Drip edge is the L-shaped metal flashing installed along the eaves and rake (sloped sides) of your roof. It directs water off the roof and into the gutter, keeping it from running back onto the fascia or under the shingles.
Why most modern building codes require it
Without drip edge, water wicks behind the gutter and rots the fascia. Most jurisdictions added drip edge to the building code over the past 15 years.
On a storm-damage claim
If your roof predates the drip-edge requirement, code-required upgrades when the roof is replaced are typically a covered cost — but only if the line item is included on the Statement of Loss. This is one of the most commonly missed line items and a frequent supplement target.