Chimney leaks are the most common roofing problem in Boston's historic homes — and the most frequently misdiagnosed. Most chimney leaks are not caused by the roof surface itself, but by failed flashing: the metal seal between the chimney and the roof deck. Copper chimney flashing is the most durable, reliable solution available.
What Is Chimney Flashing?
Chimney flashing is a system of metal pieces that create a watertight seal where the chimney penetrates the roof. A complete flashing system consists of: step flashing (individual pieces woven into the shingles or roofing along the chimney sides), counter flashing (embedded into the chimney mortar joints and overlapping the step flashing), and a saddle or cricket (a peaked copper structure behind wide chimneys that diverts water around the chimney).
Why Copper Outperforms Other Flashing Materials
Aluminum flashing lasts 15–20 years in New England's climate before corrosion and freeze-thaw fatigue cause failure. Galvanized steel is similar. Copper, by contrast, lasts 50–70 years — and can be soldered to create fully watertight seams that aluminum and steel cannot achieve. Copper also expands and contracts at a rate compatible with masonry, reducing stress at the flashing-to-chimney interface.
The Installation Process
Our copper chimney flashing installation follows a precise sequence: removing old flashing and cleaning the chimney base; cutting reglets (grooves) into the mortar joints for counter flashing; fabricating custom step flashing pieces on-site; installing step flashing woven into the roofing; installing and soldering counter flashing into the reglets; and fabricating and installing a copper saddle if the chimney is wider than 30 inches.
The entire process typically takes one to two days, and the result is a permanent, watertight seal that will outlast the chimney itself.
Beacon Hill Copper Roofing Co.
Boston's copper roofing specialists since 1987. MA Licensed & Insured.