Why fireplace safety and cleaning your chimney matter

Why You Must Clean Your Chimney

Wood fires do not burn cleanly. When wood burns, it releases a host of contaminants that coat the inside of the chimney. Creosote, an oily, black substance, is one byproduct of wood-burning fires. Creosote forms as a result of gases that have not fully combusted, and it condenses on the inside of the chimney and remains until removed. Burning green or unseasoned wood hastens creosote build-up. 

Also, organic, flammable debris can enter the chimney, brought by the elements or by animals. Wind can deposit leaves and twigs in chimneys lacking flue caps. Birds and vermin can nest in chimneys or otherwise bring unwanted materials.

Chimney fires begin with snaps and pops as loud as gunshots, progressing to a deep, rumbling sound. Oily, black, flaming creosote rains down into the firebox. When the fire starts, it starts like an explosion. Flames blast out of the top of the chimney and back down into the firebox. Due to thermal expansion, the flue may crack at some unreachable mid-point and shoot flames into the walls from the inside. Chimney fires typically cannot be controlled by the homeowner. Because firefighters have to shoot water from the top downward, the house suffers damage from flooding. In many cases, the entire house is lost.

When to Clean Your Chimney

Chimneys should be cleaned no later than the early fall, before fire burning season. If you choose to hire a chimney sweep, you can expect a quick turnaround if you have them come earlier, ideally in the summer. For self-cleaning, late summer is the best time, since you can count on a dry, safe roof and mild conditions. 

In addition to scheduled chimney cleanings, you should clean when any of these conditions are present: