The short answer
Check the Flashing First
Flashing is the metal or rubber strip that seals the gap between the chimney and the roof. If it is cracked, rusted, or lifted, water can slip behind it and run down into your home. Look for gaps, missing sealant, or sections that pull away from the chimney.
Flashing failure is the most common cause of a chimney leak. The metal can expand and contract with temperature changes, and over time it may loosen. If you see daylight through any gap, that is an obvious sign water can get in. A local water damage pro can re-seal or replace the flashing to stop the leak.
Inspect the Chimney Masonry
Cracks in the brick, mortar, or concrete can let water soak into the chimney and then drip down inside your wall. Rain that hits the chimney can also splash onto the roof and find a small opening. Examine the chimney from the roof if it is safe to do so, and also look from inside your attic near the base.
Mortar joints are especially vulnerable because they erode over time. If you see crumbling mortar or hairline cracks, water can travel through them. Repointing the mortar or sealing the brick can help, but the pros may need to address the flashing at the same time. Water damage inside the wall can spread quickly, so act fast.
Look for a Second Roof Layer
Some homes have a second roof layer, like a newer shingle over an old one. That extra layer can change how water flows around the chimney. If the top layer is not cut properly around the chimney, water can pool and work its way under the flashing.
You might also have a cricket, which is a small ridge that diverts water away from the chimney. If the cricket is missing or poorly built, water can sit against the chimney and increase the chance of a leak. A roofer can assess the roof slope and recommend a cricket if needed.
- Look for gaps in the flashing
- Check for cracked mortar
- See if a cricket is present
- Look for lifted shingles near the chimney
- Inspect the counterflashing where it meets the brick
Trace the Water Path
Sometimes the leak appears near the chimney, but the water enters somewhere else. Water can run along a rafter or a pipe before it drips down. In your attic, look for water stains, dark streaks, or damp insulation that can help you trace the path back to the entry point.
If you cannot find the source, leak detection can help. The pros use moisture meters and other tools to locate hidden moisture without tearing open your roof. This can save time and avoid unnecessary repairs. It is a good step before you commit to a full roof replacement.
When to Call the Pros
If you see active dripping, sagging drywall, or mold, you need professional help soon. Water damage can weaken wood and lead to bigger structural issues. A local water damage pro can extract standing water, dry the area, and repair the drywall after the roof leak is fixed.
The cost of a repair depends on the extent of the damage, the type of roofing material, and the accessibility of the chimney. It often ranges from a few hundred to a few thousand dollars, but the exact price depends on those factors. Getting the leak fixed early can prevent more expensive repairs later.
- Active dripping or water stains
- Sagging drywall or bubbling paint
- Mold or musty smell
- Visible daylight through roof gaps
- Damaged flashing or cracked mortar
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Call (425) 407-5186 any time, day or night, and describe what happened.
Call Now (425) 407-5186Frequently asked questions
Can I fix a chimney flashing leak myself?
You can try sealing small gaps with roofing cement or caulk, but a proper flashing repair often requires removing old metal and installing new pieces. If you are not comfortable on a roof, call a roofer. A temporary patch might hold for a while, but a permanent fix is safer.
How do I know if the leak is from the chimney or the roof?
Check the flashing and the chimney base for obvious damage. Also inspect the roof shingles around the chimney for cracks or missing pieces. If you cannot find the entry point, a water damage inspection can help trace the moisture path and pinpoint the source.
What should I do if the leak is already causing water damage?
Move furniture away and place a bucket to catch drips. Dry the area as much as you can to prevent mold. Then contact a water damage pro to extract standing water and dry the structure. If you have insurance, check your policy to see what is covered. Policies vary, and your insurer decides what is covered.