What is a chimney crown?

A chimney crown is a flat, usually concrete or metal, surface that sits at the top of a masonry chimney. It covers the top opening of the chimney and is designed to prevent water, debris, and animals from entering the chimney flue. The crown typically has a slightly sloped surface that helps direct water away from the chimney and off the roof.

The chimney crown is an important part of the chimney system, as it helps protect the chimney from water damage, which can cause expensive and potentially dangerous problems over time. A damaged or improperly installed crown can allow water to seep into the chimney structure, leading to problems such as deteriorated masonry, rusted metal components, and weakened structural supports. Therefore, it is important to have the crown inspected regularly and repaired or replaced if necessary.

A chimney crown should have an overhang and a drip edge to provide adequate protection for the chimney. The overhang refers to the horizontal extension of the crown beyond the edge of the chimney structure. The purpose of the overhang is to help prevent water from running down the sides of the chimney and instead directs it away from the chimney.

The drip edge is a small lip or groove on the underside of the overhang that helps to direct water away from the chimney and off the roof. The drip edge helps to prevent water from seeping under the edge of the crown, which can cause damage to the chimney and the surrounding roof.

Together, the overhang and drip edge work to protect the chimney from water damage, which can cause costly repairs and potentially compromise the safety of the chimney. Therefore, it is important to ensure that the chimney crown is installed properly with a sufficient overhang and drip edge.

A proper chimney crown should be constructed of durable, weather-resistant materials that can withstand exposure to the elements. The most common materials used for chimney crowns are concrete, metal, and stone.

Here are some important characteristics of a properly constructed chimney crown:

  1. Sloped surface: The surface of the crown should be sloped away from the center of the chimney to direct water away from the chimney structure.

  2. Overhang and drip edge: As mentioned earlier, the crown should have an overhang and drip edge to help protect the chimney from water damage.

  3. Thickness: The crown should be at least 2 inches thick to provide adequate strength and durability.

  4. Reinforcement: The crown should be reinforced with steel mesh or rebar to provide additional strength and prevent cracking.

  5. Expansion joints: Expansion joints should be installed in the crown to allow for natural expansion and contraction that can occur due to temperature changes.

  6. Proper sealing: The crown should be properly sealed to prevent water from seeping into cracks and causing damage to the chimney structure.

A properly constructed chimney crown is an important part of maintaining a safe and functional chimney system. It helps protect the chimney from water damage and extends the life of the chimney. Regular inspections and maintenance can help ensure that the crown is in good condition and functioning properly.