How to Repair Cracks in a Chimney
Chimneys are one of those parts of the home we often overlook—until something goes wrong. You light a cozy fire or fire up your furnace, and all seems well… until you notice a crack running along the side of your chimney. Whether it’s a small hairline fracture or a deep, crumbling split, chimney cracks are not something to ignore.
They may start small, but left untreated, they can lead to much bigger problems: water leaks, smoke issues, structural damage, and even fire hazards. That’s why understanding how to spot and repair chimney cracks is a must for any homeowner—especially here in Minnesota, where harsh winters only make things worse.
In this article, we’ll go over everything you need to know about chimney crack repairs, from spotting early signs of damage to understanding the real Cost Chimney Repair might involve. We’ll also share expert tips from Murphy Masonry, a trusted name in chimney repair services in Minnesota.
Why Do Chimney Cracks Happen?
Your chimney is exposed to everything the weather throws at it—rain, snow, freezing temperatures, strong winds, and intense summer heat. Over time, this constant exposure causes the materials—especially brick, mortar, and concrete—to wear down and crack.
Some of the most common causes of chimney cracking include:
Freeze-thaw cycles: Moisture enters small gaps, freezes, expands, and worsens the crack.
Shifting foundation: As your home settles, the chimney can shift or tilt.
Age and weathering: Old mortar and brick begin to break down naturally.
Poor construction: Chimneys built with low-quality materials or poor technique often don’t hold up.
Water infiltration: Once water seeps into a crack, it starts damaging the surrounding structure.
These cracks, even if they seem minor, can lead to significant issues if not addressed promptly.
Spotting the Different Types of Chimney Cracks
Not all chimney cracks are created equal. Some are mostly cosmetic, while others may indicate more serious structural concerns.
1. Hairline Mortar Cracks
Small, thin cracks between bricks. These often happen due to aging or slight settling. While they may not be dangerous right away, they allow water in and can grow quickly if ignored.
2. Crown Cracks
The crown is the concrete top of the chimney. Cracks here are very common and dangerous because they’re a direct entry point for water. Repairing or replacing a cracked crown is one of the most important fixes.
3. Brick Spalling
Spalling occurs when the face of the Brick flakes or chips away. It’s often due to moisture damage or poor-quality materials. Spalled bricks need to be removed and replaced before they compromise the structure.
4. Vertical or Horizontal Cracks
These cracks can run along the entire chimney and are often signs of movement, settling, or serious stress. This type of damage should be inspected immediately by a professional.
Can You Repair Chimney Cracks Yourself?
Some homeowners are handy and may be tempted to fix chimney cracks themselves. If the damage is very minor—such as a few hairline cracks in the mortar—you can do a small DIY patch job. However, more serious issues should be handled by a professional.
Here’s a quick look at a basic DIY repair:
What You’ll Need:
Wire brush
Mortar mix or chimney sealant
Caulking gun
Trowel
Ladder and safety gear
Steps:
Clean the area: Use the wire brush to clean loose debris from the crack.
Apply mortar or sealant: Fill small cracks with a waterproof chimney caulk or fresh mortar.
Smooth the surface: Use your trowel or a gloved finger to smooth out the repair.
Let it cure: Give it at least 24–48 hours to dry completely.
Keep in mind, this only works for surface-level cracks. If there’s crumbling brick, deep gaps, crown damage, or flue issues, it’s time to call in an expert.
Why You Should Hire a Professional in Minnesota
Minnesota’s freeze-thaw cycles are tough on chimneys. When water seeps into a crack and freezes, it expands and causes further cracking. Over time, this can cause bricks to loosen, chimneys to lean, or even collapse. That’s why it’s essential to hire experienced Chimney Repair Services In Minnesota who understand local weather conditions and construction standards.
A professional will do more than just patch a crack—they’ll:
Inspect the entire chimney for hidden damage
Identify the root cause of the cracks
Recommend long-term solutions (not just quick fixes)
Use proper materials rated for Minnesota’s climate
Ensure your chimney meets building and fire codes
One name that stands out in this field is Murphy Masonry.
Murphy Masonry: Trusted Chimney Repair Experts in Minnesota
When it comes to chimney work, Murphy Masonry is a name many Minnesota homeowners know and trust. Their team specializes in diagnosing and repairing chimney cracks, restoring damaged brickwork, and ensuring your chimney is both safe and functional.
What makes Murphy Masonry stand out:
Years of experience with Minnesota homes
Skilled masons trained in both traditional and modern repair techniques
Honest assessments and no-pressure consultations
Clean, efficient service
Long-lasting results backed by professional standards
Whether you need a simple mortar touch-up or a full chimney rebuild, Murphy Masonry has the tools, experience, and know-how to get the job done right.
The Real Cost: Chimney Repair Pricing Breakdown
Let’s talk numbers—because that’s often the first question people ask: “What’s the cost of chimney repair?”
The cost of chimney repair varies based on the type and extent of the damage.
Keep in mind, prices can vary depending on the height of your chimney, accessibility, materials used, and labor rates. To get an accurate estimate, schedule an on-site inspection with a local expert like Murphy Masonry.
Prevention Tips: Keep Cracks from Coming Back
Once your chimney is repaired, you’ll want to keep it that way. Here’s how:
Schedule regular inspections—ideally once a year, especially before winter.
Seal the crown and flashing to keep moisture out.
Install a chimney cap to block rain, snow, and debris.
Keep your gutters clean, as overflowing water can damage nearby masonry.
Repair small cracks quickly to avoid bigger repairs later.
Taking small steps now will help extend the life of your chimney—and save you from costly repairs down the line.
Final Thoughts
Chimney cracks aren’t just a cosmetic issue—they can signal deeper structural problems and create serious risks for your home. While small cracks may seem harmless at first, water, weather, and time will make them worse.
Knowing when you can DIY and when you should call a pro is key. If you’re in Minnesota and want peace of mind, it’s best to work with an expert like Contact Murphy Masonry, a leader in chimney repair services in Minnesota.
From evaluating damage to providing lasting repairs, they make sure your chimney stays solid, safe, and ready for whatever the weather brings.
