How Much Does Chimney Flashing Repair Cost? (2026 Guide)
Chimney flashing repair costs $300 to $1,200 for most homes. Resealing the counter-flashing joint runs $150–$400; replacing step and counter-flashing properly — cut into the mortar joints — runs $600–$1,800. Flashing is the single most common cause of a leaking chimney, and roofing tar is the single most common thing that makes it worse.
Chimney flashing repair cost by scope
| Repair | What it involves | Typical cost |
|---|---|---|
| Reseal the joint | New sealant at the counter-flashing top edge | $150–$400 |
| Partial re-flash | Replacing failed sections; rest is sound | $300–$700 |
| Full step + counter-flashing | New two-part system cut into the mortar joints | $600–$1,800 |
| Remove old roofing tar first | Stripping tar and repairing joints beneath | +$150–$400 |
| Copper flashing | Premium material; period-appropriate, long life | $1,000–$3,000 |
| Cricket / saddle installation | Diverter behind a wide chimney | $500–$2,000 |
| With shingle repair | Where the surrounding roof is damaged too | +$200–$800 |
Ranges reflect the Syracuse and Onondaga County market in 2026. Roof pitch, chimney width, and whether the mortar joints need repair before counter-flashing can be set are the main variables.
How flashing actually works
Worth understanding, because it explains why the cheap fix fails and the proper one costs what it does.
Where a chimney passes through a roof there is a permanent joint between two materials that move independently, expand at different rates, and are both trying to shed water. Flashing manages that joint, and a correct installation is two separate parts.
- Step flashing — L-shaped pieces of metal woven into the shingle courses as they run up alongside the chimney, so each piece laps over the one below.
- Counter-flashing — a second layer set into a groove cut into the chimney's mortar joints and folded down over the step flashing, so water running down the masonry is directed out onto the roof rather than behind the step flashing.
The two-part design exists specifically so the chimney and roof can move relative to each other without opening a gap. A single-layer flashing, or one sealed to the brick face rather than cut into a joint, cannot accommodate that movement — which is why it fails.
Why roofing tar is not a repair
This is the most common thing homeowners find when they finally get on the roof, and it is worth being blunt about.
Roofing tar around a chimney stops a leak for a season or two. Then it hardens, cracks, and — because it bridges the joint rather than shedding water away from it — traps moisture against the mortar behind it. Removing tar routinely reveals mortar joints that have been sitting wet and are now badly deteriorated, which means the eventual proper repair costs more than it would have before the tar went on.
It is the standard emergency fix, and as an emergency fix it is defensible — stopping water today while you arrange a proper repair is reasonable. What is not reasonable is leaving it there as the repair, which is what usually happens.
If you find tar around your chimney, assume the mortar joints underneath need inspecting, and budget for the strip-and-repair line ($150–$400) on top of the flashing itself. It is a common surprise on homes where the roof was replaced by someone who treated the chimney as an obstacle rather than a detail.
The five ways flashing fails
- Sealant at the top edge dries out and cracks. The most common, and the shortest-lived component of the whole assembly. This is the $150–$400 reseal.
- Counter-flashing pulls out of the mortar joint as the joint itself deteriorates. Needs the joint repaired and the flashing reset.
- Metal corrodes, particularly where galvanized was used rather than aluminium or copper.
- There was never any counter-flashing — just a bead of tar. Common on older homes and after cheap reroofs.
- The roof was replaced and the flashing was not. Reusing old flashing under new shingles is a false economy that surfaces two winters later.
Flashing vs. the other four leak causes
A leaking chimney has five possible causes and they look identical from inside the house. Getting this wrong means paying for a repair that does not stop the leak, then paying again.
| Cause | Where the stain appears | Typical repair cost |
|---|---|---|
| Failed flashing | At the ceiling, right where the chimney passes through | $300–$1,200 |
| Missing or failed cap | Water in the firebox; rust on the damper | $175–$400 |
| Cracked crown | Lower down the chimney breast; diffuse damp | $250–$2,500 |
| Porous masonry | Diffuse dampness with white efflorescence | $300–$900 |
| Flue condensation | Inside the firebox, cold weather only | $1,500–$5,000 |
More than one at a time is common — a cracked crown and failed flashing frequently arrive together, because the same freeze-thaw cycling drives both.
Why Syracuse chimneys leak in winter specifically
If your chimney leaks in February but not in a summer downpour, the cause is almost certainly ice dams — and this is a Central New York specialty.
A roof here carries snow load for months. Where heat escapes into the attic, the underside of that snowpack melts. The meltwater runs down to the cold eave, refreezes, and builds a dam — and water then backs up behind it, uphill, under the shingles.
A chimney sits directly in the path of that. Water moving under the shingle course reaches the flashing from beneath and behind, which is the one direction flashing is not designed to resist. This is why a flashing detail that handles rain perfectly well for twenty years can leak every winter, and why the fix sometimes involves attic insulation and ventilation as much as the flashing itself.
The other local factor is freeze-thaw on the mortar groove. Counter-flashing is set into a cut in the mortar joints, and every freeze cycle works at that joint. Over enough winters the counter-flashing loosens and pulls free — which is a masonry failure presenting as a roofing problem.
Does a chimney need a cricket?
Sometimes, and it is worth knowing about because it is a genuine solution rather than an upsell.
A cricket — also called a saddle — is a small peaked structure built on the up-slope side of a chimney to divert water and snow around it rather than letting it pile against the back face. On a wide chimney, particularly on a lower-pitched roof, the up-slope side collects debris and holds snow, and that standing load is exactly what drives water behind the flashing.
Building codes generally require a cricket above a certain chimney width, and it costs $500 to $2,000. If you have a wide chimney that leaks repeatedly on the up-slope side despite the flashing being replaced, this is the question to ask.
For the full diagnostic sequence on a leaking chimney, see the chimney leak repair service page.
Get an exact number for your situation
Every range on this page is a range, not a quote — the only way to get a real number is for someone to look at what you actually have. Our on-site assessment across Syracuse + Onondaga County, NY is free and produces a written scope and price before any work starts. Call (315) 803-6759, 24/7.
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Answers
Frequently asked questions
How much does chimney flashing repair cost?
Between $300 and $1,200 for most homes. Resealing the counter-flashing joint runs $150 to $400. Replacing step and counter-flashing properly, cut into the mortar joints, runs $600 to $1,800. Copper flashing is $1,000 to $3,000. Removing old roofing tar and repairing the mortar joints underneath adds $150 to $400.
Can I use roofing tar to seal around my chimney?
As a temporary emergency measure, yes. As a repair, no — it hardens and cracks within a season or two, and because it bridges the joint rather than shedding water away from it, it traps moisture against the mortar behind. Removing tar routinely reveals badly deteriorated joints, which makes the eventual proper repair more expensive than it would have been.
How do I know if my chimney leak is the flashing?
Where the stain appears is the strongest indicator. Flashing failures show up at the ceiling right where the chimney passes through the roof plane. A cracked crown lets water into the masonry above that, so the damp appears lower down the chimney breast or as diffuse staining. Water inside the firebox points to the cap instead. All three together is not unusual.
Why does my chimney only leak in winter?
Ice dams, almost certainly. Snow on the roof melts from below where heat escapes the attic, the meltwater refreezes at the cold eave and builds a dam, and water backs up under the shingles — reaching the flashing from beneath and behind, the one direction it cannot resist. In Central New York this is common enough that a flashing detail which handles rain fine for twenty years can still leak every February.
Should the flashing be replaced when I get a new roof?
Yes, and reusing old flashing is a false economy that surfaces two winters later. It is also the cheapest possible moment to do it properly — the roofer is already there, the shingles are already off, and step flashing has to be woven into the courses as they go on. Ask explicitly, because "we'll reuse the flashing" is a common way to shave a roofing quote.
What is a chimney cricket and do I need one?
A small peaked structure built on the up-slope side of a chimney to divert water and snow around it rather than letting it pile against the back face. Codes generally require one above a certain chimney width. It costs $500 to $2,000 and it is the right question to ask if you have a wide chimney that keeps leaking on the up-slope side despite the flashing having been replaced.
How long should chimney flashing last?
The metal itself should last as long as the roof — 20 to 30 years for aluminium or galvanized, considerably longer for copper. The sealant at the top edge of the counter-flashing is the short-lived component and typically needs renewing every 5 to 10 years. That $150 to $400 reseal is what prevents the $600 to $1,800 replacement.
Is chimney flashing a roofer or a chimney company job?
Either can do it, and the honest answer is that it depends on the failure. If the metal has corroded or the shingles need lifting, that is roofing work. If the counter-flashing has pulled out because the mortar joints have deteriorated, the masonry needs repairing before any flashing will hold — which is a chimney job. A company that only does one half will tend to diagnose it as the half they do.