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How Do I Know When To Replace My Chimney Liner?

chimney liner repair in Ewing NJAccording to the Chimney Safety Institute of America, tests show that heat moves rapidly through unlined chimneys, putting them at a much higher risk of fire and combustion-related damage. Many modern building and fire codes now mandate the installation of a chimney liner because of rising concerns over safety and performance.

However, many people neglect annual chimney maintenance, causing the liner to fall into disrepair and putting them at risk. So, what are the signs that your chimney liner needs replacing? If you can’t remember the last time you hired a professional chimney service company for maintenance and repair, call the experts at Mercer County Chimney Service.

What is a Chimney Liner?

As mentioned, a chimney liner fits inside the chimney to protect the brick and adjacent woodwork from heat and combustion-related damage. Chimney liners typically come in three materials.


The most common chimney liner is constructed from clay tiles. Clay is inexpensive and readily available, making it an economical option for many homeowners. However, while clay is the most common, it has drawbacks, including its inability to absorb heat as rapidly as other materials, which can cause the tiles to crack. Another disadvantage is that clay can’t contain the liquid combustion byproducts of today’s gas appliances, such as a gas-powered fireplace.


Metal chimney liners are stainless steel or aluminum and are more durable than clay and absorb and dissipate heat more quickly and evenly. Also, stainless steel is compatible with wood-burning and gas fireplaces, while aluminum is best suited for gas.


Cast-in-place liners are lightweight cement-like liners that form a smooth, well-insulated conduit to move the hot gasses from the chimney and expel them outside. The cast-in-place liner is ideal for old chimneys because it shores up the structure and is suitable for all fuels. However, the most significant drawback is the cost, as it’s the most expensive of the three. Also, cast-in-place liners can be difficult to install, and not every contractor has the experience to do the job safely and effectively.

What Causes Chimney Liner Damage?

A damaged chimney liner increases the risk of a chimney fire, so it’s crucial to keep them well-maintained and to repair minor issues before they escalate. Common causes of chimney liner damage are:

  • Poor construction
  • Faulty installation
  • Deterioration from the byproducts of combustion, which weaken mortar joints
  • Moisture and creosote buildup, which causes rapid deterioration

Unfortunately, it’s not always apparent that your chimney liner is damaged; however, there are some red flags to watch for. Suppose you notice your fireplace is in overall poor condition, or you can’t remember the last time you called a chimney service for inspection and maintenance. In that case, it’s safe to assume your chimney liner has suffered some damage.

Also, pay attention to the chimney’s structure for damage. Lastly, if you find bits of the lining material in your firebox, you must replace the liner as soon as possible. This is most common with clay liners, as they deteriorate more rapidly than metal or cast-in-place liners.

How Long Should My Chimney Liner Last?

Many factors contribute to a chimney liner’s lifespan, including the material it’s made of, your fireplace usage habits, and the environment. The average lifespan of a chimney liner is 15-20 years, and once your liner reaches that point, it’s due for replacing. However, some factors can add or subtract how long your chimney liner will last.

  • Clay liners are the most common and inexpensive, but they don’t absorb and distribute heat as effectively as other materials, causing them to deteriorate more rapidly. Depending on your maintenance schedule and usage habits, a clay liner can last five to 15 years.
  • Metal liners are more robust than clay. They’re lightweight and more efficient at absorbing and distributing heat, making them more durable. Again, their lifespan depends on routine maintenance and usage, but it’s common for metal chimney liners to last up to 25 years.
  • Cast-in-place liners are the most robust because they’re typically constructed from cement, and with proper care, you can get up to 50 years from a cast-in-place liner.

How Can I Know When to Replace My Chimney Liner?

Now that you know the importance of a chimney liner, let’s look at the most common signs saying it’s time to replace it.

You’ve Purchased a New Heating System

As mentioned earlier, not every chimney liner is compatible with every fuel type. So, if you’ve upgraded to a system that uses a different fuel source, from wood to gas or oil, for example, your current liner may not provide the proper ventilation required to keep you safe.

You’ve Neglected Your Chimney

Many homeowners focus solely on the fireplace or heating stove and ignore the chimney, even though it’s a crucial part of the system. If it’s been years since your last chimney inspection, or you can’t remember when you last had one, there’s a good chance your chimney liner is damaged and needs repairing or replacing.

Venting Problems

Chimney liner damage isn’t always the cause of fireplace venting issues, but it’s something you’ll want to check if you experience venting problems, such as

  • Smoke spilling back into the house instead of going up the chimney
  • Difficulty lighting a fire
  • A fire that requires constant fuel to stay lit
  • The fire roars because of a rush of air coming into the flue

Regardless of the cause, if you experience any of these issues, call a certified chimney specialist for immediate inspection to protect your family and property against fire damage.

Tips to Protect Your Chimney

Having a fireplace is an excellent way to provide heat and enhance the ambiance and value of your home. However, fireplaces, wood stoves, and oil-burning heaters can be dangerous if they’re not well-maintained and respected. You can ensure your chimney runs efficiently and safely by following these simple tips.

Only Use Firewood

If your fireplace burns wood as the fuel source, it’s imperative that you only use wood to burn. Fireplaces aren’t garbage disposals, so don’t burn furniture, cardboard, packing materials, magazines, clothing, or garbage because they can cause the fire to burn too hot, which can damage your chimney and cause it to deteriorate more rapidly.

Don’t Use Accelerants

Again, if you use a wood-burning fireplace or stove, use matches, logs, and kindling to start the fire and nothing else. Many people become frustrated if the fire doesn’t start as quickly as they want and resort to using lighter fuel, kerosene, or another accelerant. Using these products can generate too much heat for the system to handle.

Use Dry Wood

Dry wood burns more efficiently than damp wood, creating less smoke and a healthier fire.

cleaning the fireplace, hightstown njCall a Certified Chimney Specialist for Annual Inspection

By far, the best way to ensure that your chimney runs safely and efficiently is to hire a professional chimney service, like Mercer County Chimney Service, for yearly inspections and maintenance. Routine maintenance keeps creosote from building up and allows you to find and repair minor issues before they escalate into problems requiring expensive and labor-intensive repairs.

Chimney maintenance isn’t a household chore you want to ignore because doing so puts your family and your valuable property at risk. Mercer Chimney Service is a fully licensed and certified chimney service company for all of your chimney repair and maintenance needs. Whether you need chimney repairs, chimney liners, chimney cleaning, chimney crowns, or chimney inspection, you can count on our experienced professionals.

We’re located in Hamilton, NJ, and serve all of Mercer County.

Call us today to book an appointment at (609) 802-5288 or contact us online.