The advent of high efficiency furnaces has helped conserve earth’s natural resources, and has also meant lower heating bills for homeowners. At the same time, high efficiency furnaces, as their name indicates, extract more heat from a given amount of fuel than conventional furnaces. Combustion is more complete and less heat is lost up the chimney. In turn, the flue seldom has a chance to “dry out” as older furnaces have allowed. Once flue gases drop to 120 F, unwanted condensation begins. Herein lies one side effect of high efficiency furnaces – excessive moisture in the flue. The combustion process itself, too, leads to condensation in the chimney. Water vapor is a by-product of burning fuel. When 1 cubic foot of gas is burned, 2 cubic feet of water vapor is created. Traditionally built chimneys with clay liners will not last under this moisture assault. Stainless steel relining is the best solution for moisture attack.

Chimney fires occur when deposits of carbon and dust accumulate in a chimney and are set alight by sparks or flames from an open fire. When wood burns slowly and produces smoke, the smoke condenses on the cool inner surface of the chimney and produces creosote deposits. Creosote is a highly flammable material. If it ignites at the base of the chimney, it can produce a raging fire that travels up the chimney at extremely high temperatures. Most solid fuels create some kind of soot which without regular cleaning of chimneys builds up in the flue and eventually catches fire.

In order for the fire to burn properly, the chimney must pull combustion air through the fireplace or stove. At times, however, there is a negative pressure in the chimney causing chimney draft. There are several causes of chimney draft such as improper flue sizing, flue blockage, resistance from below, insufficient chimney height, and so on. Relining a chimney often has a positive effect on chimney draft.

Alliance Chimney uses a video inspection system to systematically inspect your chimney. Such an inspection will be able to show any cracks in the tiles, even small ones, or any damage to the mortar between the clay chimney tiles. From this inspection we can make assessments and recommendations to the homeowner on how to proceed in alleviating all problems.

It happens thousands of times each year; damaged chimneys resulting in disaster. Poisonous carbon monoxide gas leaks through cracks in the flue lining and into the home. Even small amounts can make you and your family sick. There is also the risk of a chimney fire turning into a house fire. Highly combustible creosote can leak through even small cracks in clay linings. Once ignited, a creosote fire can find its way through the cracks, and dangerously increase chimney heat. Or the flames can simply penetrate cracks in the mortar and ignite a home. Having a few cracked flues is serious business.