September 26, 2023

If you have a fireplace in your home, it’s important to keep an eye out for damage and signs that your chimney is in need of chimney repair. A faulty chimney can lead to carbon monoxide poisoning and other serious hazards.

One common problem is damaged mortar joints. Over time, repeated exposure to wet and wintry weather can cause them to deteriorate and crack, which is dangerous for your home.

Cracked Bricks and Mortar

Brick is one of the most prized home exteriors, but it’s vulnerable to moisture. Water, ice and seasonal expansion and contraction attack it in the most elastic spot–the mortar joints. If left unattended, this damage can deteriorate masonry walls, especially the chimney stack. This deterioration can cause a chimney to lean, which may be a fire hazard.

Cracked brick and mortar can be repaired if the damage is caught early. I usually use a pre-mixed concrete patch and mortar mix to fill these cracks. The material comes in a tube and requires no water to mix it; simply apply with the corner of a putty knife.

Large cracks in the chimney crown (the sloping top of the chimney) can allow water to enter the chimney and corrode masonry. These cracks can also create a path for debris into the flue. I clean the cracks with a wire brush and then use a caulk gun to apply a complete bead of high-heat mortar to the gap.

Leaning Chimney

A leaning chimney usually points to issues with the foundation of your home. The area beneath a chimney is separate from the rest of the house’s foundation and can become weaker over time. The footing that supports the chimney can also deteriorate with water leaks, ground movement, and poor construction materials.

This can cause the chimney to sink into the soil and tilt away from your home. You can often tell if this is happening by looking at the gap that has formed between your house siding and the exterior chimney. Previous homeowners may have filled this gap with caulk, foam insulation, or mortar. However, these are only temporary fixes.

The most effective repair method today for a leaning chimney is helical piers. These are driven deep into the ground under a leaning chimney and attached to brackets that are mounted on the footing of the chimney foundation. A hydraulic jack then lifts the chimney back to its original position.

White Stains

When homeowners see white stains on their chimneys, they usually assume that the staining is caused by soot or creosote build-up. While this is sometimes the case, these stains are actually a sign of moisture and should be dealt with immediately.

Water can damage bricks and mortar structures by causing them to erode and crumble. Bricks have the ability to absorb water from rain, snow, sprinklers and even the earth through cracks that can develop for a variety of reasons and often go unnoticed until structural damage is severe. As the water moves through masonry, it dissolves the salt particles that are naturally present and leaves behind white deposits of the residue known as efflorescence.

If your chimney has white stains, it’s important to have it inspected by a professional chimney sweep as soon as possible. Our technicians can discover how the water is getting into masonry and recommend chimney repair to address the problem before it gets out of control.

Leaky Chimney

A leaky chimney is a serious problem. Even a small leak can cause serious water damage in your home and must be fixed immediately. Leaks can occur from poor flashing, a deteriorating chase top or crown, or damaged bricks.

Flashing is a curved metal sheet installed at the roofline that helps divert rainwater from the chimney and your house. This metal sheet is made to fit over the shingles and is secured with cement. Chimneys that leak during heavy rains have a flashing problem.

To test for a flashing leak, station one person in the attic or somewhere above the chimney and a second person on the ground below the roof. Have the person below the roof start to pour water on the low side of the chimney at the front, concentrating for two minutes on this spot, and note the spot on the ceiling where the first drop of water appears. Continue this process on the other lower sides of the chimney.

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