Why are Chimney Liners Necessary?
Chimney liners began to be a requirement in about the 1950s, which researchers believe is one of the reasons the number of homes with fireplaces began to decline significantly in the U.S., though their popularity has been on the rise again for many years. A chimney liner is the most important safety feature of a fireplace and chimney because it prevents house fires. The more you understand about the operation and anatomy of a chimney, the more a flue liner makes sense.
The function of a chimney is to provide an exit point for combustion materials such as smoke and soot. The draft in a chimney works best when there is a straight, smooth, and warm interior. The chimney liner smooths out the rough masonry walls and expels combustion byproducts more efficiently. A healthy draft produces a cleaner burning fire and means there is less smoke that spills into the home.
The temperatures inside a chimney are extreme, and it’s important to protect nearby combustible materials from being exposed to the heat. When connecting ceilings, roofs, and walls are exposed to heat inside a chimney, they can burst into flames, igniting a quick-burning house fire. A chimney liner protects these materials; but if there is even a small crack in the liner, the potential for a house fire is significant.
At some point in time, it becomes necessary to replace a chimney liner. There are three kinds of chimney liners to choose from when building a new home or replacing a damaged liner, each of which has unique benefits: clay tile liner, cast-in-place liner, and metal flue liner.
Cast-in-place chimney liners are less expensive options than clay tile liners. The mortar used to create cast-in-place liners offers numerous benefits. The material:
- Provides excellent insulation that protects combustibles;
- Is able to withstand extremely high temperatures;
- Increases the structural integrity of the chimney;
- Reduces creosote buildup; and
- Is as durable as clay tile liners.
Installing a cast-in-place liner is not a do-it-yourself project. The mortar is poured down the chimney with vibrating bell-shaped pieces that shape the opening. This type of liner is the preferred method for chimneys in older homes, including historic homes.
Metal Flue Liner
Metal flue liners are the most versatile and are often the most affordable. The preferred material is stainless steel, though metal chimney liners come in a variety of alloys. Some of the liners are rigid and some are flexible. Installing insulation is an added step that is recommended when installing a metal flue liner.
Clay Tile Liner
When a new chimney is being built, clay tile liners are by far the top choice. Clay tiles are economical, highly durable, and capable of withstanding extreme temperatures, when installed properly. In fact, clay tiles usually last an average of 50 years before needing to be repaired or replaced.
Repairing damaged tiles is extremely labor intensive and for that reason is not a cost-effective approach, when it’s time for replacement of a damaged clay tile liner. In short, to replace a damaged clay tile liner, the walls of the chimney often need to be broken at various intervals. Specialized tools are used, and labor costs are very high.
When your chimney is inspected by our professional chimney technicians, you may be advised that your chimney liner is damaged. We will answer all of your questions and help you determine the best approach for restoring your chimney to safe condition.