Chimney Liners: Description, Types, and Importance


At High’s Chimney we’ve found that chimney liners are perhaps the most under-appreciated part of the fireplace and flue system. That’s why we decided to write a little piece giving an overview of their function and importance.

What is a Chimney Liner

A chimney exists to carry dangerous gasses out of the home, and it needs to do so without getting over-heated. A chimney liner creates a barrier between the flue and the walls of the chimney, and its purpose is to insulate and protect the chimney. According to the Chimney Safety Institute of America, a chimney liner is defined as:

“A clay, ceramic, or metal conduit installed inside of a chimney, intended to contain the combustion products, direct them to the outside atmosphere, and protect the chimney walls from heat and corrosion.”

There are 3 Types of Chimney Liners

clay tile chimney liner

Clay Tile Chimney Liner – Clay liners used to be the most popular liner and are found in old homes. They usually last a while in a properly finished chimney. However, they don’t offer maximum containment and protection if a chimney fire does occur. Also, it is very difficult to repair or reline a chimney with clay tile.

 

Cast In Place Chimney Liner
Cast in Place Chimney Liner – These liners were created 60 years ago and were quite popular for a while. The benefit of the cast-in-place liner is that it insulates very well and keeps the chimney cleaner. However, with these liners, installation and relining is very costly, especially if the chimney has any curves or bends.

 

Relining Chimney with Metal Liner

Metal Chimney Liner – The most popular chimney liner in modern construction, metal liners come in many different sizes and shapes. Metal chimney liners are relatively easy and inexpensive to install, and they generally last quite a while.

 

Why Chimney Liners Are Important

We’ve got a whole list of reasons why chimney linings are so important:

  • Unlined chimneys may leak harmful gases like carbon monoxide into the living space.
  • If you have gas appliances that vent through your chimney, the low-temperature flue gasses from modern appliances produce huge amounts of condensation. In an unlined chimney, the condensation may increase masonry deterioration and may leak into the house.
  • If the chimney is used for wood burning, condensation can help form tar and creosote. These byproducts are flammable. Combating condensation is one way a liner reduces the chance of fire.
  • A lined chimney does not get as hot as an unlined chimney, and has less chance of chimney fire.
  • Lined chimneys are more energy efficient, due to enhanced air flow and better heat retention.
  • Unlined chimneys require more wood or fuel.
  • Just because you have a chimney liner, this doesn’t mean it offers maximum protection and benefits. The liner must be the right size. Also, chimney liners do get damaged and do deteriorate over time.
  • Most building code standards require a chimney liner.
  • Some homeowners’ insurance policies limit coverage for certain events if you make changes without improving the chimney.
  • Some homeowners’ insurance policies will pay for relining a chimney in certain cases, due to the protection it brings.

In summary, a chimney liner is a very important form of protection for your chimney and your home, and you should exercise diligence in ensuring you have a healthy, fully-functioning liner that is right for your chimney and home.

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