Cracked Chimney Liner Repair

A Chimney Liner Plays an Important Role in Protecting Your Home from Fire and Dangerous Gases

By Mark J. Donovan

A cracked chimney liner can create a major risk to your home and family. If hot flue gases and/or fire penetrate through the cracked chimney flue liner, fire and unsafe gases could enter the home.

The typical masonry chimney includes a terra-cotta tiled chimney liner flue. The main purpose of the chimney liner is to direct the flow of hot gasses up and out of the chimney and into the atmosphere. A chimney liner also acts as a heat shield and a defense against chimney fires that can burn down homes.

Unfortunately terra-cotta tiled chimney liners often crack due to thermal shock caused by either chimney fires or simply dramatic changes in the chimney liner temperatures.

Often terra-cotta chimney liners crack near the top where they are exposed to much colder air. When a fireplace, wood stove, or furnace rapidly heat up a chimney liner, the dramatic change in temperature near the top of the chimney can cause the terra-cotta chimney liner to crack and flake.

A cracked chimney liner should be repaired as soon as possible if you plan to use the chimney. There are number of options on how to repair a cracked chimney liner. In some cases a terra-cotta chimney liner can be repaired by simply replacing the cracked flue tiles, if the cracks are limited to only the top of the chimney liner.

A mason can simply break up the top one or two broken terra-cotta tiles and replace them. However, the most they can replace is two tiles as they need to reach down and mortar the joint to properly make the repair.

An alternative cracked chimney liner repair is to install a cast-in-place chimney liner. With this type of chimney repair a long tubular inflated bladder is installed into the chimney and concrete is poured around it. After the concrete has cured the bladder is deflated and removed leaving a seamless flue.

The only concern with this type of cracked chimney liner repair is that if the new chimney liner is too narrow, hot gasses and smoke may end up backing up into the home due to the fact that they cannot be expelled quickly enough.

Probably the best cracked chimney liner repair option is to install a stainless steel liner. A stainless steel liner can consist of flexible or rigid tubing. Stainless steel chimney liners are relatively easy to install, and when installed properly are extremely safe. They are also easy to inspect and keep clean.

Stone chimney

In addition, stainless steel chimney liners can be used in a variety of applications such as with wood burning fireplaces and stoves, and gas and oil furnaces.

For information on Restoring Baseboard Heating Element Covers, see the Restoring Baseboard Heating Element Covers eBook from The Restoring Baseboard Heating Element Covers Ebook provides easy to understand, step-by-step instructions, on how to restore Baseboard Heating Element Covers so that they look new again. Pictures are included for every key step in the process.

For information on how to maximize a wood stove’s heating efficiency, see’s Installation of Hood over Wood Stove eBook

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