The chimney crown protects the chimney brick from being exposed to moisture from weather can, over time, deteriorate. When this happens, there is no shield above the bricks. They, in turn, become weathered and your chimney begins to deteriorate. To prevent this deterioration of your chimney, you will need to replace a leaking crown.
Evidence of a Damaged Chimney Crown
Chimney crowns must be replaced when they first fail to shield the chimney from weathering. In examining your chimney's crown, if you notice cracks or crumbling and if you begin to see the brick beneath the crown, it is time to replace the crown.