A flue lining in a masonry chimney is defined as "a clay, ceramic, or metal conduit installed inside of a chimney, intended to contain the combustion products, direct them to the outside atmosphere, and protect the chimney walls from heat and corrosion". The NFPA 211 regulates that chimneys require a liner.
Liners in Chimneys Serve Three Main Functions:
1) The liner protects the house from heat transfer to combustibles. In the NBS tests, unlined chimneys allowed heat to move through the chimney so rapidly that the adjacent woodwork caught fire in only 3 1/2 hours.
2) Liners protect the masonry from the corrosive byproducts of combustion. In the tests it was determined that if the flue gases were allowed to penetrate to the brick and mortar, the result would be a reduction in the usable life of the chimney. The flue gases are acidic in nature and literally eat away at the mortar joints from inside the chimney. As the mortar joints erode, heat transfers more rapidly to the nearby combustibles and dangerous gases such as carbon monoxide can leak into the living areas of the home.
3) Liners provide a correctly sized flue for optimum efficiency of appliances. Modern wood stoves and gas or oil furnaces require a correctly sized flue to perform properly. The chimney is responsible for not only allowing the products of combustion a passage out of the house, but the draft generated by the chimney also supplies the combustion air to the appliance. An incorrectly sized liner can lead to excessive creosote buildup in wood burning stoves, and the production of carbon monoxide with conventional fuels.
Common Types of Liners
The most common types of masonry chimney liners are clay tiles. Over time, these tiles break down causing cracks and the masonry is no longer protected from byproducts of combustion. Aluminum chimney liners are used to upgrade and repair existing chimneys, but cannot withstand the corrosive natures of combustibles as wellas stainless steel liners can.
What We Use
We use a premium chimney lining system that is 316Ti and all components involved in venting the gas are made out of matched metal. The liners have had full UL testing and listing to the UL 1777standard by Underwriters Laboratories. There is also a manufacturers lifetime warranty.
Your chimney has a big responsibility. It carries toxic gas out of your home, and while doing its job, it must withstand constant attack by acid, creosote and extreme temperatures for months on end. These conditions cause chimney damage and deterioration, and when that happens, your family’s safety is in question. The risks of carbon monoxide poisoning and house ﬁres become very real.
Outside vs Inside
Look at the picture on the left. Most people would not see anything wrong with this chimney. But there is more to the story. On the inside, the chimney could be seriously damaged and not up to safety regulations.
Old vs New
Old-fashioned chimneys were not designed to vent modern heating appliances. Besides, no chimney lasts forever. Because of the hostile environment, the inside of both flue of this chimney have deteriorated. Notice the cracked flue tiles (left) and the deteriorated joints and/or misaligned flues (right). According to code, both flues should be relined.
Because of the hostile environment, the inside of both flues of this chimney have deteriorated. Notice the cracked flue tiles (left) and the deteriorated joints and/or misaligned flues (right). According to code, both flues should be relined.