Chimney Flashing Repair in Pasadena: Written Report, Licensed Technicians

A century-old brick chimney in Pasadena moves in ways a 1990s inland stucco home never will. Craftsman bungalows around Sierra Madre and the older brick stacks in Temple City were built with soft lime mortar and clay masonry that expands, settles, and shifts a little every season. That movement works the flashing loose at the joint where the chimney meets the roof. Add a few decades of small earthquakes flexing the structure, and the original galvanized flashing pulls away from mortar joints that were tuck-pointed generations ago. You end up with a gap that a newer tract home simply doesn't develop the same way.

Rosemead sits close enough to share the same building era, and we see the same pattern there: counter flashing that was mortared straight into a joint, then cracked as the brick moved. On a period home the fix isn't just re-caulking. Step flashing has to interleave with each course of roofing, and counter flashing needs to tuck back into a freshly cut reglet in sound masonry, not smeared over crumbling mortar. When the mortar itself is failing, the flashing repair and the masonry work go together. That's why leak diagnosis on these homes starts at the chimney, not the roof surface.

Time your flashing work for early fall, before the first real storms roll through the San Gabriel Valley. Our rain arrives in short, heavy bursts, so a marginal flashing joint that survived a dry year will fail the first time three inches fall in a weekend. If your chimney sits on the uphill side of a sloped roof, ask about a cricket, the small peaked diverter that splits water around the back of the stack instead of letting it pool against the mortar. On a wide period chimney, skipping the cricket is the most common reason a fresh flashing job still leaks the following winter.

Choose your metal deliberately. Lead flashing shapes tightly against irregular historic brick and lasts decades, which is why it suits Sierra Madre's older stacks; aluminum is cheaper but dents and works loose faster on a moving chimney. Before you assume the flashing is the culprit, rule out the crown and the mortar joints, since all three cause the same ceiling stain. The NRCA roofing and flashing best practices are a solid reference for how these details should be layered. If the diagnosis points past the flashing into the brick itself, our chimney repair work covers the full structure.