The inside of the chimney is not something most homeowners spend a lot of time thinking about, at least as long as everything appears to be working properly. But, chimney problems can begin long before you are aware of them and if you ignore them too long you could endanger your family’s health and safety. If you have any fuel burning appliance (a fireplace, wood stove, wood boiler, etc.) that vents up your chimney, you should have a chimney professional inspect your entire system at least once per year to be sure there are no problems developing that need your attention.
A properly designed and installed chimney liner should give you many years of trouble-free operation, but there may be situations that could require you to install a new chimney liner. Your chimney sweep will inspect your chimney system when he or she cleans it and will let you know if a new chimney liner is something you need to consider.
You will definitely need to install a new chimney liner if you live in a home that was built before World War II that has an unlined masonry chimney. Over time, weather and combustion products will degrade the bricks and mortar in your chimney and allow smoke and heat to enter your house. This can be a dangerous situation that could lead to carbon monoxide poisoning or a fire that ignites in the combustible structural materials in the vicinity of the chimney. If you go outside on a cold day when you are burning wood in your fireplace and you can see smoke seeping out from between your chimney’s bricks, you definitely need to install a chimney liner.
If your chimney was constructed with a built-in clay tile liner, you may not need to install a new chimney liner unless your inspector finds evidence of deterioration of the liner tiles or mortar between them. A properly constructed clay tile liner will last many years unless it is compromised by structural shifting or damage due to freeze/thaw cycles affecting the chimney.
You will need to install a new chimney liner if you decide to put a woodstove insert into your fireplace to improve your home’s energy efficiency. Most inserts require installation of a stainless steel liner inside the chimney flue that is properly sized for the application. In some cases, your installer may have to remove the clay tile liner to make room for the stainless steel liner, but for most woodstove inserts, the required liner can be installed inside the existing clay tiles. A properly installed new chimney liner will improve your chimney’s draft and make cleaning the system easier and less expensive.
Any new fuel burning appliances you install might require that you replace your existing chimney liner if it is not the right size or is not made of proper materials for the equipment you are installing. Even the best chimney liners are subject to deterioration over the years due to corrosive combustion products and weather. Your chimney professional will let you know if your existing liner has developed leaks due to corrosion or wear that make it necessary for you to install a new chimney liner.