2 Common Types Of Chimney Liners

Posted on: 30 June 2016

The liner is your chimney's first line of defense against the risk of fire. Unfortunately, many people fail to realize the importance of a liner--let alone that their chimney even has one! If you would like to learn more about this vital fireplace component, read on. This article will provide an overview of two of the most common types of chimney liner available today.

Liners In General

Regardless of the material they are made out of, all chimney liners serve one common purpose: reducing the chances of your fireplace leading to a house fire. They do this by providing a smooth, second layer to the inside of your chimney. This helps to absorb and diffuse the large amounts of heat contained in smoke, thus keeping the outer walls of the chimney--not to mention the adjacent portions of your home--at a safe temperature. Not only that, but a liner makes it less likely that burning ash or particulate matter will become stuck in the more irregular surface presented by brick. 

Clay Tile Liners

Clay tile chimney liners possess the distinction of being the oldest means of lining a chimney. As a result, they can be found in homes built over a wide period of time. The unique composition of clay allows it to stand up to even the highest temperatures without suffering cracks, chips, or other forms of damage. It also possesses a high degree of resistance to the corrosion causing substances contained in smoke.

Chimney liners made of clay tile are the least expensive option when it comes to building a new chimney. That's because they are purchased in pre-formed segments that are then mortared together by a trained professional. Unfortunately, this installation method tends to work against them when being considered as an option for replacing a preexisting liner. In that case, the difficulty of joining the segments together inside of a chimney makes the process more expensive than some of the alternatives.

Cast-in-place Liners

Unlike clay tile, cast-in-place liners are constructed on-site, according to the dimensions and quirks of a specific chimney. First, however, the aging or damaged liner must be thoroughly removed. Once the chimney has been stripped down to its bare brick exterior, a temporary flue former is installed from above. This flue former, composed of an inflated rubber bladder, is positioned where the eventual air passageway will be.

Once the former is in place, mortar mix is carefully poured down the chimney around it. When the mortar has cured partway, the former is uninflated are removed. The resulting liner has the advantage of sitting flush against the chimney walls. This provides a greater measure of insulation. Because less heat escapes past a cast-in-place liner, the fire below is able to burn hotter, thus producing less smoke and soot.

Cast-in-place liners are generally a more affordable option than clay tiles for replacing an old liner. That said, be prepared for the process to be somewhat loud and invasive. Between installing the flue former, hauling up a huge quantity of mortar, and breaking down all of the required installation equipment, there will be quite a lot of activity on your roof. Luckily, this inconvenience shouldn't last long, as the installation process is generally completed over the course of a single day. To learn more, contact a company like The Chimney Medic.