Clay flue lining must extend above the enclosing walls by how many inches at a minimum?

Clay flue lining must extend a minimum of 8 inches above the enclosing walls to ensure proper venting and performance of the chimney. This requirement is crucial because the extension helps protect the flue from rain and snow, which can cause moisture-related damage. Moreover, it ensures that the flue adequately draws heat and combustion gases away from the structure, preventing backdraft and other issues associated with improper venting. An appropriate height reduction could lead to decreased chimney efficiency and increased risk of chimney-related hazards. Thus, adhering to the 8-inch minimum extension is a fundamental aspect of maintaining both safety and functionality in chimney design.