1. Creosote buildup can cause fires if not found first with a chimney inspection.

When you use your fireplace or wood-burning stove, by-products such as smoke, vapor, and unburned wood move from the hot fireplace or wood-burning stove into the cooler chimney. Condensation of wood-burning byproducts results in highly flammable creosote on the walls of your chimney liner. Creosote is mostly tar and is brown or black in color. The substance takes several dangerous forms. Since creosote is highly flammable, if the temperature in the flue is high enough, and the creosote layer on chimney walls is thick enough, the creosote can catch fire. That fire can damage the chimney, surrounding masonry, and the underlying structure of the house, or enter the home interior. In contrast, a chimney filled with build-up is a disaster waiting to happen. Clean chimneys don’t catch fire.

If you scratch a fingernail against your chimney walls and uncover dark buildup, it’s probably time to get the chimney inspected. As part of a chimney inspection, a chimney professional will identify whether there is excessive creosote buildup that warrants removal and, if needed, remove both creosote and soot to minimize fire risk. The technician can also repair or replace components that promote increased creosote buildup.

2. The chimney’s history may come back to haunt you.

In general, before selling a house or otherwise transferring it to new ownership, a chimney inspection should be performed. Rather than risk a chimney fire or the release of harmful vapors, get an inspection before your first use of the fireplace or wood-burning stove. An inspector can identify existing chimney vulnerabilities and address them before they do you and your home harm.

3. Parts you can’t see with the naked eye may be damaged.

Timely repair or replacement of damaged chimney components can minimize the risk of fires, carbon monoxide exposure, and water damage. Unfortunately, many vital parts of the chimney are hidden or too high to be visible for inspection by homeowners. A chimney sweep has the tools and training to assess damage for the following critical chimney components:

Masonry: If you have a masonry (e.g., brick) chimney, the porous material can easily expand or contract with heat or cold, and eventually form small cracks. These cracks can grow larger and jeopardize the structure of the chimney or let smoke and vapor in the flue slip indoors, especially if coupled with cracks in the flue liner. A pro can inspect the integrity of brick and mortar on chimneys and recommend necessary masonry repairs.

Crown: The crown is a downward-sloping concrete, stone, or metal overhang at the top of the chimney that diverts water away from the chimney exterior to prevent erosion. If cracked, usually as a result of weather exposure or the use of weak construction materials, rainwater can run down the sides of the chimney and erode it, compromising its structural integrity over time. Rainwater can also slip inside the flue and degrade the flue liner (see below). An inspector can repair or replace a cracked crown to stave off water damage to the chimney and flue.

Flue liner: The flue liner—a clay, ceramic, or metal conduit located between the flue and the chimney walls—protects chimney walls from heat and corrosion when by-products of fire are directed out through the flue. It also keeps smoke and harmful vapors like carbon monoxide from traveling through potential cracks in chimney masonry and entering your home. When cracks form in the flue because of excessive heat, water damage, or wear and tear, high heat or embers can damage chimney walls or touch surrounding combustible materials of the home and spark a chimney fire. Smoke and vapors can also travel through cracks in masonry and enter the home, potentially exposing you to carbon monoxide. An inspector can quickly spot cracks in the flue liner and repair them.

4. Obstructions invite harmful vapors indoors.

Everyday storms can deposit twigs, leaves, and other debris into the chimney. Likewise, critters such as birds, squirrels, and raccoons can build nests in chimneys. Any of these obstructions can block the flue and prevent the normal escape of fire by-products from the fireplace or wood-burning stove to the outdoors. The backed-up smoke and vapors in the chimney can then enter the home, potentially exposing you to carbon monoxide gas—which is an invisible, odorless, and lethal. The obstructions can also act as kindling, potentially sparking a fire if they come into contact with loose embers.

If you put a flashlight up the chimney flue and observe nests or debris, or have been hearing animal sounds from the chimney and suspect a nest, have a chimney sweep inspect your chimney for obstructions and, if needed, remove them. Some technicians can also install a chimney cap—a covering installed around the outside opening of the flue to keep out debris and animals.

5. Your homeowners insurance may not cover future damage otherwise.

Many homeowners policies require regular chimney inspections as a condition of compensating you for damages to the chimney caused by the use of a fireplace or wood-burning stove. This means that skipping inspections could force you to foot the bill in the event of future damage to your chimney. If, in reading your homeowners policy, you determine that chimney inspections are required to cover chimney damage, make it a priority to get your chimney inspected at the recommended intervals to avoid a gap in insurance coverage.