Drip Edge

Drip edge is a strip of formed metal, usually aluminum or galvanized steel and sometimes copper, installed around the roof's perimeter. One flange lies flat on the roof deck under the roofing. The other hangs down past the deck edge so water drips clear of the fascia. Vinyl versions exist but are less common.

• Directs runoff into the gutter instead of behind it.
• Protects the deck edge and fascia from water wicking back and causing rot.
• Supports the edge of the shingles so they don't sag over the edge.
• Closes the gap between the deck and fascia against wind-driven rain and pests.

Drip edge runs along the eaves (the lower, horizontal edges) and the rakes (the sloped edges at a gable end). The layering is different at each. At the eaves it usually goes under the underlayment, so water on the underlayment drains onto the metal. Along the rakes it usually goes over the underlayment. Manufacturer instructions can differ, especially where an ice barrier is used at the eaves.

• Missing drip edge: water stains, peeling paint and rot on the fascia and deck edge; water running behind the gutter.
• Wrong layering: underlayment placed under the drip edge at the eaves can send water behind the metal.
• Unlapped joints: gaps between sections let water through.
• A gap above the gutter: water misses the gutter and runs down the fascia.
• Corrosion: including galvanic corrosion where dissimilar metals touch, such as aluminum drip edge against copper or steel.
• Bent sections: usually from ladders or ice.