Boston sits on a glacial-till peninsula where granite ledge, tight lots, and 1850s brick row houses meet 1890s triple-deckers and steep Victorian gables. That mix of flat roofs, bay windows, chimney stacks, and dormers means every roof has at least one penetration, and every penetration is a potential leak. When snow melt and nor'easter rain arrive, Flashing, Chimney & Skylight Repair in Boston becomes the number one call we get. We bend flashing in-house for a precise watertight fit around chimneys, skylights, valleys, dormers, and brick transitions. If you are chasing a stain on a Back Bay ceiling or ice dam water in a Dorchester triple-decker, start with our metal roof leak repair page and we will trace it to the flashing.
Why Flashing, Chimney & Skylight Repair Matters on Boston's Dense, Snow-Loaded Roofs
Boston roofs take a beating that most flashing details were never sized for. Heavy snow loads sit for weeks, then daily freeze-thaw pushes meltwater sideways under chimney counterflashing and around skylight curbs. Salt air and humid summers corrode fasteners and thin-gauge flashing on copper bay windows and porch roofs. Nor'easters drive rain almost horizontally into seams and brick transitions. The failure mode that dominates here is ice dam back-up at chimney bases and low-slope roof-to-wall junctions on triple-deckers.
- Chimney flashing fails first when mortar joints open and step flashing pulls away from the brick.
- Skylight curbs on 1920s Colonials in West Roxbury and Quincy leak when the original curb flashing corrodes through.
- Valley flashing on steep Victorian gables in Jamaica Plain and Cambridge traps pine needles and backs up in a nor'easter.
- Dormer and bay window transitions on Beacon Hill and the South End wick water into brick when counterflashing is undersized.
- Low-slope roof-to-wall junctions on Somerville and Chelsea triple-deckers split when the building moves and the flashing does not.
Every one of these is a flashing problem before it is a roofing problem, and catching it early saves the deck and the ceiling below.
Key info: On a Back Bay row house, a failed chimney counterflashing can send water down the inside of a brick party wall for two floors before it shows. We have traced leaks from a third-floor ceiling to a chimney base flashing that had been patched with caulk three winters in a row.
For official guidance on roofing permits and inspection requirements, check the City of Boston Inspectional Services Department, and always confirm rules with your local building department since thresholds vary by jurisdiction.
How We Repair Flashing, Chimneys, and Skylights on Boston Roofs
We do not guess at a leak. We start on the roof, map the water path, and fabricate flashing to fit the actual penetration, not a stock piece from a box store. On older Boston stock, that means working around granite ledge setbacks, tight lot access, and brick that has moved since it was laid. Here is the sequence we follow on a typical job.
- We inspect the roof, attic, and interior ceiling to trace the leak to its actual entry point.
- We remove the failed flashing, counterflashing, and any rotted decking or sheathing underneath.
- We measure and bend new flashing in-house to match the chimney, curb, or wall transition.
- We install step flashing, counterflashing, and sealant in the correct sequence for the roof pitch.
- We water-test the repair and check the interior before we close out the job.
That sequence is the same whether we are on a copper bay window in Charlestown or a standing seam dormer in Newton, and it is why we rarely get a callback on a flashing repair.
Key info: A Somerville triple-decker had water staining a second-floor ceiling every January. The culprit was a skylight curb flashing that had been screwed through the top of the curb instead of behind it. We rebuilt the curb, bent new flashing, and the stain stopped that winter.
If the repair uncovers a bigger problem, we scope it against our metal roof repair service so you see the full picture before any work starts.
Flashing Repair Methods We Use Across Boston
Not every flashing problem calls for the same fix. The right method depends on the penetration type, the roof pitch, the metal already on the roof, and how much movement the building sees. Here is how we match the approach to the job.
| Approach | Description | Best for |
|---|---|---|
| Chimney counterflashing replacement | We cut new reglets into the brick and bend counterflashing to shed water away from the masonry. | Brick chimneys on Beacon Hill, the South End, and Back Bay row houses. |
| Skylight curb rebuild and flashing | We rebuild the curb, install new step and apron flashing, and seal the transition to the roof panel. | Leaking skylights on 1920s Colonials and Capes in Quincy, Milton, and Lexington. |
| Step and valley flashing fabrication | We bend step flashing and valley metal to match the pitch and panel profile on steep gables. | Victorian and Queen Anne roofs in Jamaica Plain, Roslindale, and Cambridge. |
| Wall and dormer transition flashing | We replace failed wall flashing and counterflashing where roofs meet brick, siding, or dormers. | Low-slope triple-deckers in Somerville, Chelsea, and Revere. |
| Copper and specialty metal flashing | We form copper flashing for bay windows, cupolas, and porch roofs that need a long service life. | Historic and waterfront buildings in Charlestown and the Seaport edge. |
We pick the method based on what the roof actually needs, and we tell you when a simpler fix will outlast a more expensive one.
Flashing, Chimney & Skylight Repair Cost in Boston: What to Expect
Most flashing repairs in Boston start at From $600 for a single chimney or skylight flashing replacement with straightforward access. From there, cost moves with the number of penetrations, the roof pitch and height, whether decking or brick needs repair, and the metal you choose (galvanized, aluminum, or copper). A steep Victorian gable in Cambridge with three dormers costs more than a flat triple-decker roof in Dorchester with one chimney. Getting two or three estimates is smart because flashing scope is easy to underbid and hard to compare line for line.
We break down what drives the number on our pricing page so you can see how a small repair grows into a larger one. Ice dam damage found in January often reveals rotted decking that was not visible in the fall, and that changes the scope.
Key info: A Brookline homeowner got three quotes for a skylight leak. Two were patch jobs under $500. The third pulled the curb and found rotted sheathing. The patch jobs would have failed by the next thaw, which is why we show you photos before we quote.
What to Look for in a Metal Roofing Contractor Near Boston
Flashing work is detail work, and the contractor you hire matters more than the material. Ask for proof of licensing and insurance before anyone gets on the roof, and get the certificate sent to you directly from the insurer. Get at least two or three written estimates that describe the flashing method, not just a price. Ask for references from jobs in your neighborhood and call them. If your building is in a historic district or under HOA design review, confirm the contractor has pulled permits for similar work and understands the review process. Then check the quote against the scope, because the cheapest flashing job is often the one that leaks first.
You can reach us through our contact page to schedule an inspection and get a written scope before you decide.
Flashing, Chimney & Skylight Repair in Boston: Pricing Guide
| Service | Price | Details |
|---|---|---|
| Chimney flashing repair | Starting at $600 | Includes counterflashing replacement and reglet cutting on a standard brick chimney with roof access. |
| Skylight flashing repair | Starting at $750 | Includes curb inspection and new step and apron flashing; rotted curb or decking moves the price up. |
| Valley or step flashing | Starting at $650 | Includes removal and in-house bending of step or valley metal on a standard pitch roof. |
| Multiple penetrations or steep access | On estimate | Jobs with three or more penetrations, steep gables, or tight lot access need an on-site look first. |
| Travel | Included | In Boston and surrounding areas, no separate call-out or mileage fee. |
| Estimate | Free | Response within 24h at (857) 465-5405, no obligation to book. |
Indicative pricing, the exact cost depends on square footage, finish, and site access. Free personalized estimate within 24h at (857) 465-5405.
