Summer is well underway with the temperature and the humidity both in the 90s. Why would anyone want to think about woodstove and fireplace chimneys?

“Safety,” says John Kirby, Virginia Cooperative Extension specialist at Virginia State University. “When you burn wood for heat, the fire is not hot enough to consume all of the combustibles in the wood. The fire produces by-products that condense on the inner walls of the chimney. These condensed by-products form creosote, which is highly flammable, and is what fuels a chimney fire.”

When most people think of a chimney fire, they picture a violent explosion of flame and dense smoke that attracts the attention of neighbors as well as the home occupants. However, according to Kirby, it is possible to have a chimney fire and not even know it. “Slow-burning chimney fires don’t get enough fuel to be as dramatic or visible. Yet, the temperatures they reach are very high, around 2000 F, and can cause as much damage to the chimney and nearby combustible parts of the house as a more explosive chimney fire.”

Know the Signs of Chimney Danger

One chimney fire may not harm a home. A second can burn it down, according to Kirby. Even perfectly sound chimney can conduct enough heat to ignite nearby combustibles. When you hire a professional, Chimney Safety Institute of America (CSIA) certified chimney sweep, that person will not only clean the chimney but will inspect the whole fuel venting system for fire damage. The signs are:

  • “Puffy” creosote, with rainbow colored streaks, that has expanded beyond creosote’s normal form
  • Warped metal of the damper, metal smoke chamber, connector pipe, or factory-built metal chimney
  • Cracked or collapsed flue tiles or tiles with large chunks missing
  • Discolored and distorted rain cap
  • Creosote flakes and pieces found on the roof or ground
  • Roofing material damaged by hot creosote
  • Cracks in exterior masonry
  • Evidence of smoke escaping through mortar joints of masonry or tile liners

“If you did not have your chimney inspected after the heating season, now would be a good time,” Kirby explains. This is the slow season for most chimney sweeps, and you may even be able to get a discount. If you wait until the fall, you may find that the cold weather arrives before you can get the chimney inspected and cleaned.”

10,000 cases of carbon monoxide-related injuries are diagnosed each year. Because the symptoms of prolonged, low-level carbon monoxide poisoning mimic the symptoms of common winter ailments.