Chimney Leak at the Roofline

Where the Water Gets In

A chimney is a brick tower cut through the roof. Every place where it meets roofing is a seam, and every seam is a chance for rain to slip in. When a homeowner calls about a wet patch on the ceiling next to the fireplace, the water almost always entered at one of four spots:

• - The metal strips that seal the joint between the brick and the roof
• The concrete or mortar slab on top of the chimney
• The open top of an uncapped flue
• The brick and mortar of the chimney itself

Our dry seasons hide these problems for months. Then the first real storm of winter arrives in Pasadena and the stain shows up overnight.

The Metal at the Roofline

This is the most common source on our route. Roofers seal the brick-to-roof joint with two layers of metal. One layer is tucked under the shingles and bent up against the brick. A second layer is cut into the mortar joints and folded down over the first. Water hitting the brick runs down the outer piece, onto the roof, and away.

Problems start when:

• - The upper piece pulls out of the mortar joint as the mortar ages
• Someone sealed the joint with caulk instead of metal, and the caulk cracked
• A reroof left the old metal in place without refitting it
• The metal rusted through, often on the uphill side

The uphill side is worth a closer look. Water and leaves pile up there during a storm. Wide chimneys usually need a small peaked diverter, often called a cricket, built behind them to split the flow. Without one, a pool forms against the brick on every rain.

The Crown

The slab on top of the chimney is meant to shed water away from the flue and off the edges. Many older crowns were built from leftover mortar, which cracks after years of hot summers. Water runs through those cracks into the chimney and down the inside of the brick.

A crack you can see from the ground is usually wide enough to leak.

The Open Flue

A flue with no cap catches rain directly. In a heavy storm that can be a surprising amount of water. It soaks soot, rusts the damper, and sometimes shows up as a damp, sour smell in the room rather than a stain on the ceiling.

The Brick Itself

Old soft brick and worn mortar soak up water like a sponge. That moisture then moves inward. Leaks from the brick face are less common than the other three, but they do happen on older chimneys in neighborhoods like Highland Park and the older streets of Alhambra.

Why We Test Before We Quote

Guessing is expensive. Resealing the metal on a chimney that is leaking through its crown fixes nothing, and the stain comes back with the next storm. Before we price a repair, we run water at each suspect spot in turn, starting low and working up, while someone watches inside. The spot that wets the ceiling is the spot that gets fixed.

That test usually takes less than an hour and saves a lot of money.

What Repairs Look Like

Each fix is different, so each is quoted in writing after the test:

• - Loose or rusted roofline metal gets removed and new pieces fitted, with the upper layer set into fresh cuts in the mortar
• A cracked crown is sealed if the damage is light, or rebuilt with a proper overhang if it is not
• An open flue gets a stainless cap, which runs $160 to $630 installed
• Porous brick gets the bad joints repointed, then a breathable water repellent

When a cap alone solves the leak, that is what you pay for. You can send us the form with a photo of the stain and one of the chimney from outside, and we will tell you which of these looks most likely.

What You Can Do Now

Until the repair is done:

• - Put a bucket or towel under any drip and keep an eye on it
• Close the damper so wind-driven rain stays out of the room
• Take a photo of the stain each time it rains so we can see whether it grows

Do not climb onto a wet roof to look. The answer is not worth the fall.

Stains That Are Not the Chimney

Not every wet patch next to a fireplace comes from the chimney. On some houses the culprit is a roof valley close by, a plumbing vent, or condensation from an attic duct that sweats on cold mornings. A stain that appears without rain, or one that grows in summer, points away from the chimney. The water test sorts this out too, because if the chimney stays dry under the hose, we know to stop and tell you so rather than sell a repair it does not need.

Insurance and Paperwork

Some homeowners ask whether a chimney leak is covered by insurance. Policies differ, and we do not give coverage advice. What we can give you is a written report with photos of the source, the damage and the repair, which is usually what an adjuster asks for. Keep your own photos of the ceiling stain with dates as well.

Getting It Checked

A leak that started this winter rarely fixes itself. Call and tell us where the stain is and how long it has been there, and we will set up a test on the next dry day.