What light use and a dry climate do to an LA chimney
A chimney in Los Angeles lives a strange life. It works hard for a handful of evenings and then goes dormant for the better part of the year, and that long idle stretch is where a lot of the trouble starts. With no regular fire to keep it dry and active, the flue becomes an inviting cavity. Birds nest in it during the spring, squirrels and the occasional raccoon find their way in, and the debris they leave behind blocks the draft and feeds the next chimney fire. The first cold night of the season is often when a homeowner discovers all of this the hard way, with smoke pushing back into the living room instead of rising up the stack.
The dry climate adds its own twist. Wood-burning fireplaces that are only lit occasionally tend to burn cool and smoky, especially when the wood is not fully seasoned, and a cool, smoky fire is exactly the kind that lays down creosote fastest. So the home that burns the least can actually carry the more dangerous flue, because the little burning it does is the wrong kind and it never gets the heat that would help keep the liner clean. On top of that, the long dry season raises the stakes on the whole stack, since a stray ember from an uncapped or poorly drafting chimney is the last thing any Los Angeles neighborhood wants drifting onto a dry roof or hillside. A chimney here is not low-maintenance just because it is low-use, and reading it correctly is the whole point of an inspection.