The chimney liner inside your flue is one of the most critical parts of your chimney system, so it is important to keep it maintained properly. The chimney liner seals the flue walls so that smoke and other combustion products cannot leak into the external chimney structure or attached building before they are exhausted out the top of the chimney. If your chimney liner leaks, it can cause problems ranging from damage to the chimney masonry structure to carbon monoxide buildup inside your house. The clay tile liners that were commonly installed in brick chimneys after the 1940′s will last for several decades unless they are damaged by external water infiltration or structural shifting. Metal liners will usually last a very long time without failing, unless they are made of an alloy that is unsuitable for the application they are installed for.

Combustion products from burning fuels contain carbon dioxide and water, plus other impurities that can condense into highly corrosive compounds under the right temperature conditions. This corrosive condensation adheres to the walls of the flue and eventually damages mortar between tile or bricks, and can eat holes in metal liners if they are not made of the right alloys. Creosote is one of the most common combustion products from burning wood. Creosote condenses inside the flue, especially near the top where the chimney is coldest, to form thick black gooey or crystalline masses that impede air flow up the chimney and represent a serious fire hazard.

In order to maintain your chimney liner properly, you should have it cleaned and inspected at least once a year by a chimney professional. If the inspection reveals damage to the walls of your chimney liner, you will need to have appropriate repairs done to keep your flue operating safely. If a clay liner has tiles broken or missing, or cracks in the parging between tiles, you may need to have the liner replaced, or have a flexible metal liner inserted inside it. If your metal liner develops leaks, it will probably have to be replaced.

There are some things you can do to maintain your chimney system to avoid future large repair costs. Install a chimney cap on top of your flu to keep rain, snow and animals out of your flue. Apply Crown Seal to the masonry crown on top of your chimney and use Crack Magic Crack Sealant to repair any external damage to bricks or mortar on your chimney. These will prevent infiltration of water from outside your chimney, minimizing freeze/thaw damage and other problems caused by moisture. Use dry wood to burn clean, hot fires to avoid creosote buildup. A carefully maintained chimney and chimney liner will give you many years of safe, enjoyable use.