Roofer how-to
How to Flash Around a Chimney
Chimneys are one of the most common sources of roof leaks.
Quick answer
Chimneys are one of the most common sources of roof leaks. In short: install; install; weave, then complete the remaining steps below.
Step by step
Install ice and water shield up the chimney sides and around its base.
Install apron flashing along the low side of the chimney.
Weave step flashing with each shingle course up the sides.
Install a cricket or saddle on the high side of wide chimneys to divert water.
Cut a reglet into the mortar and install counterflashing over the step flashing.
Seal the counterflashing joint with a compatible sealant.
Safety reminders for roofers
- Use fall protection whenever you work on a roof or near an edge
- Keep ladders secured, extended three feet above the landing and set at the right angle
- Stay hydrated and take breaks in hot weather
- Watch for overhead power lines when moving ladders and materials
Key terms
Square · Pitch · Underlayment · Ice and water shield · Drip edge · Flashing: see the full roofer glossary.