What to Look for when Buying a Clay Chimney Liner
Clay chimney liners insulate the interior flue of a chimney from the heat transferred by the fire or other heat sources. Unlined chimneys were recognized as a serious threat many years ago, and in as little as 3 hours, an unlined chimney can reach high enough heat to reach combustion. While chimney liners in general are referred to "clay chimney liners", there are actually three main types: clay, metal and concrete. The five factors listed below will help to determine what type of chimney liner is appropriate depending on the circumstances.
Chimney liners come primarily in three different types of materials: poured concrete, clay tiles and flexible or rigid steel liners. The installation for each type is very different. Which material you choose will depend primarily on what is appropriate for the type of fuel used, as some are not appropriate for certain types of fuel, such as a clay tiles with a gas stove.
Clay tile liners tend to be the least expensive of the three materials. Steel liners can be purchased in kits, decreasing the overall cost by saving on labor. There are an equal amount of sources that say it can be done by a do-it-yourselfer, as those that say to hire a professional installer. Concrete is relatively inexpensive; however the cost of the labor needed to properly install a poured concrete flue will offset any savings on the materials. The bottom line is to first determine what type of liner your will need based on the type of fuel your fireplace uses.
All three material types offer nearly the same lifespan. Some metal liners come with warranties that will likely outlast the ownership of the home, and can be transferred to a new owner. Generally, fifty years seems to be the average lifespan for all three types of liner materials.
Most chimney liners require installation by a professional. The only exception to this may be the steel chimney liner. Clay tile chimney liners can require very specific customization due to settling of the chimney, less-than-square corners, and the overall condition of the chimney. Poured concrete chimneys require a professional to pump the concrete into the correct form, but can be the best choice if the flue has bends or curves. Concrete can also help to reinforce the structure of an old chimney, giving additional stability.
5. Fuel Type
Clay tile chimney liners are unsuitable for gas fireplaces due to the vaporous nature of the byproduct of gas fireplaces. In the case of a gas fireplace, steel liners are the best bet, because they are impervious to the fumes that a gas fireplace emits. Clay tile chimney liners and poured concrete are most conducive for wood fireplaces, wood burning stoves and pellet stoves.
In all, chimney liners are an integral part of the chimney, furnace exhaust and fireplace in a home. Based on the potential ramifications (such as a house fire) of improper maintenance and attention, chimney liners should be left to professionals who are trained in the proper diagnostic and evaluation of the needs of the chimney.