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There’s something truly charming about a classic masonry chimney, isn’t there? It adds character, warmth, and a cozy focal point to any home. But as beautiful as these chimneys are, they can also be a source of frustration—especially when they start leaking. If you’ve noticed water stains, crumbling bricks, or dampness around your chimney, you’re not alone. Leaky masonry chimneys are a common problem, but luckily, they’re also fixable.

In this post, we’ll dive into why masonry chimneys leak and share practical tips on how to stop the water intrusion. Whether you’re a DIY enthusiast or thinking about calling in a professional, understanding the problem is your first step to keeping your home dry and your chimney in great shape.

Why Do Masonry Chimneys Leak?

Masonry chimneys are made from bricks or stone held together with mortar, which is porous by nature. Over time, weather elements like rain, snow, and ice can wear down the mortar joints and bricks, creating tiny cracks and gaps. Water then finds its way inside, leading to leaks that can damage the chimney structure and even the interior walls of your home.

Common causes of chimney leaks include:

• Deteriorated mortar joints: Mortar can crumble and crack with age and exposure to the elements.
• Cracked or damaged bricks: Bricks can spall (chip or crack) due to freeze-thaw cycles.
• Damaged chimney cap or crown: The crown is the top cement layer that seals the chimney; cracks here allow water to seep in.
• Faulty flashing: Flashing is the metal barrier where the chimney meets the roof, and if it’s damaged or improperly installed, leaks are inevitable.

How to Fix a Leaky Masonry Chimney

Fixing a leaky chimney involves a combination of inspection, repair, and preventive maintenance. Here’s a straightforward approach:

1. Inspect the Chimney Thoroughly: Look for visible cracks in bricks and mortar, damaged flashing, and any gaps around the chimney crown or cap.
2. Repoint the Mortar Joints: Remove crumbling mortar and refill the joints with fresh mortar. This process, called repointing, restores the chimney’s waterproof barrier.
3. Replace Damaged Bricks: If bricks are severely cracked or spalled, they may need to be replaced to prevent leaks.
4. Repair or Replace the Chimney Crown: Seal any cracks in the crown with a waterproof masonry sealant or have a professional replace it if it’s beyond repair.
5. Fix the Flashing: Ensure the flashing is properly sealed and replace any damaged sections to stop water from leaking at the roofline.
6. Apply Waterproof Sealant: After repairs, apply a breathable masonry water repellent to prevent future water penetration while allowing trapped moisture to escape.

While some of these steps can be tackled as weekend projects, others—like flashing repair—are best handled by professionals to ensure a watertight seal.

Preventive Tips to Keep Your Chimney Dry

Once you’ve fixed the leaks, prevention is key. Regular maintenance can save you from costly repairs down the road. Consider these tips:

• Schedule annual chimney inspections, especially before the rainy or winter season.
• Keep the chimney cap in good condition to prevent rain and debris from entering.
• Trim nearby tree branches to reduce debris buildup and minimize moisture retention.
• Ensure proper attic ventilation to reduce condensation inside the chimney structure.

One small step like sealing your chimney can make a big difference in protecting your home from water damage.

Wrapping Up

Leaky masonry chimneys might seem daunting, but with the right knowledge and care, you can keep yours dry and sturdy for years to come. Whether you choose to do a bit of the work yourself or hire a pro, understanding the problem is half the battle won.

Next week, we’ll explore the fascinating world of chimney liners and why they’re essential for both safety and efficiency. Until then, stay dry and cozy!

When it comes to maintaining a safe, efficient, and cozy home, your chimney plays a crucial role. Whether you rely on it for warmth, ambiance, or both, having a trustworthy partner to handle all your chimney needs makes all the difference. That’s where Dietershagen.com shines. Let’s dive into why this service stands out and why it might just become your go-to for chimney care.

Reliable Expertise You Can Count On

Chimneys require specialized knowledge, and Dietershagen.com offers exactly that. With years of experience under their belt, their team understands the ins and outs of chimney inspection, cleaning, repair, and maintenance. This expertise ensures that your chimney operates safely and efficiently, minimizing risks like chimney fires or smoke damage.

Comprehensive Services for Every Chimney

Whether you own a traditional wood-burning fireplace, a gas insert, or a modern pellet stove, Dietershagen.com provides tailored services to meet your specific needs. From routine cleanings and thorough inspections to complex repairs and chimney relining, they cover it all. This kind of all-in-one service saves you the hassle of juggling multiple contractors.

Safety First, Always

One of the biggest benefits of choosing Dietershagen.com is their commitment to safety. Regular chimney maintenance is essential to prevent hazards like creosote buildup, blockages, or structural damage. Their professional team uses the latest tools and techniques to spot potential issues before they become costly problems, giving you peace of mind.

Customer-Focused Approach

At the heart of Dietershagen.com is a genuine dedication to customer satisfaction. They understand that inviting service professionals into your home requires trust. That’s why they prioritize clear communication, punctuality, and respect for your property. Plus, their friendly team is always ready to answer your questions and provide advice tailored to your chimney’s condition.

Convenience and Efficiency

Life is busy, and scheduling home maintenance can sometimes feel like a chore. Dietershagen.com makes the process seamless, with easy online booking and flexible appointment times. Their efficient service means less disruption to your day and quicker solutions to your chimney concerns.

Wrapping Up

Your chimney is more than just a part of your home’s architecture—it’s a key player in comfort and safety. Choosing Dietershagen.com means you’re partnering with experts who care deeply about their craft and your well-being. So, whether it’s time for a routine check or you need a specific repair, you can count on them to deliver quality and peace of mind.

Stay warm, stay safe, and keep an eye out for next week’s post, where we’ll explore some easy DIY fireplace maintenance tips to help you get the most out of your cozy space!

A chimney operates on a simple principle: hot air rises .By containing and venting hot smoke and gases, the chimney creates a draft that pulls fresh air into the fire, which keeps it burning efficently.

A traditional domestic fireplace chimney is made of five main parts:

• The Firebox: Opening which is built out of Fire proof brick where you place wood into to burn.

• The Throat: The opening immediately above the fire. It narrows just below the damper, a metal plate that can be closed when the fireplace is not in use to prevent heat loss.
• The Damper: Metal plate which you open and close to allow smoke to exit the chimney flue .This is not called a FLUE which so man homeowners call it from being misinformed(aka see the movie jaws and even on jepordy they called it a flue). You can never open a flue because the flue is just the passage way where all the smoke and soot exits!!!!

• The Smoke Chamber: Located above the damper, this chamber has a smoke shelf at its base. The shelf is designed to catch any downdrafts and prevent them from blowing smoke into the room. The chamber itself then narrows toward the top, acting as a reservoir for smoke to help with draft issues.

• The Flue: This is the main shaft of the chimney, which carries the smoke out of the house. Fireplace flues can be made out of clay ,metal or pumice to contain the heat and protect the chimney.

Types of Chimneys

There are two main types of fireplace chimneys used in homes today

Masonry Chimneys: These are built onsite from brick or stone and are a permanent part of the homes structure. They can be heavy and expensive but are very durable.

Prefabricated (Factory-Built) Chimneys: These are manufactured in a factory and assembled on-site. They are typically lighter and more affordable than masonry chimneys but may be less durable and harder to repair if parts are discontinued.

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Copper flashing is critical for protecting a building structure from water damage because it offers unmatched durability and longevity that often exceeds the life of the building structure itself .It’s primary importance lies in the ability to function as a permanent ,reliable barrier against moisture.

Superior Longevity and Protection

The main advantage of copper flashing is its exceptional service life, often lasting for 80 years or more. Unlike other materials ,it naturally resists corrosion from harsh conditions, including salt water in coastal environments and the chemicals found in fresh mortar. This resilience makes it a fit and forget solution, as it often does not need to be replaced when the roof is re-done, providing a lifetime of protection if done correctly!!!

Cost-Effectiveness and Sustainability

While the initial cost of copper is higher than some alternatives, it’s longevity makes it highly cost- effective i the log run. Replacing failed flashing is an expensive, and disruptive process. Copper flashing eliminates this risk, often representing a tiny fraction of a building’s total cost while protecting the entire structure.

Copper flashing needs to be installed by a qualified specialized contractor with the skills to install correctly!!!

Low draft in a heating chimney for a furnace or a boiler chimney is typically caused by one or more of the following factors:

1. Insufficient chimney height:

• Chimneys that are too short relative to the roofline or nearby trees/ buildings cannot generate enough natural draft. Stack effect increases with height.

2. Blockage or obstruction :

Creosote buildup, animal nests ,leaves, soot, or structural debris restrict airflow.

3. Negative pressure indoors:

• Exhaust fans, clothes dryers, or tight building envelopes can depressurize the house, competing with the chimney for air.

4 .Cold chimney (poor warm-up): A cold chimney column is denser and resists upward flow until warmed by combustion gases. Common with intermittent heating cycles.

5. Oversized flue :

• If the flue cross section is too large, gases cool excessively before rising, reducing draft velocity.
• 6 . Air supply starvation :
  • No dedicated makeup air for combustion leaves the appliance fighting for oxygen ,especially in sealed homes.
  • 7. Leaky flue or poor connections :
  • Cracks, gaps, or disconnected sections allow dilution air or cause pressure losses.
  • 8. Excessive horizontal runs or too many elbows:
• Increases friction and reduces effective draft pressure.
• 9. External wind effects :
• High wind near a low chimney top or improper cap can create downdraft or flow reversal.

Immediate Checks:

• Inspect for visible blockage
• Verify chimney height relative to roof peak.(typically 2 feet above highest peak of house within 10 feet.)
• Test by briefly opening a nearby window or disconnecting fans to see if draft improves.
• Measure draft with a manometer.

If low draft persists, a qualified chimney technician should evaluate for flue sizing issues or structural repairs

A chimney cap is a small but crucial component of your home’s heating system. While often over looked ,its importance spans safety, efficiency, and cost savings.

Here is a breakdown of why having a chimney cap is essential:

1.Prevents Water Damage (The #1 Reason)

Water is a chimney’s worst enemy. A cap acts lie an umbrella, keeping rain and snow out.

• Without a cap: Water seeps into bricks, and mortar. In winter, freeze-thaw cycles cause cracks and crumbling(spalling).Water also rusts, the metal damper and firebox, leading to expensive masonry and metal repairs costing thousands of dollars.
• With a cap: The chimney structure stays dry and intact.

2.Blocks Animals And Nesting Material

Your warm, dark chimney is an ideal home for squirrels, birds, racoons, and bees.

• Without a cap: Animals can fall into the firebox ,die and create a terrible odor. Their nest block the flue which forces dangerous carbon monoxide and smoke back into your home.
• With a cap: A properly screened cap keeps all critters out while allowing smoke to escape.

3. Prevents Fire Hazards(Spark Arrestor)

Many caps include a metal mesh screen.

• Without a cap : Live embers and sparks can float out of the chimney and land on your roof, dry leaves, or a neighbor’s property, potentially starting a house or wild fire.
• With a cap : The screen stops sparks while letting smoke pass, significantly reducing roof fire risk.

4. Stops Downdrafts and Improves Air Quality

Wind blowing over a flat chimney top can push smoke and dangerous gases back down into your living room.

• Without a cap : You experience a smoky fireplace, sooty smells on windy days, and potential exposure to carbon monoxide (CO), and odorless, deadly gas.
• With a cap : Many caps are designed to deflect wind, creating a vacuum effect that actually helps draw smoke up and out.

5. Reduces Creosote Buildup

Creosote is a sticky, flammable byproduct of burning wood.

• Without a cap : Leaves, t wigs, and rain mix with creosote on the chimney top, forming a hard, tar- like glaze that is extremely difficult to remove and highly flammable (leading to chimney fires.)
• With a cap: Debris is blocked, keeping the flue cleaner and reducing the need for dangerous chemical cleaning.

6.Prevents Debris Blockage

• Without a cap: Leaves, twigs, and even birds’ nests can fall into the flue, creating a physical blockage. You might not notice until smoke backs up into your house or a carbon monoxide alarm goes off.
• With a cap: The flue remains clear and open.

When You Absolutely Need One

While all chimneys benefit, a cap is critical if:

• You have a wood-burning fireplace(high heat, lots of sparks).
• You live in an area with rain, snow, or freeze-thaw cycles.
• You have trees near your house (Falling leaves and branches)
• You live in a windy location (downdrafts).
• You have animals in your neighborhood (almost everywhere).

The One Exception ( Metal Liners)

If you have a modern, high efficiency gas or pellet stove with a sealed metal chimney that has a built in rain cover and spark arrestor, you may not need a separate cap. However, most traditional masonry or prefab chimneys absolutely do

Cost vs. Consequence

• Cost of a basic standard size cap: 250-400.
• Cost of not having a cap: 1000-10,000 + for masonry repair, animal removal, water damage restoration, or even a house fire.

Bottom line: A chimney cap is one of the cheapest, most effective insurance policies you can buy for your home and family. If your chimney doesn’t have one, schedule an installation before the next rainstorm or heating season.

Deterioration of the Original Liner(The Most Common Reason)

Many older chimneys(pre-WWII) were built without a proper liner at all, just bare brick or stone .Others have clay tile liners, which have a lifespan of 50-75years.Over time, these materials fail.

Cracks & Gaps: Freeze-thaw cycles, settling foundations, and normal expansion/contraction cause bricks, mortar, and clay tiles to crack. These gaps provide a direct path for heat ,sparks, and toxic gases (like deadly Carbon Monoxide) to seep into your walls or living space.

• Spalling: Moisture gets into the masonry. When it freezes, it expands, causing the surface of the bricks or tiles to flake and crumble away. This debris (called “scaling”) can fall and clog the flue.
• Missing Mortar: The mortar joints between clay tiles can wash out over time, creating holes and catching dangerous creosote buildup.

2. Corrosion from Modern heating system

This is a huge, often overlooked problem. The exhaust from modern, efficient heating appliances (like gas furnaces and water heaters) is cooler and more acidic than hot smoke from an old coal furnace.

• Acidic Condensation: The cooler flue gases can condense inside the chimney, creating a mild solution of sulfuric and nitric acid. This acid slowly eats away at traditional masonry and clay liners, a process called “acid etching”. Over a few years, it can turn a solid clay liner into something resembling soft, crumbly shale.
• Metal Liner Corrosion: Even metal liners(aluminum or galvanized steel) can be quickly corroded by acidic condensate from gas appliances. For gas, only stainless steel is truly safe long-term.

3. Improper Flue Size for a New Appliance

When you replace an old ,inefficient appliance(like an old boiler or open fireplace) with a modern, efficient one(like a gas furnace or wood stove insert) the new appliance has a different exhaust volume and temperature.

• An oversized Flue is a Disaster: The old chimney was built, for a roaring fire. Your new efficient appliance produces much less hot gas .That gas rises too slowly through the huge, cold flue.
• This leads to:

• Poor Draft: The smoke and gases get sluggish and may spill into the room.
• Excessive Condensation: The gases cool too much before exiting, leading to the corrosive condensation mentioned above.
• Creosote Buildup: In wood-burning appliances, slow-moving gases deposit far more flammable creosote.

The solution: A new, correctly sized metal Liner (a “Flue relining”) creates a smooth, perfectly- sized passageway for your new appliance, ensuring a strong draft and safe venting.

4. Damage from a Chimney Fire

Even a small chimney fire can cause catastrophic damage that is not visible from the outside. The extreme heat (over 2000 degrees F) can :

• Crack or shatter clay tile liners.
• Explode mortar oints.
• Cause the entire masonry structure to bulge.
• Melt the solder in a metal prefab chimney.

A Level II chimney inspection with a video camera is required to see this damage, which almost always necessitates a full reline.

5. Change in Fuel Type

Switching fuels is a major event for a chimney.

• Converting from wood to gas: The wood flue is likely, oversized and may be damaged.It must be relined to handle the acidic, cool gas of the new appliance.
• Converting from gas to wood : The gas flue is likely to small, not rated for high temperatures of a wood fire, and may-be made of corroded, unsafe metal. It must be relined.

The Bottom Line :What is a Liner’s Job

Think of the chimney liner as a three-part safety system. It must:

1. Contain the Hazard: Keep the heat, sparks, smoke, and deadly CO inside the flue and outside your house
   • 2 .Protect the house : Prevent the heat from transferring through the masonry and igniting nearby wood framing (a major cause of house fires).
   • 3 . Withstand the Byproducts : Be chemically resistant to the specific type of exhaust ( acidic for gas, hot and sticky for wood).

When a liner fails at any of these jobs, relining is not an upgrade- it’s a critical safety repair.

A note on the Relining Process

Today, relining doesn’t mean rebuilding the chimney. The most common method is to pull a new, continuous metal liner down the chimney. A professional will :

1. Sweep and clean old flue
   • 2.Lower a flexible stainless steel pipe from the top.
   • 3. Connect it to your appliance at the bottom.
   • 4. Insulate the space around the new liner (when required by code).
   • 5. Cap the top with a weatherproof, animal-proof termination.

In Summary : You need to reline a chimney when the original path to the outside has become unsafe. This is due to damage from time, corrosion from modern appliances, a change in what you’re burning, or the wrong flue size. It’s a direct investment in preventing house fires and carbon monoxide posisoning.

The Core Reason: Preventing Chimney Fires

The #1 reason to clean your chimney is to remove creosote. .Creosote is a highly flammable, tar like/Black or Brown substance that condenses inside your chimney flue from the smoke of burning wood.

*How it forms: When wood burns, the smoke contains unburned gases wood particles ,water vapor, and minerals .As this hot smoke travels up the cooler chimney, it condenses, leaving creosote on the walls.

• The danger: Creosote can be a light, fluffy soot, or it can be a hard, glazed, gummy tar The glazed variety is the most dangerous. A small spark or a very hot fire can ignite this buildup.
• A Chimney Fire: When creosote catches fire, it burns at 2,000 F or more. The roaring fire inside the flue can:
• Crack the chimney liner and masonry bricks.
• Set fire to the wooden framing of your house(which is often touching the outside of the chimney.
• Explode outward ,sending burning debris onto your roof and yard.
• Signs of a chimney fire: A loud roaring or popping sound, dense smoke pouring from the top, and a “tornado ” of a flame. Many chimney fires happen slowly and go unnoticed until a later inspection reveals the damage.

3 Other Critical Reasons for Cleaning (Beyond Fire Prevention)

1.Prevents Carbon Monoxide(CO) Poisoning-“The Silent Killer”

A blocked chimney prevents toxic gases from, escaping. When you light a fire, the smoke must go up.

*The Blockage: Creosote, animal nests(birds, Squirrels ,racoons) leaves or even collapsed Masonry can block the flue

• The Result: Carbon monoxide and other poisonous gases are forced back into your home.CO is odorless, colorless, and deadly. Symptoms include headaches, dizziness, nausea, and confusion-easily mistaken for the Flu.
• Cleaning ensures a clear path for all combustion gases to exit safely.
• 2. Improves heating Efficiency(Saves you Money)
• A dirty chimney doesn’t draw properly

Poor Draft: Creosote buildup reduces the diameter of the flue, like a clogged artery. This creates poor “draft” ( the suction that pulls air into the fire and smoke up the chimney).

*The Result: Your fire burns poorly, smolders, and produces more smoke and creosote(a vicious cycle). You lose heat up the chimney and have to burn more wood to stay warm.

• A clean chimney allows for a strong, hot draft, meaning a hotter fire, Less smoke, and more heat in your home.

3. Extends The Life Of Your Chimney( Prevents the separation We Discussed)

A dirty, neglected chimney leads to physical damage.

• Acidic Creosote : Creosote is acidic. When it sits on brick and mortar, especially in damp conditions, it eats away at the material, causing it to crumble (spall).
• Freeze-Thaw Damage : Creosote often holds moisture against the flue walls. When that water freezes, it expands and cracks the masonry.
• The Result : A crumbling chimney is a weak chimney. The Foundation can settle unevenly, the masonry can crack and lean, and it will eventually separate from the house as we discussed.
• Cleaning removes the acidic, moisture-holding creosote, protecting the physical structure of the chimney.

How often should you clean your chimney

The National Fire Protection Agency(NFPA) standard says:

“Chimneys, Fireplaces, and vents shall be inspected at least once a year for soundness, freedom from deposits, and correct clearances .Cleaning shall be performed when necessary).

In plain English : Get an annual inspection, and clean as needed. The actual cleaning frequency depends on usage.

Fuel /Usage

Wood Fireplace ( Frequent use) Every one cord of wood or once a year)

Wood stove ( primary heat ) Every 1-2 months of heavy use, or at least twice a season.

Gas Fireplace Every 1-2 years ( for debris, spiders or liner damage- less creosote)

Pellet stove Every 1 ton of pellets or once a year.

Any Fireplaces used occasionally Still inspect annually- animals and moisture are year-round threats.

Signs Your Chimney Needs Cleaning Now

• Fire is hard to start and smoke spills, into room.
• A strong acrid smoky smell comes from the fireplace even when not in use
• You see black, flaky, or tar like deposits in the firebox or falling from the damper.
• A 1/8 -inch or thicker layer of creosote in the flue.
• You had a slow, smoky, or smoldering fire recently. These produce the most creosote..

Who should clean your chimney is a chimney professional don’t use chemical logs or try to do yourself.

Use Dieters Hagen Long island’s most trusted name for over 75 years. Call now for your appointment.

1.Differential Settlement (The FoundationProblem)

This is the most common cause. The chimney and the house are heavy objects with their own separate concrete footings.

The house footing: Sits on soil that is kept relatively dry by the roof’s eaves and gutters.

The Chimney Footing: Sits on soil that gets repeatedly soaked by rain running down the outside of the Chimney.

>The Result: The wet soil under the Chimney footing can compress or wash away, causing the Chimney to sink(settle) slightly. The house footing, on drier soil, doesn’t sink as much. The Chimney pulls away as it goes down.

2.Thermal Expansion and Contraction

This is a daily cycle of movement

>The Chimney(Masonry): Brick stone or concrete block is a dense slow moving material. The house and chimney are moving and flexing at a different pace. The connection between them simply fatigues and cracks.

3. Moisture and Freeze-Thaw Cycles(The Water Effect)

Water is the ultimate enemy of masonry

• >Water gets into the tiny crack between the chimney and the house.
• >The temperature drops below freezing .The water turns to ice, expanding in volume by about9 %.
• This expansion acts like a hydraulic wedge, forcing the gap just a tiny bit wider.
• >The ice melts, the gap fills with water again ,and it freezes again. Repeat this cycle enough times and the gap grows from a hairline crack to a visible separation.

4.Different Structural Stiffness(The wobble effect)

>Wood frame houses are designed to sway and flex slightly under wind loads or seismic activity.

>Masonry chimneys are incredibly, rigid and brittle. They do not bend or sway ,they prefer to crack.

>The result: When the wind blows, the flexible house moves a little, but the rigid chimney tries to stay still. The only place this conflict can resolve is at their connection point, which pulls apart.

5.Poor Original Construction

Sometimes ,it’s simply because the builder failed to properly connect the two. T he metal wall ties(strips embedded in the mortar to tie the chimney to the house frame) may have been:

>Made of uncoated steel and rusted away

>Installed incorrectly or too few in number.

>Missing entirely

Is it Dangerous?

Yes it can be. A separation of more than 1/2 to 1 inch is a serious red flag.

1. Fire Hazard: The gap allows sparks ,hot gases and extreme heat to escape the chimney and directly contact the wood framing of your house ,hidden inside the wall. This is a primary cause of house fire
2. Structural Collapse: A chimney that has separated significantly is no longer braced by the house. It can become a tall, unstable column of heavy masonry that could collapse onto the roof or, in a worst-case scenario, into the house.
3. Water Damage :The gap is a direct highway for rain, snow and pests (like squirrels and bees to enter your walls and attic.

1 Freeze -thaw cycles Primary Cause

Water seeps into tiny cracks in the bricks .When temperatures drop below freezing ,the water expands about 9%.The expansion creates, internal pressure cracking the bricks surface. Over repeated cycles chunks of the brick face break off—– this is called spalling

2. * Soft, porous brick(common in older chimney)*Over fired bricks,*Bricks not rated for exterior use.

3.Failed of missing crown.( Cement slab at top of the chimney that has a pitch to it so water doesn’t sit on top of the chimney.

4. Defective of no chimney cap.

5. Mortar joint deterioration Mortar is softer and more porous than brick by design. When mortar erodes due to age crack open up, allowing more water to reach the brick edge .Once water gets behind the brick face spalling accelerates.

6 Efflorescence& Salt attack** Efflorescence is a white powdery deposit which is a sign of soluble salts inside the brick .As water moves through ,it brings salts to the surface. When water evaporates ,salt crystals, grow inside the brick pores, exerting pressure and causing flaking.

Poor flashing. Chimney flashing should be water tight copper ,lead or aluminum flashing. If flashing is rotted rusted or improperly installed water will run down the brick between the roof and the chimney saturating bricks from the side.

Thigs you can do to stop repoint with new mortar, fix chimney crown, replace with new bricks, waterproof chimney with a breathable water repellent never seal bricks need to breathe.