Chimney Flashing Repair & Installation: Stop Leaks at the Source
Chimney flashing is the layered metal that seals the joint where your chimney meets the roof. It is one of the most common leak points on any house, because water, heat, and movement all meet at that joint. Failed flashing is often the real cause of a chimney leak, and it is a job for roofers near me with real flashing experience, not just a tube of caulk.
The parts of chimney flashing
Proper chimney flashing is a system, not a single piece. Each part handles a different side of the chimney, and a leak usually means one part has failed.
| Part | Where it goes | What it does |
|---|---|---|
| Base (apron) flashing | Along the low side of the chimney, where the roof slopes toward it | Directs water around the front of the chimney and onto the shingles |
| Step flashing | Along the sides, woven in with each course of shingles | Seals the side joints as the roof rises past the chimney |
| Counter (cap) flashing | Set into the mortar joints or a cut groove, folded down over the base and step pieces | Covers the top edge of the lower flashing so water cannot get behind it |
| Back flashing and cricket | On the high side of the chimney | Splits water and diverts it around the chimney instead of pooling behind it |
Cricket tip: A cricket (also called a saddle) is a small peaked structure behind the chimney. Building codes commonly require one when the chimney is more than about 30 inches wide, so ask your roofer to confirm what your local code requires.
Signs your chimney flashing is failing
Chimney leaks often show up far from the chimney. Check these signs, and have a roofer inspect the roof itself rather than climbing up yourself.
| What you notice | Likely cause | Urgency |
|---|---|---|
| Water stains on the ceiling or wall near the chimney | Leaking base or step flashing, or a missing cricket | Call within days |
| Wet or stained attic wood next to the chimney | Flashing gap or failed sealant letting water in | Call within days |
| Rust, gaps, or lifted metal at the chimney base | Aged flashing that has corroded or pulled away | Schedule soon |
| Cracked, dried, or tar-patched sealant | Past patch jobs failing. Sealant alone is not a lasting fix. | Schedule soon |
| Crumbling mortar or loose bricks | Masonry damage that can also let water behind the counter flashing | Inspect soon, may need a mason |
| Active dripping near the fireplace | Flashing failure, a cracked crown, or a flue problem | Same day. Avoid using the fireplace until checked. |
Chimney flashing repair vs. replacement costs
A small repair can be worth doing, but patching old flashing again and again rarely lasts. If the flashing is rusted, loose, or built wrong, replacing it costs more now and saves money later.
| Job | What is involved | Typical cost |
|---|---|---|
| Minor flashing repair | Re-seal or re-secure a small section, replace a few shingles | $200 – $600 |
| Partial flashing replacement | Replace one side or the base flashing | $400 – $1,000 |
| Full chimney flashing replacementMost lasting | Remove and rebuild all base, step, and counter flashing | $600 – $2,000 |
| Add or rebuild a cricket | Frame and flash a cricket behind the chimney | $500 – $1,500 |
| Tuckpointing for counter flashing | Repair mortar or cut a new groove for the counter flashing | $250 – $1,000+ |
| Flashing during a roof replacement | Usually replaced as part of the roof job | Often included in the roof quote |
Estimated 2026 national ranges for a licensed roofer, including labor. Large chimneys, steep or tall roofs, and masonry work raise the price. If the roof is near the end of its life, ask for a repair-versus-replacement quote, since new flashing will be redone with the roof anyway.
Best materials for chimney flashing
The metal you choose affects how long the repair lasts. Match the flashing metal to your roof and climate, and avoid mixing metals that corrode each other.
| Material | Typical lifespan | Relative cost | Notes |
|---|---|---|---|
| Galvanized steelCommon | 15 – 30 yrs | $ | Affordable and widely used. Can rust once the coating wears, especially near the coast. |
| Aluminum | 20 – 30 yrs | $ | Lightweight and rustproof, but can corrode against masonry, so it needs coating or separation. |
| Stainless steel | 30 – 50+ yrs | $$ | Strong and corrosion-resistant. Good for coastal or harsh climates. |
| Copper | 50 – 100 yrs | $$$ | Premium, long-lasting, and develops a green patina. Do not pair with aluminum or galvanized parts. |
| Lead-coated copper | 50+ yrs | $$$ | Very durable and flexible. Often used on historic and high-end homes. |
A word on sealants: Roofing cement and caulk can be a short-term patch, but they dry and crack as the chimney and roof move. Lasting repairs use properly layered metal flashing, with sealant only as a backup.
Is your whole roof aging too?
Run the Rooferus cost calculator to see what a full replacement would cost, then compare it against repair quotes from roofing companies near you.
How chimney flashing installation works
A proper job takes more than a day of careful work in many cases. Knowing the steps helps you spot a rushed or shortcut job.
- Inspect and diagnose The roofer checks the flashing, shingles, mortar, chimney crown, and attic to confirm flashing is the real source of the leak.
- Remove old flashing and shingles around the chimney Old metal and failed sealant come out, and any wet or rotted decking is repaired.
- Install base and step flashing The base piece goes in first, then step pieces are woven in with each shingle course so water always flows over the joint.
- Install counter flashing Counter flashing is set into the mortar joints or a cut groove and folded over the lower flashing, then sealed.
- Add or rebuild a cricket if needed A cricket is framed and flashed behind wider chimneys so water cannot pool on the high side.
- Seal, clean up, and test Final sealing, a cleanup of nails and debris, and a check that water runs clear of the chimney.
How to choose roofing companies near me for chimney flashing
Flashing is detail work, and shortcuts show up as repeat leaks. The best roofers near you will explain exactly how they flash each side of the chimney.
| Ask or check | Good sign | Red flag |
|---|---|---|
| Method | Describes base, step, and counter flashing, and how counter flashing is set into the masonry | Plans to smear sealant or roofing cement over the old flashing |
| Materials | Names the metal and thickness, and avoids mixing metals that corrode | Will not say what metal is being used |
| Masonry | Checks mortar and crown, or brings in a mason when needed | Ignores crumbling mortar or a cracked crown |
| License and insurance | Valid license plus liability and workers compensation on request | Cash only, no paperwork |
| Estimate and warranty | Written, itemized, with a workmanship warranty | Verbal quote or a large upfront deposit |
Chimney flashing questions, answered
Chimney leaking? Get it flashed right.
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