Chimney Flashing and Leak Repair

Flashing is the layered metal that seals the joint where the chimney passes through the roof. It's one of the most common sources of chimney leaks, because it has to stay watertight through years of sun, expansion, roof movement, and the heavy, wind-driven rain Tamarac gets. When it lifts, corrodes, or was never sealed well, water runs down the side of the stack and into the roof deck, the attic, and the ceiling below.

Telltale signs of a flashing problem are water stains on the ceiling near the chimney, damp framing in the attic after a storm, rust or lifted metal visible at the roof line, or a leak that only shows up during heavy rain. Not every chimney leak is flashing, though — many start at a cracked crown or cap, so flashing repair and chimney crown and cap replacement are often considered together.

Tamarac's weather is unusually hard on flashing. Salt-laden coastal air corrodes metal, intense sun bakes sealant until it cracks, and the region's heavy downpours test every seam at once. A flashing detail that might last decades in a milder, drier climate can fail years sooner here, which is why water near the chimney after a storm should be looked at promptly rather than waited out.

Because flashing sits at the junction of masonry and roof, a lasting repair sometimes means addressing the mortar joint the counterflashing sets into as well. If those joints are worn, pairing the flashing work with tuckpointing and brick repointing gives the new flashing a sound joint to key into.