The areas where flashings are required are typically very vulnerable to water penetration. There is a high risk of water leakage and wood decay from a damaged, loose or poorly constructed flashing. For all of the above reasons, regualr monitoring and routine maintenance of the flashing areas is issential to preventing leaks. The most common materials used in chimney construction are masonry and steel. Masonry chimneys can be brick, block or stone and are sometimes stuccoed or parged.
Chimneys often have more than one flue.
A flue is a separate and distinct channel for the smoke on the inside of the chimney. In most cases, each appliance within the house must have a separate flue. In certain cases, two gas furnaces on the same floor within a house can share a common flue, as can a gas furnace and a gas hot water heater on the same level. Some wood furnaces are designed to share a flue with an oil furnace, if at the same floor level. Some flues are unlined in that there is masonry exposed on the inside of the flue.