A chimney fire may not sound like much of a risk or much of a problem. After all, the chimney is well insulated. It may seem unlikely that the fire will get to the rest of the house if it even gets started in the first place. But dirty chimneys are susceptible to fires that, at their worst, can destroy homes and kill the inhabitants.
Chimney fires can catch on explosively, shooting flames and dense smoke out the top. Or they can be slow-burning and barely noticeable until they've gotten hot enough to damage the chimney irreparably and even catch your house on fire.
With a little care, chimney fires are easily preventable.
First, let's understand how chimney fires happen. The wood you burn sends smoke up your chimney. That much is obvious. But it may not be obvious that the smoke doesn't have to remain in a gaseous form. Wood smoke contains significant amounts of material that can condense on the sides of the chimney's interior. The result is a tar-like or flaky substance called creosote. Once it's formed, the creosote remains stuck to the inside of the chimney, just waiting for a flame or spark to reach up and set it off.