Drip Edge Installation per IRC

Why this matters

A roof without drip edge fails inspection in every jurisdiction since the 2012 IRC update (R905.2.8.5). A roof with drip edge installed in the wrong sequence (under underlayment at eaves, over at rakes) also fails inspection because the water-flow detail is wrong. The detail is simple and the parts are cheap (a modest per square for the metal); the failure mode is universally in the installation sequence and lap. A roofer who can install drip edge correctly on the first pass closes inspections faster, has fewer leak callbacks at the rake-corner interface, and avoids the redo that wipes out the project margin.

When to use

Drip edge is required on every new roof and every reroof per IRC R905.2.8.5 (asphalt shingles), R905.4.6 (metal shingles), and parallel sections for other coverings. The requirement covers:

• Eaves (the horizontal edge at the lower roof line)
• Rakes (the inclined edge at the gable ends)
• Around dormers (where the roof meets the dormer wall)
• At any roof termination edge

Reroof: drip edge is replaced as part of the tear-off; old drip edge stays only if it is sound and the manufacturer's warranty does not require replacement (most warranties do require new drip edge).

Tools and materials

• Drip edge: typically 0.019 inch or 0.024 inch aluminum, 8 to 10 ft lengths
• Brand options: Berger Building Products, M-D Building Products, Quality Edge, Atlas, regional fabricators
• Galvanized roofing nails (8d common) or stainless if coastal
• Tin snips
• Hammer or pneumatic nailer
• Chalk line
• Measuring tape
• Underlayment (felt or synthetic, already discussed)
• Ice and water shield (for eave installations in cold climates)
• Caulk (silicone or roofing sealant) for splice joints
• Crayon for marking

Safety

Roof work over 6 ft above grade requires fall protection per OSHA 1926.501. Specific to drip edge install: working at the edge of the roof, often before guardrails or anchor points are in place, is high-risk for falls.

The water-flow rule

Drip edge directs water from the underlayment outward, away from the fascia and into the gutter (or off the edge directly). The detail must respect water-flow direction:

• At eaves: drip edge is installed BEFORE underlayment. The underlayment then laps OVER the drip edge. Water on the underlayment flows down, over the drip edge, off the roof.
• At rakes: drip edge is installed AFTER underlayment. The drip edge laps OVER the underlayment. This prevents wind-driven rain on the rake side from being driven under the drip edge into the underlayment lap.

This is the most-failed detail. Installing drip edge over underlayment at eaves means water from the underlayment can leak BEHIND the drip edge into the fascia. Installing drip edge under underlayment at rakes means wind-driven rain at the rake can bypass the underlayment and reach the deck.

Procedure

Step 1: Verify the existing fascia and deck

Drip edge attaches to both the deck (with nails) and may rest against the fascia. Verify:

• Deck is solid at the eave
• Fascia is straight, plumb, and not rotted
• Any soffit board issues are addressed before drip edge install

A rotted fascia under drip edge is hidden until the next tear-off; replace any compromised fascia before drip edge installation.

Step 2: Install drip edge at eaves

1. Snap a chalk line if needed to keep the drip edge straight
2. Position the first piece flush with the fascia (the vertical leg of the drip edge sits against the fascia)
3. Nail through the horizontal leg into the deck, every 8 to 12 inches typically
4. Lap subsequent pieces 2 to 3 inches over the previous
5. Where pieces lap, optional: a bead of sealant in the lap, especially in coastal or high-wind areas
6. Continue along the entire eave

The drip edge should extend 1/4 to 1/2 inch past the fascia / gutter board for proper drip behavior.

Step 3: Install ice and water shield at eaves (cold-climate regions)

In areas requiring ice and water shield per R905.1.2:

1. Install ice and water shield over the drip edge at the eave
2. Extend the shield up the roof at least 24 inches past the building wall line (verify against local jurisdiction)
3. Self-adhered backing sticks to the deck and to the drip edge

The ice and water shield is the eave-side water barrier; the drip edge is the metal trim. They work together: shield seals the deck, drip edge directs water off.

Step 4: Install underlayment over eave drip edge

1. Roll underlayment from eave upward (lower courses first)
2. The lowest course laps over the eave drip edge (water flow direction)
3. Fasten per underlayment requirements

Step 5: Install drip edge at rakes (after underlayment)

1. Roll the underlayment up to and over the rake edge (extend it past the rake)
2. Trim the underlayment at the rake
3. Install drip edge over the underlayment at the rake
4. Nail through the horizontal leg into the deck every 8 to 12 inches
5. The rake drip edge laps OVER the eave drip edge at the corner (water flows from rake to eave)

Step 6: Lap drip edge at corners

At the corner where eave drip edge meets rake drip edge:

• Eave drip edge runs continuous along the eave (do not stop at corner)
• Rake drip edge starts at the corner and runs up the rake
• Rake drip edge laps OVER the eave drip edge at the corner

A cut detail is required for the corner: the rake drip edge is bent or cut to form a clean miter that sheds water onto the eave drip edge.

Step 7: Lap drip edge at gable peak

Where two rake drip edges meet at the gable peak:

• Trim the upper end of each rake drip edge to form a clean joint
• Apply roofing sealant or use a manufacturer's peak detail
• Alternatively, cap with a separate peak flashing

Step 8: Install shingles over drip edge

The first course of shingles (the starter course) is installed flush with the drip edge edge or slightly recessed per the shingle manufacturer's instructions. The starter course's tar strip bonds the first course to the underlayment and to the drip edge.

Acceptance criteria

References

• IRC 2021, Section R905.2.8.5 (Drip edge for asphalt shingles).
• IRC 2021, Section R905.4.6 (Drip edge for metal shingles).
• IBC 2021, Section 1507 (Roof coverings).
• ASTM A653 (Steel sheet for drip edge).
• NRCA Roofing Manual: Steep-Slope Roof Systems, current edition.
• ARMA (Asphalt Roofing Manufacturers Association) technical bulletins.
• Manufacturer instructions: Berger, M-D, Quality Edge.
• Manuall internal: Roofing Repair Flashing, Roofing Asphalt Shingle Replacement, Roofing Gutter Integration Reroof.