Common Causes of Chimney Moisture Damage

Unexpected home repairs can put a damper on the holidays! Downpours of sleet and snow at this time of year can be tough on your chimney and expose a leak. Damage caused by a leaky chimney can cost you thousands of dollars. However, catching a problem early can dramatically reduce the spread of water damage. So be on the lookout for these common causes of chimney-related moisture damage.

What causes chimney leaks?

There are four common causes of chimney-related moisture damage: untreated masonry, damaged flashing, chimney cap trouble, cracked chimney crown/chase cover, and deteriorated masonry. Often, these problems go unnoticed until you have a professional chimney inspection. However, if you make a habit of looking over your chimney whenever you are outside, especially after a storm, you are more likely to notice if one of these problems arises.

Damaged Flashing

The material around the base of the chimney that connects it to the roof is flashing. Your chimney’s flashing might be made of sheet metal like copper, aluminum, or stainless steel, plastic, or composite materials. It plays a critical role in keeping water out of your home. Chimney flashing is a waterproof barrier that prevents precipitation from falling down the space between the chimney and roof. Chimney leaks are often caused by flashing that’s been warped or torn away by a storm.

Chimney Cap Trouble

Similar to chimney flashing, the role of a chimney cap is to keep rain, sleet, and snow from getting into your home. It sits over the top of the chimney, like an umbrella, preventing water from falling down the chimney. If your home’s chimney cap is missing or damaged, it should be replaced quickly to protect the chimney flue liner, damper, and firebox from water damage.

Cracked Crown or Chase Cover

A chimney crown or chase cover sits underneath the chimney cap. A traditional chimney crown is a concrete slab with a beveled edge that sits on top of the masonry. It prevents water from seeping directly into bricks and mortar at the top of the chimney. However, even small cracks in the crown can allow harmful amounts of moisture to seep down into the masonry. This is why even hairline cracks should be filled in to prevent moisture.

Untreated Masonry

Untreated bricks and mortar are porous. As a result, water can easily seep into the masonry. In the winter, this can lead to a destructive cycle of expanding and contracting as the water freezes and thaws. If you notice broken pieces of brick or mortar around your chimney, it may be a sign that the masonry should be treated with a waterproofing sealant. Masonry that’s been professionally treated by a waterproofing sealant will stop moisture from deteriorating the masonry.

If you spot signs of any one of these chimney problems, call on a trusted chimney service to schedule a chimney inspection. An inspection is the first step to determine the extent of the damage and determine an effective, affordable solution.

For more than 60 years, Felgemacher Masonry & Chimney has been inspecting and repairing chimneys in the Buffalo and Rochester regions of New York. Our chimney technicians are certified by the Chimney Safety Institute of America (CSIA). If you need a local chimney service, we would love to work with you! You can count on our chimney technicians to explain any chimney issues we find, recommend the best solution, and expertly repair your chimney.