All you need to know about chimney liners

Winter evenings are the perfect time of the year to curl up on your favorite chair by the fireplace with a warm drink and your favorite book. To be able to enjoy these simple pleasures, it is important to ensure the fireplace and chimney are in perfect working condition, irrespective of whether you use solid fuels like wood, pellets, and coal, or gas. However, a lot of homeowners, especially those that live in older homes, are often unaware of how to maintain their chimney flues and how what role chimney liners play in the grand scheme of things. This short read will tell you all you need to know about chimney liners.

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What is a chimney liner?

A chimney liner, or flue liner, is a conduit made of metal, clay, or ceramic that is installed inside of a chimney. The main purpose of a chimney liner is to protect the inside walls of a masonry chimney from heat and corrosion while safely containing the byproducts of the fire, such as soot, gases, and smoke, and directing them to the atmosphere outside.

Building codes across the US recommend and in most parts, mandate the installation of flue liners in chimneys.

What are the main functions of a chimney liner?

Chimney liners are essential to any home that has a fireplace. They serve three main functions. These are:

Protection from fire

A lot of older homes often have woodwork alongside masonry near the chimney, such as rafters. Unlined chimneys are hazardous because they allow heat to travel through them at such a fast pace that using the chimney for three and a half hours is enough for the woodwork to catch fire. Chimney liners can prevent this from happening.

Protection of masonry

Unlined chimney pipes allow flue gases to penetrate the brick and mortar. These gases are acidic and can eat away at the mortar joints. This causes two types of damage. Not only does it lower the shelf life of the chimney itself by weakening the structure, but it also poses a serious health hazard by letting lethal gases like carbon monoxide leak into the home’s living areas.

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Efficient working of appliances

To function efficiently, modern chimneys need flue liners of the right size. The chimney is not only responsible for drawing out gases and smoke, but it is also equally responsible for letting in much-needed air for combustion. Wrongly sized chimney liners can lead to the build-up of creosote in wood-burning chimneys, and encourage the production of carbon monoxide in gas burners.

How long do chimney liners last?

Most experts agree that the average shelf life of a chimney liner is between 15-20 years. That is while making sure you get your chimney inspected by a professional at least once a year and conducted maintenance activities even more regularly. It is advisable to change the entire liner after 20 years to ensure your home is up to code and not at risk of a major fire. 

Read more: What is placed around chimney to prevent leaks

What are the different types of chimney liners?

There are three main types of chimney liners. They are:

Clay tile liners

Clay tiles are the most commonly used type of masonry liner. These are best suited for well-maintained open fireplaces chimneys.

Advantages

1. Chimney tiles are popular because they are easily available.
2. These are among the most inexpensive options for chimney liners.

Disadvantages

1. Clay liners aren’t built to handle chimney fires. Since they cannot quickly absorb and evenly distribute what is generated by a chimney fire, the tiles tend to crack and break apart. 
2. Clay flue tiles are also incapable of adequately containing the liquid combustion byproducts generated by modern gas fireplaces.

Metal chimney liners

Aluminum and stainless steel chimney liners are the popular choices when it comes to metal chimney liners. Stainless steel liners give you the option of choosing flexible liners and rigid liners as well.

Advantages

1. If properly installed, metal chimney liners are extremely durable and safe. 
2. While stainless steel liners are ideal for all chimney systems, aluminum liners are ideal for gas-burning fireplaces.

Disadvantages

1. Metal chimney liners are a lot more expensive than clay tiles.
2. Installation of metal liners will also incur the additional cost of high-temperature insulation to be installed with these liners for optimum performance.

Cast-in-place chimney liners

Cast-in-place flue liners are made of cement-like, lightweight products that, when installed inside a chimney, for a seamless, smooth, and insulated passage for gases. 

Advantages

1. They are extremely durable, which when installed properly, can last for as many as 50 years. That’s like getting a lifetime warranty.
2. They add to the structural integrity of older chimney walls.
3. These are suitable for fireplaces that use any kind of fuel.

Disadvantages

1. Cast-in-place liners aren’t very easy to install.
2. They are quite expensive. Expect to spend anywhere between $2,000 to $7,000 on materials and installation.

Read more: Inside fireplace painting

Written by Narayan Shrouthy. November 25, 2021

Narayan is a content writer for Kukun. With experience in both content writing and editing, Narayan mixes his writing and love for reading with his passion for music. As an active musician, He aims to be a key player in Kukun's content experience.

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barbara.smith.lgtb@gmail.com(@barbara-smith-lgtbgmail-com)

Ok, now I want this in my chimney. Thanks for making me think about how unsafe my hundred-year-old chimney is hahaha