What is the correct way to install drip edge?

What the code actually requires

The International Residential Code, which Georgia adopts with state amendments, covers drip edge for shingle roofs in Section R905.2.8.5 of the 2018 and 2021 editions. The key numbers: drip edge is required at eaves and rake edges, adjacent pieces overlap at least 2 inches, the metal extends at least 1/4 inch below the roof sheathing and at least 2 inches back onto the deck, and it is fastened at no more than 12 inch spacing. Underlayment goes over the drip edge at the eaves and under it at the rakes unless the shingle manufacturer says otherwise.

Getting the sequence right

1. Fasten eave drip edge directly to the deck, with its lower leg kicked out over the fascia or into the gutter.
2. Roll leak barrier or underlayment over that eave flange.
3. Run underlayment up the rakes, then install rake drip edge on top of it.
4. At each corner, let the rake piece lap over the eave piece so water coming down the rake lands on the eave metal, not behind it.
5. Lap joints in the direction water travels, upper pieces over lower ones.

Mistakes worth catching

• Nails placed near the outer edge where shingles will not cover them.
• Eave drip edge tucked behind the gutter so water runs down the fascia board.
• Open gaps at outside corners, which is where fascia rot usually begins.
• Bent, reused metal from the old roof.

The profile matters too: an L-shaped edge, a T-shaped edge with a kick, and a gutter apron each suit different fascia and gutter setups. More background in drip edge explained and gutter sizing and guards.