Winter Weather Can Cause Damage to a Leaky Chimney
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How to Address Your Leaky Chimney This Winter Season

With an average of 5.7 inches of precipitation and freezing conditions expected along the Atlantic Corridor, winter is a rough time of year for masonry chimneys. Winter precipitation is especially troublesome for chimneys. The constant freezing and thawing throughout the winter season can cause masonry cracks that allow moisture to leak inside the flue. It can result in significant damage and weaken its structural integrity. While there is never a good time for a leaky chimney, it can certainly put a damper on enjoying a warm and cozy fireplace fire. Here’s how to address your leaky chimney this winter season so you don’t get left in the cold.

damper, annapolis mdLeaky Damper

The damper is a common source for chimney leaks. Although the damper needs to be fully open when burning wood in the fireplace to vent smoke and fumes, it is easy to forget to close it after the fire burns out. Closing the damper will help prevent heat loss and keep the firebox dry when it rains or snows outside. However, corrosion, rust, and warping could prevent the damper from shutting completely, allowing water to drip into the fireplace.

Install a Top Sealing Damper

Consider installing a top-sealing damper for maximum moisture protection. Unlike a standard throat damper located in the flue just above the firebox, a top-sealing damper is mounted at the top of the chimney. It keeps water out of the flue entirely when closed, providing maximum protection against water damage.

Missing Chimney Cap

When you have a leaky chimney, the chimney cap is another common entry point. The chimney cap is like a rain hat for the flue. It keeps rainwater and snow out of the open flue pipe while allowing fireplace exhaust to vent outside. Heavy winds and intense storms can damage the chimney cap or even blow it off entirely, exposing the flue to external elements.  If the chimney cap is missing or damaged, it should be immediately replaced with one that contains a mesh screen and spark-arrestor. The mesh screen prevents small animals, pests, and debris from obstructing the flue vent. The spark arrestor keeps hot embers flying around the flue from landing on the roof or nearby brush and sparking a fire.

flashing repair, severna park, mdWarped Chimney Flashing

The chimney flashing is a strip of sheet metal that seals the seam where the chimney meets the roof. Normal wear and tear, along with the compounding effect of winter weather for several seasons, can eventually weaken and damage the flashing due to corrosion, rusting, or warping. When the flashing is damaged, water will seep inside the chimney. You may notice water stains appearing on the ceiling and walls around the fireplace or heating stove. It’s vital to repair or replace the damaged flashing as quickly as possible to prevent water damage to the roof, attic, and ceiling.

Masonry Damage

Although masonry chimneys are incredibly durable, years of exposure to various temperature changes from hot, humid summers to freezing winter conditions can cause tiny cracks in the bricks. The porous material absorbs the moisture causing cracks to continue widening in freezing and thawing conditions. Eventually, bricks begin to flake, chip and crack. Winter weather also erodes the mortar leaving gaps in the joints. You may notice chunks or entire pieces of brick on the ground near the chimney. Chimney masons use tuckpointing to restore the chimney when masonry damage is minor. More extensive damage may require a partial or complete chimney rebuild.

Chimney Inspection

An annual chimney inspection can help homeowners prevent a leaky chimney. When chimney damage is caught early, your chimney professional will make the necessary repairs before more extensive damage results in a chimney leak.


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