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Home / Code Guides / Drip Edge

Drip Edge Requirements — Where It Goes & How It Laps

Drip edge stopped being optional in the IRC years ago — asphalt shingle roofs must have it at both eaves and rakes. The trick most installers get wrong is the layering: underlayment goes over the drip edge at the eaves but under it at the rakes, so water always drains onto metal, never behind it.

RequirementModel Code StandardSection
Where requiredA drip edge is required at eaves and rake edges (gables) on all asphalt shingle roofsIRC R905.2.8.5
LapsAdjacent pieces of drip edge must overlap each other by at least 2 inchesIRC R905.2.8.5
ProfileThe drip edge must extend at least 1/4 inch below the roof sheathing and extend back up onto the roof deck at least 2 inchesIRC R905.2.8.5
Layering at eavesAlong the eaves, the underlayment is installed over the drip edge — water running down the underlayment sheds onto the metal and off the roofIRC R905.2.8.5
Layering at rakesAlong the rakes, the drip edge is installed over the underlayment — wind-driven water at the gable edge stays on top of the feltIRC R905.2.8.5
FasteningDrip edge must be mechanically fastened to the roof deck at no more than 12 inches on centerIRC R905.2.8.5

Worth knowing

  • An easy way to remember the layering: think about where the water is. At the eave it is on the underlayment heading down, so metal goes under. At the rake it is being blown sideways across the surface, so metal goes over.
  • In ice barrier territory, the ice and water shield at the eave laps over the drip edge the same way underlayment does — set the metal first, then membrane onto it.
  • Gutter apron and drip edge are different profiles. At an eave with gutters, a gutter-apron style that directs water into the gutter beats a standard D-profile hanging behind it.
  • Re-roofs count: tearing off to the deck triggers current code, so a 1990s roof that never had drip edge gets it on the new roof.
Sections cite the 2021 International Residential Code and 2023 National Electrical Code as model standards. This is BuildSpec’s own summary — not ICC or NFPA text; read the authoritative language at codes.iccsafe.org. Your state may be on a different edition with amendments — check your jurisdiction page or get an Address Report.
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