Many people take their chimney for granted and don’t understand that it is more than just a tower of bricks that funnel smoke from your home. There aren’t a lot of moving parts, and to most people, that indicates that the only thing that can go wrong is if a moving part stops moving the way it’s supposed to.
The moving part people are most familiar with is the damper. The damper is what closes the cold from entering your home when it’s closed and it lets the smoke out of your home when it’s open. The other part you usually notice is the door in the firebox that allows the ash to flow down to the ash box.
But your chimney is what protects the inside of your home from fire, moisture, noxious fumes and smoke. But what is the flue and where is it? The flue is what provides the passage of smoke and gases from your fireplace or wood stove. It runs all the way to the top of your roof and rises above it. You call it a chimney but it is the flue. Flues can be lined or unlined, but unlined flues are extremely dangerous. There are a variety of linings for a flue but the most common are steel or ceramic flue tiles.
The part of your chimney that extends beyond your roof is constantly exposed to the elements. The exposure to heat, moisture and cold, in conjunction with the intense heat and corrosive sediments that are produced by fires in your fireplace, has a detrimental effect on the liner of your flue. It can cause cracks, flaking and gaps in the masonry that can allow gases and moisture to migrate from the inside of your flue into your home.
The gaps and cracks can cause your chimney bricks to loosen. It can cause your chimney to shift and to not stand straight. It can also cause your chimney bricks to fall and if left alone to further deteriorate can eventually cause your chimney to fall apart resulting in roof damage, falling bricks and the worst case scenario, a falling chimney.