First rain of the season: why chimneys leak in Southern California, and what to check this week

Why the first rain finds the problems

From May to October most of Southern California gets almost no rain. All summer the top of the chimney sits in strong sun and heat. Santa Ana winds blow through in the fall. The concrete crown on top can crack, sealant around the flashing dries out, and a cap can work itself loose. Nothing shows while it is dry. Then the first real storm comes, and water finds every one of those gaps at once.

That's why we get the most leak calls in the first week of rain, not in the middle of winter.

Signs it is coming from the chimney

Water or wet ash in the firebox, or drips you can hear inside the fireplace.

A brown stain on the ceiling or wall right next to the chimney that grows after each rain.

A damp, musty smell around the fireplace a day or two after the storm.

Rust on the damper, or a damper that suddenly sticks.

On a factory-built (metal) fireplace with a wood or stucco chase: stains near the top of the chase, or water running down inside.

Write down when you see it: during the rain, right after, or only when the wind blows. That one detail helps a technician narrow down the cause. There is more on this in our guide What to record when your chimney leaks.

What you can check yourself, safely

From the ground, look at the top of the chimney. Is the cap there and sitting straight? A cap that is missing or tilted after the fall winds is the most common cause we see.

Inside, use a flashlight on the firebox and the damper. Fresh water marks or rust are worth a photo.

Put a tray or towel in the firebox to protect the floor until it is checked.

Do not go up on a wet roof. Not to look and not to patch. It isn't worth the risk.

Don't light a fire if water has been coming into the firebox until someone has looked inside the flue.

What usually lets the water in

The cap: missing, loose, or the wrong size for the flue. Without a cap, rain falls straight down the chimney. More about the different parts is in Chimney cap, crown, or chase cover?.

The crown: the concrete slab on top of a masonry chimney. Hairline cracks from heat let water into the bricks.

The flashing: the metal seal where the chimney meets the roof. When it lifts or the sealant dries out, water runs into the wall or ceiling, often away from the fireplace itself.

Brick and mortar: old mortar joints soak up water like a sponge.

The chase cover: on metal fireplaces, a rusted top pan lets water straight into the chase.

A leak often has more than one cause. Fixing the cap won't help if the flashing is the problem, which is why we look at the whole top and the roof line together.

When to call, and what the inspection covers

When to call: if water is getting into the firebox, the stain keeps growing, or you can see from the ground that the cap is loose or missing, it's worth booking before the next storm.

What we check: a technician checks the cap, crown, flashing and masonry from outside, and the firebox, damper and flue from inside. You get photos the same day, and the price in writing before any work.

New-customer offers: the inspection and leak check is free for new customers. If the cap needs replacing, new customers get $99 off a chimney cap.

Phone: in Santa Barbara and Ventura County call (805) 586-9535. In Orange County call (949) 602-7844. We book Sunday to Friday.