As solidly built as chimneys are, they need a number of components to keep them working safely and efficiently. Let’s look at some of these chimney components and find out what they do and why it’s important.
The flue, often just called the “chimney,” is the vertical interior passage that allows smoke to move up and away from the fireplace. A sturdy flue serves as a protector for nearby combustible materials of the home by containing intense heat and toxic gasses.
Flues are commonly constructed of brick and mortar (masonry) and hold up well for many years. Eventually, however, cracks in the masonry can begin letting water into the system, where it will start a cycle of decay until the flue is no longer safe to operate. Leaky chimneys need prompt professional attention.
Chimney liners are built or installed on the inside of the flue to add even more protection to the home. Liners can be made of metal, clay tiles or a poured-in-place compound. As with the chimney’s masonry, if cracks appear in the liner, heat and gasses can escape and cause damage.
Assessing the condition of a chimney liner normally requires the services of a certified chimney inspector, who will use various tools including video technology to look at all the surfaces of the liner.
Flashing is the metal strips that block the gap between the external chimney masonry and the roof. Without a layer of flashing, rainwater and water from melting snow can run down into the home and cause rotting and decay to walls, insulation and other structural components.
Incoming water also can begin to harm the exterior masonry of the chimney in areas the average person can’t see. Flashing is one of the easiest ways to prevent some very expensive damage.
The chimney crown is the cement layer that seals off everything at the top of the chimney except for the flue pipes. Like the chimney cap, the crown shields the flue from water and moisture. Crowns usually are beveled to allow water to run away from the flue opening.
Cracks in chimney crowns can happen after years of use. If caught early, the cracks can be sealed to prevent further damage. In some cases, a crown will have to be rebuilt.
Located just above the firebox, the damper is open when a fire is burning to allow a smooth path for smoke and toxins to leave the home. A damper that won’t fully open can cause smoke and dangerous carbon monoxide to back up into the home.
After many years of service, dampers can become rusted and warped, making it impossible to close them completely when the fireplace isn’t in use. Damaged dampers can be repaired or replaced.
The chimney cap sits atop the chimney and provides protection against incoming rain and snow as well as debris such as leaves, twigs and small-animal nests.
A good chimney cap also acts as a barrier to keep shooting sparks and embers from flying out the top of the chimney and landing on the roof or in the yard. Damaged chimney caps can either be replaced or repaired.
High’s Chimney Service of Gaithersburg, MD, is here to help keep all your chimney components and your chimney itself in excellent working condition. We provide a full menu of chimney cleaning, chimney repair, component installation and chimney inspection services. Learn more or schedule an appointment by calling (301) 519-3500.