Understanding the Anatomy of a Masonry Chimney This diagram provides a clear and educational breakdown of a traditional masonry chimney, revealing how each component works together to safely manage fire, smoke, and heat inside a building. While a chimney may appear simple from the outside, its internal structure is carefully engineered to ensure efficiency, durability, and safety. The Upper Components: Protection and Ventilation At the very top sits the chimney cap, which serves as the first lin