Chimney Leak Repair After Monsoon Storms

Sky Harbor averages about 7.22 inches of rain a year by NWS 1991–2020 normals, and a lot of it arrives in short, wind-driven bursts. The NWS dates the monsoon June 15 to September 30. Rain that hits a chimney sideways finds openings ordinary rain never reaches: under a cap skirt, behind a chase-cover edge, beneath the tiles beside the chimney. The leak happens in August and often isn't found until October or November, when the fireplace is opened again and there is rust in the firebox or a stain on the ceiling.

Tracing the water is the real job, because where it shows is rarely where it gets in. Water that enters at a cover runs down inside a framed chase and appears at the firebox. Water that enters at the roof line travels along the underlayment and shows up as a ceiling stain several feet away.

Signs you need this

• Rust or water marks in the firebox after the summer
• A ceiling or wall stain near the chimney
• Musty smell from the fireplace once the weather cools
• Stains on the stucco, or white deposits on brick below the top
• Cracked or slipped roof tiles around the chimney

How we do it

1. Ask when it leaksWind direction and storm type tell us which side, and which part, to start with.
2. Work top downCap, crown or chase cover, flue collar, then the roof line and flashing, with photos of each.
3. Test if neededWhen the source isn't obvious, we wet one area at a time, from the bottom up, until we find the one that leaks.
4. Repair and recheckThe entry point is fixed first; sealing or coating follows only if the masonry needs it.

Where Valley chimneys take on water

On a framed stucco chase, the cover and the collar around the flue are the usual entry. On a brick chimney it is the crown, the mortar joints and the brick itself, which soaks up water if it has never been treated. On either kind, the flashing where the chimney meets the roof is the other big source.

Fixr's figures: repairing a water leak in a fireplace or chimney runs $200 to $1,500, flashing repair $200 to $300, and water repellent on a masonry chimney $150 to $400.

• Chase cover and storm collar
• Crown cracks on brick
• Flashing at the roof line
• Porous brick and mortar
• Cap missing or damaged

Tile roofs and chimney flashing

Concrete and clay tile roofs are the norm on a lot of Valley homes, and they work differently from shingles. The tiles shed most water, but the underlayment beneath them does the real waterproofing. At a chimney, the flashing has to tie into that underlayment and be shaped to the tile profile. When either part fails, water runs under the tiles and comes out inside.

Upslope of a wide chimney, water can pile up against the back. A cricket, or saddle, steers it around the sides; chimneys built without one are a common leak point.

Why fix it before you light the fireplace

Water left in a factory-built firebox rusts the metal and can damage refractory panels. In a framed chase it soaks framing and stucco, and on a masonry chimney it breaks down mortar. A leak is cheaper to fix in October than after a second monsoon season.

The leak evaluation is free, and your price is written down before any work starts.