Chimney Flashing Repair: Why Coastal Home Chimneys Leak and How to Fix (2026)

What Chimney Flashing Is: Step, Counter, and Cricket

Chimney flashing is not a single piece of metal. It is a system of overlapping components that work together to channel water around the chimney and back onto the roof surface below. Each component has a specific job, and a failure in any one of them can let water into your home. Understanding the three main components helps you understand what is failing when a leak develops.

Step Flashing

Step flashing runs along each side of the chimney where it meets the sloped roof surface. It consists of individual L-shaped metal pieces, each one woven between successive shingle courses and bent up against the chimney wall. The pieces overlap each other like shingles, creating a stair-step pattern that channels water sideways and downhill rather than letting it run down the chimney-to-roof joint.

Step flashing is the workhorse of the chimney flashing system. Each piece typically measures 4 by 4 inches when bent, with about 2 inches running up the chimney wall and 2 inches running under the shingles. Proper installation means each piece overlaps the one below it by at least 2 inches, creating a continuous water barrier. When step flashing fails — either from corrosion, lifting, or improper installation — water runs down the chimney wall and under the shingles rather than being channeled onto the roof surface.

Counter Flashing

Counter flashing is the second layer that covers the top edge of the step flashing. It is embedded directly into the chimney mortar joints — the horizontal seams between courses of brick or stone. The mortar joint is cut out (called a reglet), the counter flashing is inserted into the cut, and fresh mortar or sealant secures it in place. The counter flashing then bends downward over the top of the step flashing, creating an overlapping seal.

This two-layer system — step flashing underneath, counter flashing on top — is what makes chimney flashing effective. Water hitting the chimney wall runs down the counter flashing, drips onto the step flashing, and is channeled onto the roof surface. The critical detail is the mortar joint. If the sealant holding the counter flashing in the reglet fails, the top edge lifts away from the chimney, and water runs behind both the counter flashing and the step flashing. This is the single most common chimney flashing failure point.

Chimney Cricket (Saddle)

The chimney cricket is a small peaked structure built on the upslope side of the chimney — the side where water and debris flow toward the chimney from above. It looks like a miniature roof ridge behind the chimney, and its job is to divert water and debris to either side of the chimney rather than allowing it to pool against the back wall.

Without a cricket, the back wall of the chimney acts like a dam. Water flowing down the roof hits the chimney and pools behind it. Leaves, pine needles, and granules from the shingles accumulate in that pool, creating a debris dam that holds water against the flashing for extended periods. In Myrtle Beach, with live oaks and pine trees shedding year-round, the debris accumulation behind an uncricketed chimney can be several inches deep. That standing water is the most destructive force acting on chimney flashing. A properly built cricket eliminates the pooling entirely.

Why Coastal Chimneys Fail Faster

A chimney flashing system installed in Greenville or Charlotte will outlast the same system in Myrtle Beach by a wide margin. The coast introduces four specific forces that accelerate flashing failure, and they compound each other.

Salt Air Corrodes Metal Flashing

Homes within 5 miles of the Atlantic Ocean sit in an active salt corrosion zone. Airborne salt deposits on metal surfaces and accelerates oxidation. Standard galvanized steel flashing — the most common flashing material in residential construction — develops corrosion pitting within 8 to 12 years in this zone compared to 20+ years inland. The corrosion eats through the protective zinc coating, exposing the base steel, which then rusts rapidly. The rust creates pinholes and weakens the metal at fold lines and overlaps where water concentrates. At fastener locations, galvanic corrosion between dissimilar metals (galvanized nail in aluminum flashing, or stainless screw in galvanized flashing) accelerates the failure further.

Thermal Cycling Cracks Sealant and Loosens Joints

A chimney on a Myrtle Beach roof experiences extreme temperature swings. In summer, the roof surface can reach 160°F or higher on a dark shingle, while the masonry chimney stays cooler because brick has higher thermal mass. In winter, the metal flashing can drop to 28°F overnight and warm to 65°F by midday.

The critical problem is that metal, masonry, and sealant expand and contract at different rates. Metal flashing moves significantly with temperature changes. Brick barely moves. The sealant bridging the gap between them gets stretched and compressed with every thermal cycle. Over thousands of cycles — roughly 365 per year, twice or more per day in summer — the sealant fatigues, cracks, and pulls away from one or both surfaces. This is why you can reseal chimney flashing and have the sealant fail again within 5 to 8 years in coastal conditions. The thermal movement never stops.

Wind-Driven Rain Exploits Gaps

Chimney flashing is designed to handle rain falling vertically. During tropical storms, northeasters, and strong coastal thunderstorms, rain moves horizontally or even upward under overhangs and flashing edges, driven by 50 to 100 mph wind gusts. Water reaches places it was never designed to go. A counter flashing joint that stays bone dry during a normal afternoon thunderstorm can leak heavily during a tropical storm because the wind pushes water uphill and behind the counter flashing. Coastal homes experience these conditions 3 to 6 times per year. Inland homes may experience them once in a decade. This is why chimney flashing that looks fine to a visual inspection can still leak — the failure only reveals itself under wind-driven rain conditions.

Foundation Settling from Sandy Soil Shifts the Chimney

This is the factor unique to coastal South Carolina that most articles on chimney flashing miss entirely. The Grand Strand is built on sandy soil with a high water table. Sandy soil is more prone to differential settling than the clay soils found inland. Over time, the chimney — which has its own footing separate from the house foundation — can settle at a different rate than the rest of the structure. Even a quarter inch of differential movement between the chimney and the roof framing opens gaps in the flashing system that no amount of sealant can permanently bridge. This is why some coastal chimneys develop chronic leaks that keep coming back after repair — the underlying cause is structural movement, not just material failure.

• Salt air corrosion — galvanized steel flashing develops pitting in 8 to 12 years vs 20+ years inland
• Thermal cycling — sealant fatigues from hundreds of expansion-contraction cycles per year
• Wind-driven rain — 3 to 6 events per year push water into joints that stay dry during normal rain
• Sandy soil settling — differential movement between chimney footing and house foundation opens flashing gaps
• High humidity — 75 to 85 percent average humidity slows drying of any moisture that enters behind flashing, accelerating rot

Types of Chimney Flashing Failure

Every chimney leak I have diagnosed on the Grand Strand traces back to one of these four failure modes. Identifying which one is causing your leak determines the right repair and whether a targeted fix or full reflash is the better investment.

1. Lifted Counter Flashing

Counter flashing lifts when the sealant or mortar holding it in the chimney reglet fails. The top edge pulls away from the chimney wall, creating a gap that lets water run behind both the counter flashing and the step flashing underneath. This is the most common chimney flashing failure and the easiest to spot — you can often see daylight between the counter flashing and the chimney brickwork. In coastal conditions, the sealant in the reglet typically lasts 8 to 12 years before thermal cycling causes it to crack and release. The fix for lifted counter flashing involves re-cutting the reglet if needed, reseating the counter flashing, and applying fresh sealant rated for the temperature range and UV exposure of a coastal roof.

2. Cracked or Failed Sealant

Sealant fills the gaps between metal flashing pieces, between flashing and masonry, and between flashing and shingles. It is the weakest link in the chimney flashing system because it degrades faster than metal or masonry. In coastal South Carolina, roofing sealant lasts 8 to 12 years before UV exposure and thermal movement cause it to crack, dry out, and separate from bonded surfaces. The cracks may be hairline-thin, but wind-driven rain needs almost nothing to enter. Cracked sealant is easy to diagnose on inspection and relatively inexpensive to repair — provided the underlying metal flashing is still sound. If the sealant is failing because the metal is corroded or deformed, resealing alone is a temporary fix.

3. Corroded Step Flashing

Step flashing corrodes from the bottom up — the underside that sits against the roof deck and behind shingles stays damp longer than the exposed surface, and moisture accelerates corrosion from below. On the coast, salt deposits on the exposed surface accelerate corrosion from above simultaneously. The result is flashing that looks acceptable on visual inspection but has thinned and developed pinholes at the fold line where the vertical leg meets the horizontal leg. Those pinholes let water seep through the flashing itself, bypassing the overlap system entirely. Corroded step flashing cannot be resealed — it must be replaced. This is a more involved repair because the surrounding shingles must be lifted or removed to access and replace each step flashing piece.

4. Missing or Deteriorated Cricket

Many older homes along the Grand Strand were built without a chimney cricket, or the original cricket has deteriorated to the point that it no longer diverts water effectively. Without a functional cricket, water and debris accumulate behind the chimney after every rain. That pooling water sits against the rear flashing for hours or days, soaking through sealant joints and accelerating corrosion. Even if the side flashing is in good condition, a missing cricket causes the rear flashing to fail years ahead of the rest of the system. Adding a cricket to an existing chimney is one of the most impactful chimney leak repairs because it addresses the root cause — water pooling — rather than just patching the symptom.

Signs Your Chimney Flashing Is Failing

Chimney flashing failure does not happen all at once. It develops over months or years, and the early warning signs are easy to miss if you do not know what to look for. These three indicators are the most reliable signals that your chimney flashing needs attention.

Water Stains on the Ceiling Near the Chimney

This is the most common sign and the one that brings most homeowners to call a roofer. A brown or yellowish stain on the ceiling adjacent to the chimney — especially one that appears or darkens after rain — means water is entering around the chimney and traveling along the framing or decking to the ceiling below. The stain location does not always correspond to the flashing failure point because water can travel several feet along a rafter or joist before dripping onto the drywall. But a ceiling stain within 3 to 4 feet of the chimney almost always traces back to a chimney flashing issue.

Stains or Moisture on the Interior Chimney Wall

Water stains, dampness, or peeling paint on the chimney wall inside the house — in the attic or in the room where the chimney is exposed — indicate water is entering at the flashing-to-chimney joint and running down the masonry. Unlike a cap or crown leak that sends water down the flue, a flashing leak sends water down the exterior face of the chimney behind the flashing, where it migrates inward through the masonry. The stains typically appear on the upslope side of the chimney — the side facing the ridge — because that is where water pressure against the flashing is greatest.

Efflorescence on Exterior Brickwork

Efflorescence is the white, powdery, crystalline deposit that appears on the surface of brickwork. It forms when water migrates through the masonry, dissolving mineral salts in the brick and mortar, and deposits those salts on the surface as it evaporates. Efflorescence near the roofline — particularly on the sides of the chimney where flashing meets brick — is a strong indicator that water is entering at the flashing joint and migrating through the masonry. While efflorescence itself is cosmetic, the water movement it reveals is not. Persistent water migration through masonry degrades the mortar joints, and in freeze-thaw cycles, can cause spalling (surface cracking and flaking) of the brick itself.

Chimney Flashing Repair Options and Costs

The right repair depends on what is actually failing. Here are the four tiers of chimney flashing repair, from least invasive to most comprehensive.

Tier 1: Reseal — $150 to $400

Resealing involves removing old, failed sealant from the flashing joints and counter flashing reglet, cleaning the surfaces, and applying fresh high-quality roofing sealant. This is the appropriate repair when the metal flashing itself is in good condition — no corrosion, no deformation, no missing pieces — but the sealant between components has cracked or separated.

Resealing is effective when the leak is at a sealant joint rather than a metal failure, the flashing metal shows no corrosion or pitting, and the counter flashing is still properly seated in the reglet. In coastal conditions, a professional reseal using polyurethane sealant rated for UV and thermal cycling lasts 5 to 8 years before the sealant needs refreshing again. This is the lowest-cost option and the right starting point for chimneys with relatively new flashing that has only sealant failure.

Tier 2: Replace Step Flashing — $300 to $700

Replacing step flashing involves lifting or removing the shingles adjacent to the chimney, removing the corroded or damaged step flashing pieces, installing new step flashing woven into the shingle courses, and reinstalling the shingles. The counter flashing may or may not need replacement depending on its condition.

This is the right repair when the step flashing has corroded through, is missing pieces, or was improperly installed originally. The cost depends on how many sides of the chimney need new step flashing and whether the surrounding shingles can be reused or need replacement. Replacing step flashing on one side of a standard chimney typically runs $300 to $500. Both sides push the cost to $500 to $700. If the surrounding shingles are brittle or damaged from age, new shingles for the affected area add $100 to $200.

Tier 3: Full Reflash — $500 to $1,200

A full reflash means replacing every component of the chimney flashing system — step flashing on both sides, counter flashing on all faces, apron flashing at the base, and all sealant. The surrounding shingles are removed and reinstalled (or replaced if damaged). The counter flashing reglets are re-cut in the mortar joints if needed, and new counter flashing is installed and sealed.

Full reflash is the right call when multiple components are failing simultaneously, when the flashing is over 15 years old in coastal conditions, or when a previous partial repair failed to stop the leak. The cost depends on chimney size, flashing material choice, and roof type. A standard single-flue chimney on a shingle roof typically runs $500 to $800 for a full reflash with aluminum. Using copper flashing pushes the cost to $800 to $1,200 but provides significantly longer service life. On a metal roof, the cost runs higher because the metal panels require more careful work to maintain weather-tight seams.

Tier 4: Add Chimney Cricket — $400 to $800

Adding a chimney cricket to an existing chimney involves building a small framed structure on the upslope side of the chimney, sheathing it with plywood, installing underlayment and flashing, and integrating it with the surrounding roof surface. The cricket itself is simple construction — two sloped planes meeting at a ridge that diverts water to either side of the chimney. The cost includes framing, sheathing, underlayment, metal capping or shingles, and the flashing that ties the cricket to both the chimney and the surrounding roof. If the cricket is being added during a full reflash or roof replacement, the cost is lower because the area is already opened up. As a standalone project, expect $400 to $800.

Flashing Material Choices for Coastal Homes

The flashing material you choose determines how long the system lasts in salt air. This is where cutting costs upfront leads to expensive repairs later. Here is how the four common flashing materials perform in coastal South Carolina conditions.

Copper — The Gold Standard for Coastal

Copper is the best chimney flashing material for any home within 10 miles of the ocean. It does not corrode in salt air — instead, it develops a green patina (verdigris) that actually protects the underlying metal. Copper lasts 50 years or more, solders easily for watertight joints, and becomes more attractive with age. The drawback is cost: copper flashing material costs 3 to 4 times more than aluminum. But when you factor in the 50+ year lifespan versus 15 to 25 years for aluminum, copper is less expensive per year of service. For a home you plan to keep for decades, copper chimney flashing is the best investment. For a full chimney reflash, copper adds roughly $200 to $400 to the project cost compared to aluminum.

Lead-Coated Copper — Premium Alternative

Lead-coated copper combines the corrosion resistance of copper with a matte gray finish that is less visually prominent than the bright copper appearance (before patina develops). It resists salt air just as well as bare copper, lasts 40 to 50 years, and solders easily. Lead-coated copper is the traditional choice for high-end residential and historic buildings. The lead coating also provides a sacrificial layer that protects the copper underneath from the abrasive action of sand and debris washing over the flashing surface. Cost is similar to or slightly higher than bare copper. Some homeowners prefer it for the neutral appearance on brick chimneys.

Aluminum — Budget Coastal Option

Aluminum resists salt air corrosion significantly better than galvanized steel, making it the acceptable budget option for coastal chimney flashing. It lasts 15 to 25 years in salt air, is widely available, and is the standard material used by most roofing contractors. The limitation of aluminum is that it cannot be soldered — joints must be sealed with sealant or mechanical fasteners, and those sealant joints are the first point of failure. In coastal conditions where sealant lasts 8 to 12 years, aluminum flashing often needs its first reseal before the metal itself shows any sign of failure. Aluminum is the right choice when budget is a primary concern, but expect to reseal the joints at least once during the flashing lifespan.

Galvanized Steel — Avoid for Coastal

Galvanized steel is the most common flashing material in residential construction nationwide, but it is the worst choice for coastal chimneys. The zinc coating that protects galvanized steel breaks down rapidly in salt air, and once the zinc is gone, the base steel rusts aggressively. In the Myrtle Beach salt corrosion zone, galvanized chimney flashing typically develops visible corrosion within 8 to 12 years and can fail completely by 15 years. If your home currently has galvanized chimney flashing and it is approaching 10 years old, proactive replacement with copper or aluminum before it fails will save you from water damage repair costs.

The Chimney Cricket: When You Need One and Why

The chimney cricket is the most underappreciated component in the chimney flashing system, and its absence is behind a significant number of the chronic chimney leaks I see on the Grand Strand. Understanding when a cricket is required and why it matters will help you make the right repair decision.

When Code Requires a Cricket

The International Residential Code (IRC) requires a chimney cricket on any chimney that is more than 30 inches wide on the upslope side of the roof. This applies to new construction and major renovations. Many homes built before this code provision was widely adopted — or homes where the chimney was narrowly under the 30-inch threshold — do not have crickets. If your chimney is 30 inches or wider on the upslope dimension and does not have a cricket, it is technically a code deficiency, and it is actively contributing to premature flashing failure.

Why Crickets Matter Even Below 30 Inches

Code sets a minimum. Best practice goes further. Even a chimney that is only 20 to 24 inches wide benefits substantially from a cricket in coastal South Carolina. The reason is that any chimney, regardless of width, creates a dam on the roof that collects water and debris. A 24-inch chimney on a 6/12 pitch roof still accumulates enough water behind it during a heavy rain to stress the rear flashing. Add in the pine needles, live oak leaves, and shingle granules that accumulate against the chimney back wall, and the debris dam can hold standing water for days between rains. A cricket eliminates that pooling for $400 to $800 — a fraction of the cost of the water damage it prevents.

Chimney Flashing and Roof Replacement

If you are planning a roof replacement, the chimney flashing question is straightforward: always reflash during a reroof. There is no scenario where reusing old chimney flashing on a new roof makes sense.

Why You Must Reflash During a Reroof

The step flashing is woven between individual shingle courses. When the old shingles are removed, the step flashing comes with them — or at minimum, is exposed and disturbed. Reinstalling the same step flashing into new shingle courses means using metal that has already been through years of thermal cycling, may have hidden corrosion on the underside, and has been bent and stressed during removal.

More importantly, a new roof is expected to last 25 to 30 years (architectural shingles) or 40 to 60 years (standing seam metal). Old flashing on a new roof creates a weak point that will likely fail years before the new roofing material. When it does, repairing it means disturbing the new shingles around the chimney — a repair that would have been unnecessary if the flashing was replaced during the original reroof.

What Reflashing During a Reroof Should Include

• New step flashing on all sides, woven into the new shingle courses
• New counter flashing — either new metal installed in re-cut reglets, or existing counter flashing reseated and sealed if it is copper or lead-coated and still in good condition
• New apron flashing at the base of the chimney
• Chimney cricket — added if one does not exist and the chimney is 30 inches or wider (or recommended for any chimney in a heavy debris area)
• Ice and water shield membrane under the flashing for an additional waterproofing layer
• Fresh sealant at all joints, using polyurethane rated for UV and thermal cycling

David Karimi / WeatherShield Approach

When a homeowner calls us about a chimney leak, we follow a specific diagnostic process to identify the actual failure point before recommending any repair. Chimney leaks can originate from the flashing, the chimney cap, the crown, deteriorated mortar joints, or condensation inside the flue. Throwing sealant at the problem without identifying the source wastes money and leaves the real issue unresolved.

We do not sell full reflash jobs when a $300 reseal will solve the problem. And we do not sell $300 reseals when the flashing is corroded and needs replacement — because that would mean coming back in a year to do the reflash we should have recommended the first time. Honest diagnosis leads to the right repair the first time.

We serve homeowners throughout Myrtle Beach, Conway, North Myrtle Beach, Surfside Beach, Pawleys Island, Murrells Inlet, and the surrounding Horry and Georgetown county areas.

Frequently Asked Questions