The 4 Main Causes of Chimney Damage & Chimney Fires

Chimneys can suffer damage in several different ways – some that are preventable, some that aren’t. Let’s look at both kinds and talk about how you should address them.

Chimney Masonry Repair Amherst, NHPoor workmanship in building the chimney

If defects were built into the chimney when it was constructed, damage at some level down the line is likely. Common problems include:

Wrong-size flue for the fireplace that results in unsafe drafting

Inferior bricks and mortar that are susceptible to faster decay

Unparged smoke chamber

Faulty liner installation

Footing that is too narrow or too shallow and leads to a tilting chimney


These and other similar problems often aren’t revealed until trouble arises. The best way to evaluate the condition of your chimney is through a certified inspection performed once a year. This way, you can address problems early and reduce the likelihood of many different major repair or rebuilding projects down the line.

Weather or seismic events

As strong and sturdy as chimneys are, they often can’t withstand a lightning strike, earthquake, gale-force winds or pounding hail storms – especially true for chimneys that are getting up there in age.

Following any of these events, you may be able to visually tell that damage has been done to the chimney. However, there could be very minor damage that’s not easy to see but that could turn into a serious problem. For this reason, it’s recommended that you schedule a chimney inspection after any major weather or seismic event, just to make sure.

Chimney With White StainsChimney leaks

A leaky chimney can be caused by the events listed above as well as by small cracks in the masonry that naturally happen over time. When water is able to infiltrate these cracks, it will begin a process of decay, particularly when the temperature drops and the water freezes and expands.

The first step in addressing a chimney leak is a professional inspection to determine the extent of the problem. Solutions may include a waterproof sealant on the masonry or a process called tuckpointing, where missing sections of mortar are replaced with a strong new application. Caught early, a chimney leak can be fixed simply enough. If left unaddressed, it can lead to large-scale structural damage.





Signs there is a chimney leak or may be one soon:

  • Cracks in the chimney crown
  • Severely damaged chimney cap
  • Warped or missing roof flashing
  • Crumbling or loose bricks and mortar
  • Water in the firebox
  • Damp sections of walls and the ceiling near the fireplace
  • Strong musty odors coming from the firebox
  • White staining on the exterior chimney masonry

Chimney Fires

Excess flammable creosote in the flue is the primary cause of chimney fires, which can be large or small but always potentially destructive. Annual chimney sweep service is the solution. Chimney sweeps use specialized tools to safely remove creosote buildups and dramatically reduce the likelihood of a chimney fire.

Over time, chimney fires can destroy the chimney liner, eat away at the chimney’s masonry and put vulnerable materials of the home at risk of a devastating fire. You can’t keep creosote from forming if your fireplace burns wood, but you can keep your chimney clean and safe.

Black Moose Chimney & Stove of Antrim, NH, is on call to help with all your chimney needs including CSIA-certified chimney cleaning, chimney inspection and chimney repair services. Let us help you keep your chimney safe and working correctly. Schedule an appointment or get your questions answered at (603) 525-7905.