Do it in October, from the living room and the sidewalk. More than 90 percent of Los Angeles rain falls between November and April. So a South Bay chimney has spent six dry months opening up small cracks, and the first real storm tests all of them on the same night. Twenty minutes with a flashlight and a pair of binoculars will tell you whether that storm is going to be a problem.
Why the first storm finds every crack at once
Masonry moves. Brick and mortar swell a little in the afternoon heat and shrink back overnight. A whole summer of that opens hairline cracks in the crown and along the joints.
In August those cracks are harmless because nothing is falling on them. Then a wet week arrives. Every opening takes water at once, and brick is porous, so it keeps drinking for as long as the rain lasts.
A small fault found now is usually a small job. The same fault left through a wet winter tends to show up in March as a stained ceiling and a damper rusted open.
Start inside, at the fireplace
Open the damper and shine a light up. Then look down.
- Rust flakes on the firebox floor or on the smoke shelf behind the damper. Water has been reaching the metal
- A damper that sticks or will not close all the way
- White, chalky bloom on the firebox brick or the chimney breast
- A musty, sooty smell that was worse after last winter’s rain
That white bloom is efflorescence. Water moving through masonry dissolves salts inside the brick and leaves them on the surface when it dries. It wipes off, but it tells you water is travelling through the wall.
Now check the ceiling and the walls either side of the chimney. If there is an old stain, trace around it lightly in pencil today. After the first storm you will know in ten seconds whether it grew.
Then walk out to the sidewalk
Binoculars do most of the work from the street. Stand far enough back that you can see the top of the chimney and where it meets the roof.
Look at the cap first. It should be there, sitting square, with the mesh intact on every side. The crown is the slab of mortar or concrete under it. Look for cracks across it, or corners that have broken off. At the roofline, the metal flashing should lie flat against the brick. Lifted edges and old sealant peeling back are where water runs in.
Last, the brick face. Flaking or pitted faces mean the brick is already taking on water, and missing mortar between courses is an open door for the next storm.
What each sign usually points to
| What you see | Where the water is usually getting in |
|---|---|
| Rust flakes in the firebox | Straight down the flue, past a missing or rusted cap |
| Crack across the crown | Into the masonry around the flue, then down inside the chimney |
| Stain on the ceiling beside the chimney | Flashing at the roofline, sometimes the crown. The stain can sit a room away from the entry point |
| White bloom on the brick | Through the brick face or the mortar joints |
| Flaking brick faces | The brick itself. This is spalling, and it gets faster once it starts |
Stay off the roof for all of this. Clay tile cracks under a boot, and a composition roof with a season of dust on it is slick.
Why beach city chimneys need the check more
Salt. Near the water in Redondo Beach, Hermosa Beach, Manhattan Beach and El Segundo, sea spray settles on the brick all year. Rain carries it into the pores. When the brick dries, the salt crystallises inside it. The crystals push outward. That is one of the ways a brick face starts to flake.
The Palos Verdes peninsula adds wind. A chimney standing on an exposed ridge takes rain sideways off the ocean, straight into the flashing and the face of the brick. Marina del Rey and Westchester sit close enough to the water to get the salt as well.
Inland, in Lakewood or Norwalk, the storms are the same storms without the salt. The check is still worth doing there, and the list above is the same.
What to fix before the rain, and what can wait
Fix anything that lets water straight in. A missing cap, a crown cracked right through, flashing that has lifted away from the brick. Those three take the most water in the least time.
Staining on its own can wait, and so can a cap that looks tired but still has good mesh. If you want the masonry sealed, do it now. A breathable sealer has to go onto dry brick. That makes waterproofing a dry weather job, and October is the tail end of the window.
Found something and not sure what it means? Inspections start at $69, and you get photos of what we find before anyone quotes a repair. We are open every day, 8am to 8pm. Call 818-348-1993.
Questions South Bay homeowners ask before the rainy season
When does the rainy season start in Los Angeles?
The wet season runs from November through April, and most of the rain lands between December and March. October storms are less common, but they do happen, so early in the month is the time to look.
My chimney has never leaked. Do I still need to look?
Yes. Crowns and flashing wear gradually, and the first sign is often the stain. Catching a cracked crown in October costs less than catching it through the ceiling in February.
Can a chimney for a gas fireplace leak?
It can. The crown, the cap, the flashing and the brick are the same whatever burns below them. Rain treats a gas chimney exactly like a wood burning one.
Is a leak the chimney or the roof?
If the stain sits beside the chimney breast, or water shows up in the firebox, start with the chimney. Water travels along rafters before it shows, though, so the only sure answer comes from looking at the top.
If the check turned something up, chimney leak repair explains how we trace water back to where it gets in. For brick that is already soaking up rain, read about chimney waterproofing. If the cap was the problem, our guide to why caps rust out faster in the South Bay covers which metals hold up. Or book a chimney inspection and we will check it for you. We have worked chimneys from Redondo Beach to the harbor since 1977.