How Chimney Liner Affects Chimney Masonry

Chimney liners can be made from several different materials and are installed or built on the inside of a standard chimney. Damage within a chimney liner can lead to some serious problems, affecting not only the chimney masonry but also the home and the air quality within it. Ye Olde Brit Chimney Sweep of San Bernardino, CA, would like to share some important information you should know about chimney liners and chimney masonry.

Chimney liner snapshot

As mentioned, liners can be made of various materials, including:

• Stainless steel
• Clay tiles
• A poured-in-place compound

Liners must be sized correctly in order to allow a proper draft to remove smoke and harmful toxins from your fireplace.
Homes built before the mid-1900s often didn’t have liners in their chimneys. Today, the law requires that all chimneys be built with liners.

How chimney liners become damaged

Your chimney liner protects the vulnerable masonry of your chimney when the fireplace is in use. A damaged liner will not provide this protection. Liners can become damaged in several ways:

• Repeated chimney fires, both large and small
• Acids in creosote, which forms during wood combustion
• Years of water wear caused by a leaky chimney
• Inferior liner materials
• Improper installation of the liner

Specific concerns for the chimney masonry

When there are breaks or decayed areas in a chimney liner, the masonry of the chimney is immediately vulnerable. Tests performed by the National Bureau of Standards (NBS) showed that flue gases can easily get into the pores and any cracks in the masonry. This intrusion will shorten the masonry’s lifespan.

Flue gases and creosote deposits are both acidic. With a damaged liner, the acids that are a normal part of combustion can begin eating away at bricks and mortar joints. When this happens, a chimney can start to lean to one side and eventually collapse entirely.

Other concerns with a damaged chimney liner

Aside from negatively affecting the chimney masonry, a damaged chimney liner can also lead to a leakage of carbon monoxide. This gas is present in smoke and cannot be smelled or seen. Carbon monoxide poisoning can happen before you know it, and in the worst case, it can be fatal. Cracks or breaks in a chimney liner will allow ever-greater buildups of creosote to form inside the flue. These buildups narrow the flue passage and prevent proper drafting, which can lead to the backup of smoke and toxic gases.

Incorrectly installed liners

If someone other than a chimney and venting professional installed your chimney liner, it’s possible that the wrong size was used. Liners must be sized specifically to draft the appliances to which they’re connected. If the size is wrong, the fireplace will not draft efficiently, and some of the problems mentioned above can result.

Have your chimney liner inspected

Experienced chimney inspectors can quickly tell you if a faulty chimney liner is causing damage to the surrounding masonry. He or she can also determine if problems with the liner are leading to drafting and other issues. Chimneys should be inspected once a year so that trouble can be fixed before it gets out of hand. For more than 30 years, Ye Olde Brit has been helping our San Bernardino-area customers solve problems caused by their chimney liners. We provide complete inspections, repairs, chimney cleaning and relining services. Speak with a chimney expert today at (909) 880-2120 or reach out using our handy contact form.