Why Does Water Enter Around Chimneys and Skylights?

Flashing is the thin metal or rubber material installed around chimneys and skylights to direct water away. Its job is to bridge the gap between the roof and the vertical structure. If this flashing becomes loose, corroded, or develops small holes, it loses its effectiveness. Water then easily flows underneath it, bypassing your roof's shingles and leading to interior leaks.

The installation quality of flashing is critical. Even new flashing can leak if it is not properly integrated with the roof underlayment and shingles. A common mistake is using the wrong type of flashing for your specific roof material. Overlapping sections incorrectly or using inadequate sealant can create vulnerable points from the very beginning.

Chimney flashing is complex because it must seal a masonry structure that expands and contracts at a different rate than the roof. It typically involves two layers: step flashing along the sides and counter flashing embedded into the chimney mortar. If the mortar joint holding the counter flashing deteriorates, water can run directly down the chimney into your attic or walls.

Another frequent problem is cracked crown or cap on top of the chimney. If this concrete seal is damaged, water enters the chimney chase itself. It can then travel down the interior brickwork and eventually seep out at the flashing level or cause moisture damage inside the fireplace and surrounding walls.

• Deteriorated mortar joints around counter flashing.
• Rusted, bent, or missing pieces of step flashing.
• A cracked or missing chimney crown or cap.
• Separation where the flashing meets the roof shingles.
• Improperly sized flashing that does not provide enough coverage.
• Accumulated debris, like leaves, that traps moisture against the flashing.

If you see water stains or dripping, contain the interior damage immediately. Place buckets and move furniture. Then, if it is safe, try to trace the water path in your attic to confirm the source is near the chimney or skylight. Avoid going on a wet roof yourself, as it is slippery and you could cause more damage or injure yourself.

Your next step is to contact local water damage pros for water extraction and drying. They have tools to remove water and moisture from walls and ceilings to prevent mold. For the permanent roof repair, you will need a qualified roofer to inspect and repair or replace the failed flashing and sealant. These are two separate trades for two different jobs.

• Contain interior water with buckets and towels.
• Safely inspect the attic to help locate the entry point.
• Contact local water damage pros for drying and moisture control.
• Hire a qualified roofer for a permanent flashing repair.
• Document the damage with photos for an insurance claim.
• Policies vary, and your insurer decides what is covered.