Chimney Cap Replacement in Los Angeles, CA

What a cap replacement actually involves

The job starts on the roof, not the driveway. The old cap comes off first, usually rusted screws, sometimes legs mortared into the crown. We measure the flue tile across its outside dimension. On the multiple-flue stacks common in period-revival houses, we measure the whole crown, corner to corner, plus tile heights, since clay tiles rarely sit at the same elevation. Then the crown gets inspected. New cap goes on last: clamped, lagged or screwed, and sealed where it meets masonry.

Prefabs are a different animal. The 1970s–2000s tract chimneys have a sheet-metal chase cover, not a crown. Galvanized covers rust through from the inside out. Near the coast and in the marine layer belt, that happens faster. Stainless with a cross-break and a drip edge is the fix. Water sitting flat on a cover is why the drywall below stains.

Caps in fire hazard zones double as spark arrestors. Canyon and foothill properties need woven or welded mesh meeting state spark arrestor sizing, not decorative screen with wide gaps.

We won't cap a chimney with an earthquake-cracked crown or separated masonry. The cap hides the problem and the water keeps coming. Crown first, cap second.