Noticed water stains on the ceiling near your fireplace? Or worseâdrips during heavy rain or snowmelt? If your roof is leaking around the chimney, youâre not alone. Chimney leaks are one of the most common and most overlooked roofing issues homeowners in Alberta face. And if left untreated, they can lead to rot, mold, and expensive structural repairs.
Hereâs what causes chimney roof leaks, how to identify the problem, andâmost importantlyâhow to stop it.
đ Why Your Chimney Area Leaks
Chimneys are natural weak points in your roof system because they interrupt the uniform flow of shingles and require multiple materials to meet and seal together. Here are the top causes of chimney-related leaks:
1. Damaged or Missing Flashing
Flashing is the metal barrier that seals the space between your chimney and the roof. If itâs:
- Cracked
- Rusted
- Improperly installed
- Or missing altogether…
âŠwater will seep through gaps and enter your attic or ceiling.
2. Worn Counter Flashing
Counter flashing is embedded into the chimney brick or mortar and overlaps the step flashing below it. If this isnât watertight, water will run down the brick and behind your shingles.
3. Cracked Mortar or Bricks
Older chimneys can have deteriorating mortar joints or cracked bricks, which absorb and funnel moisture directly into the house.
4. Chimney Cap or Crown Issues
A missing or cracked chimney cap or concrete crown allows waterâand even snowâto enter from above.
đ ïž How to Stop the Leak Around Your Chimney
Step 1: Inspect the Flashing
Look for:
- Loose metal flashing or unsealed corners
- Signs of rust or corrosion
- Gaps between the chimney and roof surface
Fix: Replace any loose or damaged step flashing and reseal with roofing cement or install a full chimney flashing kit for long-term durability.
Step 2: Check the Mortar and Brickwork
Use binoculars or a close-up inspection to look for:
- Cracked mortar joints
- Loose bricks
- White staining (efflorescence) that signals water seepage
Fix: Repoint the chimney by grinding out and replacing deteriorated mortar. For major cracks, a chimney specialist may need to rebuild sections.
Step 3: Seal with a Waterproofing Agent
Apply a breathable masonry sealant to your chimney to prevent moisture absorption without trapping vapor inside.
Step 4: Install or Replace the Chimney Cap
A chimney cap acts like an umbrella, keeping water, snow, and debris from entering the flue. It also prevents birds and small animals from nesting.
Fix: If the cap is damaged or missing, install a stainless steel or aluminum model that fits your chimney top snugly.
Step 5: Inspect and Repair the Chimney Crown
The crown is the sloped concrete surface at the very top. Look for cracks or separation from the flue.
Fix: Small cracks can be sealed with crown repair cement. Major damage may require a full rebuild.
đ§ Should You DIY or Call a Pro?
If youâre comfortable on a roof and the damage is minor (like resealing flashing), DIY may be possible. But for issues involving:
- Structural damage
- Brick and mortar repair
- Persistent water intrusion
âŠit’s best to call a licensed roofer or chimney specialist in Alberta. Theyâll ensure all elementsâroofing, flashing, and masonryâwork together to seal the leak permanently.
đ§ A Note on Alberta Weather
Albertaâs freeze-thaw cycles can worsen chimney leaks. Water that enters small cracks will freeze and expand, widening gaps and worsening the leak over time. Thatâs why proactive chimney maintenance is especially important in our climate.
Final Thoughts
A roof leak around the chimney isnât just annoyingâitâs a warning sign. Water entering here can damage your insulation, drywall, framing, and even your foundation if left unchecked.
Take action early. With proper flashing, a sealed crown, and a reliable chimney cap, you can stop leaks for good and protect your home for years to come.