The chimney or flue liner is arguably the most important safety component that when installed and properly maintained prevents the intense heat, burning embers and dangerous gases of a burning fireplace from entering your living space. In laboratory tests, it took less than four hours for nearby wood materials to catch fire from the intense heat of an unlined chimney, according to the Chimney Safety Institute of America (CSIA).
1. What does a chimney liner do?
The chimney or flue liner is a device that fits inside the chimney. Its main purpose is to insulate the chimney to prevent the high intensity of heat, fume and sparks of a burning fireplace from reaching the frame, siding and other combustible materials that can start a fire. It also helps prevent smoke, soot and toxic gases including carbon monoxide from seeping through the chimney masonry and into your home.
2. Why does my chimney need a new liner?
When the chimney liner is damaged beyond repair or has been incorrectly installed a certified chimney sweep will recommend it be replaced. Also, clay tile liners are among the most popular types of liners installed in homes. But they have a 50-year life expectancy; so if you’re home is over 30 years old your chimney liner may have deteriorated beyond its effectiveness or has simply reached its end of life.
3. Can a chimney liner be repaired?
Depending on the type of chimney liner, i.e., clay or cement, it may be repairable if the damage is minor like repairing a small crack, replacing one or two broken clay tiles or reinforcing a few mortar joints. Beyond that, the cost of repairing may exceed the cost of a new chimney liner. Steel liners that have corroded cannot be repaired.
4. What types of chimney liners are available?
There are three types of chimney liners:
Cast-in-place: A specially formulated cement-like mixture with ceramic properties is pumped into the chimney that when dried provides both insulation from extreme heat and toxic fumes and structural support. It is often recommended for older chimneys.
Clay tiles: Similar to a traditional brick and mortar process, individual pre-formed clay tiles are joined together with mortar to form an insulating liner in the flue to protect the chimney.
Metal: A stainless steel or aluminum tube-like structure with additional insulation material is cut to the chimney’s specifications and inserted directly into the flue.
5. How much does it cost to replace a chimney liner?
The cost depends on a variety of factors such as size, shape and condition of the chimney and the type of liner material. Stainless steel liners are often considered the most cost-effective option due to its lifetime warranty and lower cost of installation. Clay tiles have a low material cost, but its higher installation cost makes it a more costly option.
6. What happens if I don’t replace a damaged chimney liner?
Failure to replace a damaged chimney liner increases the risk of a chimney fire and exposure to carbon monoxide poisoning. It will also accelerate the deterioration of the masonry leading to more costly chimney repairs.
7. How do I know that I really need a new chimney liner?
Once the visual chimney inspection is complete, your certified chimney sweep will show you the video or digital images that were taken to document the condition of the chimney liner. This will help you understand the reasons for recommending a new liner.
