Chimney Flashing Repair in Seattle
Most chimney leaks start where the roof meets the chimney. Failed sealant, shifted step flashing, lifted counter flashing — small failures that let water into the attic and ceiling below. We diagnose the source and recommend the smallest scope that genuinely stops the water. Free roof-level inspection across Seattle.
NCSG Member
National Chimney Sweep Guild
Flashing Work We Do
- Sealant resealing & touch-up
- Step flashing replacement
- Counter flashing rework
- Reglet cuts into masonry
- Full flashing system replacement
- Roof-chimney junction inspection
Signs Your Flashing Is Failing
Flashing leaks often appear below the chimney — not at it
Water staining in the attic
Dark or yellow water stains on the attic rafters or roof sheathing near where the chimney passes through are one of the earliest signs of flashing failure. Water enters at the chimney junction and runs along the framing before reaching the ceiling.
Ceiling stains near the chimney
Brown or yellow stains on the ceiling around the chimney chase indicate water has traveled down through the wall or attic from the flashing leak above. Often appears after a heavy rain.
Leaks specifically after rain
If your chimney leaks only during or shortly after rain — and the firebox, crown, and cap all look intact — flashing failure is the most likely source. The water entered at the chimney-roof joint.
Damp chimney walls inside the home
Wet drywall, peeling paint, or soft spots on the wall surrounding the chimney chase indicate ongoing moisture. The water is usually entering above and migrating through the wall assembly.
Rusted or stained flashing
Visible rust on the chimney flashing from the ground or via roof inspection means the metal is corroding. Galvanized flashing rusts through within years in Pacific Northwest conditions — stainless or copper holds up much longer.
Cracked or pulled-away sealant
The sealant joint between counter flashing and brick eventually cracks, dries out, or pulls away from the masonry. Visible gaps along the top edge of the flashing are a clear indicator that resealing or replacement is needed.
Find the Actual Leak Source
Flashing Failures Stop Here
We diagnose where the water is actually entering — whether it's the sealant, counter flashing, step flashing, or underlying masonry — and fix the root cause, not just the symptom.
Get a Free Estimate →Key Decision
Flashing Repair vs. Flashing Replacement
Many chimney flashing leaks can be repaired without full replacement — which saves you significant scope. We assess condition first and recommend the smallest fix that genuinely stops the water.
Flashing Repair
Targeted Sealing & Sectional
When the flashing metal is still intact but sealant has failed, edges have lifted, or individual step flashing pieces have shifted, targeted repair restores function without disturbing the rest of the system. We reseal joints with proper masonry-grade sealant, re-bed counter flashing into a fresh reglet cut, and replace individual step flashing pieces as needed.
When it works:
- •Flashing metal is intact (no major corrosion)
- •Sealant has failed but metal is sound
- •Localized step flashing damage
- •Counter flashing has lifted but isn't damaged
Flashing Replacement
Full System Rebuild
When the flashing metal itself is corroded through, dented, or improperly installed from the start, replacement is the right answer. We remove the existing system, cut a proper reglet into the masonry, install new step flashing under each shingle course, and bed new counter flashing in fresh sealant.
When it's necessary:
- •Flashing metal has rusted or corroded through
- •Original installation was improperly done
- •Multiple leak sources across the system
- •Roof is being replaced anyway
Common pairing: When the roof itself is being replaced, we coordinate chimney flashing replacement with the roofing project. It costs significantly less to do them at the same time than to redo flashing after new shingles are down.
Trust & Honesty
Why Chimney Leaks Get Misdiagnosed
Not every chimney leak is a flashing problem. A leak that appears to be flashing-related is sometimes caused by the crown, the cap, the masonry, or even the roof itself. Misdiagnosing the source means paying to fix something that wasn't broken — while the real leak continues.
Our process: We inspect all five possible sources before recommending flashing work — flashing, crown, cap, masonry, and roof. If the leak isn't actually from the flashing, we tell you. We'd rather refer you to a roofer for a roof problem than sell you flashing repair that won't stop the leak.
Flashing
Failed sealant, shifted step flashing, or lifted counter flashing at the chimney-roof joint.
Crown
Cracks in the concrete cap at the top of the chimney letting water seep into the masonry below.
Cap
Missing or damaged chimney cap letting rain fall directly into the flue and damage components below.
Masonry
Deteriorated mortar joints or porous brick allowing water to migrate through the chimney wall itself.
Roof issue
Sometimes the leak isn't even a chimney problem — failed shingles, lifted vent boots, or damaged underlayment near the chimney.
Multiple sources
Often the real culprit is two or three of these failing at the same time. Effective repair addresses all the contributing sources.
The Basics
What Chimney Flashing Does
Chimney flashing is the metal sealing system at the joint where your chimney passes through the roof. It's not one piece — it's a layered system of step flashing and counter flashing working together to keep water out of the attic and ceiling below.
Why it's so often the leak source. The chimney and the roof expand and contract differently with temperature and weather. The flashing joint flexes constantly — and that constant movement is what eventually breaks sealant bonds, shifts metal pieces, and lifts counter flashing out of the masonry. This is normal wear, not poor workmanship.
Step flashing
Step flashing consists of small L-shaped metal pieces installed underneath each row of shingles where the roof meets the chimney. Each piece overlaps the one below, creating a stepped, watertight pattern that channels water down the slope of the roof.
Counter flashing
Counter flashing is the upper layer embedded into the chimney masonry (in a saw-cut channel called a reglet) and lapped down over the step flashing. It seals the top edge of the step flashing against the chimney brick.
Layered seal system
Together, step and counter flashing form a two-layer system. Water hitting the chimney runs down the masonry, hits the counter flashing, and is directed onto the step flashing — which then carries it onto the surrounding shingles.
Sealant joints
Sealant fills the small gaps in the layered system — especially where counter flashing meets brick and where step flashing meets the corner at the chimney. Sealant is the most common single point of failure.
Common Causes of Flashing Failure
Most flashing leaks are predictable failures rather than surprises
Poor original installation
Flashing that was installed without a proper reglet cut, used the wrong metal for the local climate, or relied entirely on sealant instead of layered flashing pieces — common on rushed or budget installations — fails years sooner than properly installed systems.
Shifting home & chimney structure
Foundations settle, framing flexes, masonry expands and contracts. The chimney and the roof move at slightly different rates, and over years the flexing fatigues the flashing — pulling counter flashing out of the reglet or lifting step flashing edges.
Failed sealant
Sealant has the shortest lifespan of any flashing component. Quality sealants last 10–15 years; budget sealants fail in 3–5. The sealant joint between counter flashing and brick is almost always the first thing to need resealing.
Corrosion of flashing metal
Galvanized flashing — common on older Pacific Northwest installations — rusts through over years. Aluminum flashing corrodes in marine air. Stainless steel and copper resist corrosion much longer but cost more upfront.
Storm damage
Pacific Northwest winter storms produce sustained winds that lift unsecured flashing edges, fracture brittle sealant, and dislodge step flashing pieces. Storm damage is one of the most common reasons we get called for emergency leak repair.
Aging roof system
When the roof itself is at end-of-life, the flashing usually is too — they aged together. Roof replacement is typically the right moment to also replace chimney flashing rather than leave aged flashing under new shingles.
Seattle Rain & Chimney Flashing Failure
Pacific Northwest climate is especially hard on chimney flashing systems — and we see the patterns across every Seattle neighborhood.
Sustained annual rainfall
Seattle's heavy rain finds any flashing weakness almost immediately. Small sealant cracks that would be inconsequential in drier climates become full leaks within a season here. Flashing is tested constantly.
Marine air corrosion
Salt particulates from Puget Sound accelerate corrosion on metal flashing components — especially on homes in West Seattle, Magnolia, Madrona, and other water-adjacent neighborhoods. Galvanized flashing rusts through years faster here than in inland Washington.
Freeze-thaw stress
Pacific Northwest winters cycle through freeze-thaw conditions repeatedly. Water in flashing seams freezes, expands, and forces apart sealant bonds and overlapping metal joints. Each winter compounds the previous one.
Wind & storm damage
Winter windstorms produce sustained gusts that lift unsecured flashing edges, fracture aged sealant, and dislodge step flashing pieces. We see a spike in flashing repair calls every January after the year's worst storms.
Older Seattle homes
Pre-1970 Seattle homes often have flashing that was installed decades before stainless steel became standard. Galvanized flashing on these homes has typically rusted through or failed multiple times — even with periodic repair.
Moss & biological growth
Seattle's damp climate promotes moss growth on roofs and around chimney flashing. Moss roots lift sealant edges, hold moisture against metal, and accelerate corrosion. Roof maintenance includes keeping chimney flashing clear of growth.
Chimney Flashing Repair FAQ
Questions Seattle homeowners ask before scheduling flashing repair
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Chimney Crown Repair
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Chimney Masonry Repair
Tuckpointing & brick restoration
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All chimney repair services
Get a Roof-Level Leak Inspection
We inspect all five possible leak sources — flashing, crown, cap, masonry, and roof — and recommend the smallest scope that genuinely stops the water. Free inspection across Seattle and the Puget Sound region.
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Last reviewed: May 2026