steel lining inside the chimney — is the only barrier between combustion gases and the surrounding masonry and wood framing of the home. A cracked liner allows heat, carbon monoxide, and sparks to penetrate the chimney structure. This is the condition most directly associated with chimney fires and carbon monoxide intrusion in NJ homes. It's also invisible from the ground — it requires a level 2 inspection with camera equipment to identify.
The Second Most Common Dangerous Finding: Failed Chimney Crowns
The chimney crown is the concrete or mortar slab that seals the top of the chimney around the flue. In New Jersey's freeze-thaw climate — particularly in North Jersey and the highlands — crowns crack from water expansion and contraction. A failed crown allows water to enter the chimney system directly, accelerating deterioration of the flue liner and mortar joints and creating the conditions for interior water damage. Chimney crown repair in NJ is one of the most cost-effective preventive repairs available — typically $280–$450 — and prevents thousands in subsequent water damage repairs.
Mortar Joint Failure
Deteriorated mortar joints between chimney bricks are the most visible sign of chimney damage in NJ homes and the most commonly deferred. Open mortar joints allow water infiltration that accelerates in freeze-thaw cycles — the water enters the joint, freezes, expands, and forces the joint wider. Tuckpointing — replacing failed mortar joints with fresh mortar — stops this cycle. A chimney that needs tuckpointing today needs rebuilding in 5–7 years without it.