How to Repair Leaking Chimney Roof Flashing

Roof flashing around chimneys can separate from the brick, allowing rainwater to leak inside the house. To repair loose roof chimney flashing:

1. 1. Clean any leaves or other debris out of the gap between the flashing and chimney.

1. 1. Use a chisel to remove any hardened roofing cement.

1. 1. Apply a generous amount of roofing cement behind the flashing.

1. 1. Use masonry nails or screws to reattach the flashing tight against the chimney.

1. 1. Cover any exposed nail or screw heads with roofing cement.

1. 1. Apply roofing cement to the joint between the flashing and brick.

1. Smooth the roofing cement out with a paint stirrer or putty knife.

Watch this video to find out more.

Further Information

• Leak-Proof Flashing: Fixing Leaks Around Chimneys (article)
• How to Clean and Inspect Your Roof (video)
• How to Replace a Damaged Asphalt Roof Shingle (video)
• How to Replace a Roof Vent Jack (video)

VIDEO TRANSCRIPT
The “L” shaped flashing that protects the joint between a roof and a chimney can sometimes pull away from the chimney, especially if it’s only held in place by roofing cement. Begin correcting the problem by removing any leaves or debris from the void, and then scraping or chiseling the dried roofing cement off of the bricks so the flashing will lay flat against them.

Now, apply a generous amount of new roofing cement to the bricks behind the flashing an inch or so below the top of the flashing. Use masonry screws or nails to hold the flashing tight against the bricks before you apply more roofing cement along the top edge of the flashing.

Finally, smooth out the cement with a putty knife, and apply cement to the heads of all the fasteners.