Chimney cracks are a big deal for homeowners as they can compromise the structure and safety of the chimney. Understanding the causes and types of cracks is key to addressing the issue quickly and correctly. Cracks in your masonry chimney affect its appearance and can lead to bigger problems if left untreated. By knowing the root causes and types of cracks, you can take the necessary steps to keep your chimney safe and working. At GMT Home Services, we can identify and repair all types of chimney cracks, from minor to major structural issues. Don’t let a small crack turn into a bigger problem—act now to protect your home and your family.
Cracks in your masonry chimney are the first sign that it’s time to schedule a pro to inspect and repair it. Ignoring these issues can lead to more cracking, water damage, and a chimney that’s not safe to use.
Chimney cracks can be caused by:
Settlement and movement of the foundation: As your home settles over time, the foundation can shift, causing stress on the chimney and cracking.
Weathering and erosion of the masonry: Exposure to the elements (rain, snow, wind) can erode the masonry, weaken the chimney and cause cracking.
Poor-quality materials used in construction: Subpar materials used during construction can result in a less durable chimney that’s more prone to cracking.
Violent hail storms or extreme weather: Severe weather events (hail storms, extreme temperature fluctuations) can cause significant damage to the chimney and cracking.
Interior masonry damage from chimney fires and/or acidic decay from creosote and combustion gases: Chimney fires and creosote and acidic combustion gases can deteriorate the interior masonry and cause cracking.
Seasonal temperature fluctuations: The expansion and contraction of the chimney materials due to temperature changes can cause stress and cracking.
Gale force winds: Strong winds can apply pressure to the chimney and cause it to crack or lean.
Now that you know what causes chimney cracks, you can take steps to prevent further damage.
Masonry chimneys crack because of the natural settling and movement of the structure over time. As the chimney settles, the masonry shifts, and cracks form. The repeated heating and cooling of the chimney causes the masonry to expand and contract and crack. Poor-quality materials, bad construction, and harsh weather can also cause cracks in masonry chimneys.
All these factors can create stress points in the chimney and cause various types of cracks: vertical, horizontal and stair-step. Regular inspections and maintenance can catch these issues before they get worse.
The first step to fixing masonry cracks is a professional chimney inspection. At GMT Home Services, our chimney experts will inspect the damage, identify the source and recommend the best solution. Repairs may include:
Chimney waterproofing: A waterproof sealant will protect minor cracks from getting worse.
Brick replacement: Damaged or loose bricks can be replaced to restore the structure.
Tuckpointing: Replacing crumbling mortar will extend the life of your chimney.
Partial chimney rebuilding: Severe damage will require rebuilding the chimney stack.
Full chimney rebuild: In cases of extreme neglect and structural damage, a full rebuild may be required.
Vertical cracks in your chimney are not just cosmetic; they can be a sign of a deeper structural issue. These cracks are usually caused by vertical movement in the chimney due to foundation issues or the home settling.
Fix Vertical Cracks: Use a flexible masonry sealant to allow for future movement without compromising the repair. Clean and prep the area before applying the sealant for proper adhesion. If the cracks are due to foundation issues, call in the professionals to stabilize the structure.
Horizontal cracks are usually caused by thermal expansion and moisture penetration from freeze-thaw cycles. Left unattended, they can weaken the chimney’s structure.
How to Fix Horizontal Cracks: Proper expansion joints allow for masonry movement and relieve stress on the structure. Caulk or mortar repair products can work for minor cracks. For severe cracks, call in the professionals to install reinforcements.
Stair-step cracks appear in a zig-zag pattern, usually due to uneven settling or foundation movement. If ignored, they can cause further chimney damage.
How to Fix Stair-Step Cracks: Stabilize the foundation, replace cracked bricks and reinforce the masonry with steel lintels or rebar. Sealants should be applied to prevent moisture from making the problem worse. If foundation issues persist, call a structural engineer.
Due to weather exposure, crown cracks appear on the very top of the chimney, on the chimney crown. If left unattended, they can cause serious damage.
Fix It Now: Use waterproof sealants specifically designed for chimney crowns. Monitor the cracks and apply a water-repellent coating to the chimney’s surface to prevent further damage.
Spalling is when moisture causes the outer layers of brick or stone to flake off and deteriorate.
How to Fix Spalling: First, remove loose or damaged bricks and replace them with matching materials. Then, apply masonry sealants to protect the surface from further moisture damage.
Efflorescence appears as white stains caused by salt deposits left behind when moisture evaporates from the chimney. Although mostly cosmetic, efflorescence is a sign of excess moisture that can cause bigger problems.
How to Fix Efflorescence: First, eliminate the moisture source. Then, use gentle cleaning methods like dry brushing or a mild detergent solution. Fix leaks or apply water-resistant coatings to prevent further moisture.
A leaning chimney is a serious problem. Usually caused by foundation issues or poor construction, this needs to be addressed immediately to prevent collapse.
How to Fix a Leaning Chimney: Have the foundation inspected, install structural supports and make sure the soil around your home is stable to prevent further movement. Chimney braces can also stabilize the structure.
Chimney caps protect against water, pests, and debris, but they can rust or become damaged over time.
Fix a Damaged Chimney Cap: Replace it with a high-quality, rust-resistant cap that offers waterproofing and pest prevention.
Cracked flue tiles expose the chimney to high temperatures and corrosive byproducts, which can cause leaks, including carbon monoxide.
How to Fix Damaged Flue Tiles: Replace damaged tiles. This involves removing old tiles and installing new ones securely to restore the chimney’s function.
Mortar deterioration, caused by weathering and moisture, weakens the chimney’s structure and compromises safety, especially the mortar joints.
How to Fix Mortar Joint Damage: Lime-based mortar is flexible and durable, making it perfect for repairing mortar joints. It accommodates minor structural shifts and extends the life of your chimney.
Spotting damage early will save you from costly repairs. Look for these warning signs:
Water in the firebox
Damp patches on ceilings or walls near the chimney
White stains (efflorescence) on the exterior masonry
Crumbling mortar on the roof or around the fireplace
Rusty or squeaky fireplace damper
Musty odours from the fireplace
If you see any of these, call GMT Home Services for a professional inspection and repair to keep your home safe and your chimney in shape.
Our industry-leading cleaning and repair company operating in Connecticut, Massachusetts, and Rhode Island. With a proven 12-year track record, we’ve successfully completed over 2,781 projects in the area. With years of professional experience and a strong commitment to customer satisfaction, we consistently uphold our legacy of excellence in every job we complete.
Several factors affect the cost of chimney repair, with the type of repair being the most important. Minor cracks are relatively affordable to fix, but larger structural issues like straightening a leaning chimney can cost thousands.
Here are some common factors that affect chimney repair costs:
Chimney Type: The material and design of the chimney (masonry, metal or prefabricated) affects the repair cost.
Repair Type: Minor cracks, repointing or water damage repairs are less expensive than extensive repairs like chimney rebuilding.
Emergency vs Standard Repairs: Emergency repairs come with a premium charge compared to standard scheduled services.
Chimney Height and Accessibility: Taller chimneys or those in hard-to-reach areas may require special equipment or scaffolding, which will increase the cost.
Chimney Condition: The more severe the damage, the more expensive the repairs will be.
Chimney Location: Local labour rates and permit requirements can affect the cost based on location.
Extent of Damage: More damage, especially involving multiple structural components, will increase the repair cost.
Chimney problems should be addressed as soon as you see them to avoid more serious and costly issues. Here are some signs your chimney needs repair:
Visible cracks or gaps in the structure
Deteriorating bricks or mortar
Water damage or leaks around the chimney
Unpleasant odors or fumes in your home
Repointing involves replacing deteriorated mortar joints between the chimney’s bricks or stones while leaving the undamaged bricks in place. It is less expensive than rebuilding and restores stability and appearance.
Rebuilding: When bricks or stones are badly damaged, cracked or spalling, rebuilding is required. This involves dismantling the existing chimney and building a new one. Rebuilding is recommended when the chimney’s structure is compromised.
Regular maintenance and inspection will prevent future cracks. Homeowners should:
Get Annual Inspections from a Certified Chimney Sweep: A professional chimney sweep can catch issues before they become major problems.
Clean the Chimney Regularly to Prevent Creosote Buildup: Regular cleaning will prevent creosote buildup, which can cause chimney fires and damage.
Check the Chimney for Damage or Wear: Look for visible cracks, damaged bricks or deteriorating mortar joints.
Address Issues Quickly to Prevent Further Damage: Fix minor issues before they become major problems.
Consider Applying a Waterproof Sealant to the Chimney to Prevent Water Infiltration: A waterproof sealant will protect the chimney from water damage and reduce the risk of cracks.
By following these steps, you will prevent future chimney cracks and keep your chimney safe and sound. Maintenance and inspections are key to keeping your chimney in top shape and avoiding costly repairs later on.
With years of professional experience and a strong commitment to customer satisfaction, we consistently uphold our legacy of excellence in every job we complete.
Ensure the safety and efficiency of your fireplace by scheduling your relative chimney service with GMT Home Services today we are committed to providing top-notch various chimney services to ensure your home is safe and your fireplace is running efficiently.
Our experienced technicians offer a comprehensive range of chimney services tailored to your specific needs. From thorough cleaning and inspections to repairs and maintenance, we’re committed to keeping your home safe and your fireplace functioning optimally.
Experience the benefits of a cleaner, healthier home by scheduling your required chimney service with us today.
For any inquiries or to book an appointment
