The cement or stone crown at the top of your chimney plays a crucial role in preserving the health of your fireplace’s ventilation system. Bricks and mortar tend to act like a sponge, naturally absorbing moisture. Unlike a sponge, when the moisture in masonry freezes and thaws, it breaks down. This freeze-and-thaw cycle can weaken the structural integrity of your chimney and cause thousands of dollars in damage. Protecting the health of your chimney crown can extend the life of your chimney and prevent the need for expensive repairs.
A chimney crown is a cap at the top of your chimney that covers the bricks and mortar or stones that make up the structure of the chimney. Its purpose is to prevent moisture from seeping into the chimney’s masonry where it is most exposed to the elements: at the top. It also extends over the edge of the chimney by a few inches so that rain and snow will run off onto the roof or the ground instead of falling straight down to the base of the chimney which would cause extra wear and tear to the flashing.
Chimney crowns are usually made of concrete that has been covered by a waterproofing sealant. Though they can also be made of metal or stone. A properly designed chimney crown will have a minimum slope of 3 inches per foot of run and will extend over the side of the chimney by a minimum of 2 ½ inches.
There are 4 main reasons why a chimney crown can become cracked or broken:
Overtime, the waterproofing sealant on the chimney cap will become less effective. If the crown is not retreated with sealant, water can seep into the concrete. When it freezes and thaws inside the concrete, it can begin to crack creating pathways for moisture to seep into the masonry.
If the chimney crown doesn’t have a steep enough slope or isn’t made of the correct materials, it is more likely to crack or break.
Homes shift and settle as the foundation sets and ground shifts. The chimney crown can become cracked during this process.
As the moisture content in concrete evaporates, as it dries and ages, it can cause concrete shrinkage. Sever concrete shrinkage can cause the crown to crack.
Cracks and damage to your chimney crown are hard to see from the ground. The best way to ensure your chimney crown is in good condition is to schedule an annual chimney cleaning and inspection. An annual chimney inspection and cleaning isn’t only important to check the health of your chimney crown. It is recommended by the Chimney Safety Institute of America (CSIA) and National Fire Protection Association because it is essential for preventing fires and carbon monoxide poisoning as well as expensive repairs.
Chimney Solutions specializes in chimney cleanings and chimney inspections. We are trusted by residents throughout the Atlanta area because of our knowledgeable team of chimney sweeps and commitment to excellent customer service. Give us a call to setup an appointment for an inspection to make sure your chimney won’t be damaged by this year’s spring showers!