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Lords Chimney - Chimney Sweep and Fireplace Vent Service
Lords Chimney - Chimney Sweep and Fireplace Vent Service

When it comes to chimney maintenance, most homeowners remember to clean out their fireboxes and know they need to have their chimneys swept. However, many may forget that some of the most important parts of the chimney cannot be seen from street level. One of these chimney parts that is often ignored is the chimney crown.

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What is the chimney crown?

Chimney crowns are the slightly-angled slabs that surround and protect the top of the flue. Sometimes referred to as a chimney wash, the chimney crown acts as the base for the chimney cap; chimney crowns are designed to help moisture from ice, rain, or snow to flow away from the chimney structure and safely onto the roof.

What causes chimney crown damage?

There are a number of factors that can cause chimney crown damage. One of the primary causes of chimney crown damage is improper construction. Oftentimes, inexperienced contractors build the chimney crown using mortar instead of cement. Mortar, however, deteriorates much faster than concrete, especially when constantly exposed to the elements. The can cause the chimney crown to crack and spall, allowing moisture into the chimney structure.

Another major cause of chimney crown damage is long-term exposure to the elements without upkeep. Because of their location, chimney crowns take the brunt of Mother Nature’s forces; they are constantly exposed to varying temperatures as well as large amounts of moisture. These conditions can take a toll on chimney crowns, especially if it is not correctly angled. If left too flat, water and moisture can accumulate on the chimney crown and cause further damage.

Chimney crowns may also lose their watertight seal around the flue. This happens due to long term extreme temperature variations caused by fireplace use. The hot air and gas from a fire as it travels up the flue along with the cold outside air temperatures can cause the chimney crown to expand and contract, breaking the seal. This can let water into the chimney, causing even faster deterioration.

Chimney crown repairs

If your chimney is leaking, your chimney crown may be to blame. In these cases, we often recommended either repairing or rebuilding the chimney crown. The amount of repair needed will depend on the amount of damage the chimney crown has suffered.

When building or repairing a chimney crown, one of the keys is to make sure the edges extend over the sides of the chimney structure. This lip is known as a kerf and should extend at least 2-2.5 inches beyond the sides of the chimney. This acts as a rain gutter that helps water flow away from the chimney and onto the roof.

If your chimney crown only needs minor repairs, we often recommend CrownCoat, a professional waterproofing sealant that can help protect and extend the life of your chimney crown. When applied professionally, CrownCoat comes with a 15 year warranty, giving you peace of mind that this eco-friendly product will last.

Whether your chimney crown has minor damage or needs to be complete rebuilt, trust the experts at Lords Chimney to repair your chimney crown.