A chimney is not simply one solid piece of masonry. Instead, it is a complex structure with a number of important components that work together to help the fireplace burn safely and efficiently.
What is a chimney crown?
The chimney crown is a slab of stone or masonry that sits on the top of the chimney, covering the top of the chimney and sealing the space around the flue. This helps protect against water entry while also protecting the masonry of the chimney structure.
Chimney crowns often suffer the worst exposure to the elements out of any chimney component. Because of this, it is important that the crown is built using quality materials and good building practices. Doing this will help extend the life of the chimney crown and protect the fireplace system.
While they may look flat from the street, chimney crowns are actually built with a slight slope. This prevents water from pooling on top of the chimney crown and encourages correct drainage. Likewise, chimney crowns also have an overhang known as a kerf. Extending several inches over the edge of the chimney, the kerf directs water onto the roof instead of directly onto the masonry of the chimney.
Chimney crown damage and repair.
Damage to the chimney crown can be difficult to immediately recognize, especially if you do not regularly climb onto the roof. Because of this, chimney crown damage is typically discovered during chimney sweepings or inspections rather than because of performance problems.
Chimney crown damage typically occurs due to a combination of overexposure to the elements and poor construction. Their location and purpose mean the chimney crown is exposed to more water than most other chimney elements; this makes it more prone to leaks and cracking. Likewise, poor construction or using improper building materials can also cause the chimney crown to prematurely deteriorate.
If damage to the chimney crown is discovered, it is important to have it repaired as soon as possible. The type of repairs needed while depend on the cause and severity of the damage; small, hairline cracks may be simple masonry repairs, whereas extensive damage could require a full chimney crown rebuild.
In addition to chimney crown repairs, a waterproof sealant may be recommended. Applying CrownCoat, flexible waterproof sealant, can protect your chimney crown against further water entry or water damage.
The chimney crown plays an important role in protecting your chimney system. Because of this, it is important to have it inspected regularly for signs of damage or deterioration. To schedule your next chimney inspection or for more information about protecting your chimney crown with CrownCoat, contact Jack Pixley Sweeps today!