How much should masonry chimneys extend above the roof when near adjacent buildings?

Masonry chimneys should extend a minimum of 2 feet above the roof surface when they are located within a specific distance of adjacent buildings. This requirement helps to ensure that smoke and other combustion byproducts are properly vented above the roofline, reducing the risk of fire hazards and ensuring the safety of nearby structures.

When a chimney is too close to another structure, it is crucial that the height is sufficient to prevent any possible issues with smoke or gas buildup in the area, which can lead to dangerous situations such as reduced air quality or potential fire risks. The 2-foot height serves as a standard guideline set by various building codes and safety practices aimed at safeguarding both the chimney itself and neighboring properties.

In contrast, the other options either do not meet the mandated safety standards or may not provide adequate clearance for effective venting. Therefore, understanding the importance of the 2-foot extension helps ensure compliance with safety regulations and promotes best practices in chimney installation.