What to Look for when Buying a Flexible Chimney Liner

Flexible chimney liners are stainless steel cylindrical tubes that reside inside a masonry chimney. These steel tubes are inserted into a masonry chimney, often within the existing flue. A flexible chimney liner is used most often with masonry chimneys that have several bends or even imperfections in them and that are not completely straight. Most flexible chimney liners come in a wide range of sizes to fit your fireplace or fireplace insert.

A chimney liner, or flue, is very important in the construction of your fireplace since it is the innermost portion of a masonry chimney that funnels smoke away from the heating source. For a chimney liner to work properly, it must be free from holes, cracks, or any other kind of damage. If the liner is not completely intact it can allow the products of combustion, such as carbon monoxide, moisture, smoke or creosote to seep into the living spaces of the home. Sometimes the heat from the fireplace poses an additional fire risk to combustible materials near the flue such as framing, walls, ceilings, insulation, and even floors.

Characteristics of a Good Chimney Liner

One of the most important reasons to buy a good flexible chimney liner is to create an additional barrier between a chimney fire and your family. As chimneys age, they do begin to deteriorate and threaten the safety of the home. A flexible chimney liner also allows for easier cleaning of the chimney and extends the life of your masonry chimney.

High-efficiency furnaces that are found in recent renovations and new homes vent acidic moisture into chimneys. Over time this moisture can destroy a masonry chimney. A white film on the chimney’s bricks is a sure tell sign of excess moisture in the masonry chimney. If you notice this white film, invest in a good flexible chimney liner to prevent any damage to your home.

What to Look For in a Flexible Chimney Liner

Most flexible chimney liners are made of stainless steel alloy. Aluminum liners are used for low-efficiency gas furnaces. Terracotta is the overall best chimney liner, but it is very labor intensive and costly to install. A terracotta liner can last up to 75 years compared to a stainless steel liner that has a life expectancy of 25 years. An average cost for stainless steel flexible chimney liners is $20 to $40 per foot, which makes them a reasonable choice when replacing or adding a chimney liner to your existing masonry chimney.

When purchasing your flexible chimney liner, look for the widest liner possible. The wider the chimney liner, the better the draw or draft for the overall functioning of the fireplace. Once installed the liner should be insulated. Proper insulation allows the liner to heat up correctly and allows for a good draft and overall heating of the home. Insulation could be organic vermiculite or even a concrete insulation mixture that is poured down the flue to fill the extra space between the chimney liner and the flue.