Chimney Flashing Repair.
You’ll want to install new chimney flashing if it’s missing, rusted through, falling out, or completely covered with roofing tar (a typical short-term fix that’s sure to be hiding bigger problems). It’s also a good time to install new flashing when you put on new shingles because you’ll want it to last as long as the new roofing (25 to 40 years).