💧 How to Install Roof Drip Edge Flashing (Step-by-Step DIY Roofing Tutorial)

Q: Should drip edge go under or over underlayment?

At eaves, install drip edge under underlayment; at rakes, install it over underlayment.

Q: How much should drip edge overlap?

Overlap each drip edge section by at least 2 inches to prevent leaks.

Q: Do all roofs need drip edge?

Yes — building codes in most regions require drip edge to protect fascia and prevent water infiltration.

Installing aluminum roof drip edge flashing along eave and rake edges — Properly installed drip edge flashing directs water into gutters and prevents rot along fascia and roof decking.

Roof drip edge flashing is a critical waterproofing detail that protects your home’s fascia and roof edges from water damage. Installed along eaves and rake edges, drip edge ensures rainwater flows into gutters — not behind them. This guide covers every step of a professional-grade installation with clear diagrams and best practices.

🧰 Tools & Materials Needed

Gather the right tools and materials before beginning to ensure a clean, efficient installation:

🔩 Drip edge flashing – aluminum or galvanized steel in 10-ft sections
🔨 Roofing nails – 1¼″ galvanized with wide heads
📏 Chalk line & snips – to mark and cut drip edge pieces cleanly
🧴 Roofing sealant – to seal seams and overlaps
🧤 Work gloves & safety glasses – protect hands from sharp metal edges
🪜 Extension ladder – stable access to eaves and rakes

🔧 Recommended Roofing Tools & Supplies

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📋 Step-by-Step Drip Edge Installation

1. Measure and cut drip edge.
Use tin snips to cut 10-ft sections to match the roof’s length, leaving a ½″ gap between pieces for expansion.
2. Start at the eaves (bottom edge).
Position the drip edge with the lower flange extending over the fascia and the upper leg on top of the roof decking.
3. Nail every 8–10 inches.
Fasten along the top flange using roofing nails 1 inch above the edge, ensuring pieces lay flat and flush.
4. Overlap sections by 2 inches.
Each new section should overlap the previous by at least 2 inches to prevent water infiltration at seams.
5. Apply sealant at joints.
Use roofing sealant under overlaps and around corners for watertight protection.
6. Install rake edge flashing.
At gable ends, install rake edge flashing over the underlayment for wind resistance and clean finish.
7. Integrate with gutters.
Ensure the drip edge’s lower flange sits inside the gutter for proper drainage alignment.

✅ Best Practices for Drip Edge Installation:
• Always install drip edge beneath underlayment at eaves, but above it at rakes.
• Maintain consistent nail spacing to prevent flutter in wind.
• Avoid bending or creasing metal — it can cause water traps.
• Paint cut edges with rust-preventive coating if using steel.
• Verify local building code requirements for overlap and fastener spacing.

💡 Pro Tips for a Perfect Finish

Use factory-painted drip edge for longer-lasting curb appeal.
Seal corners and joints with polyurethane roofing caulk.
Trim gutters if necessary to allow flange clearance.
Install before shingles to achieve proper underlap protection.
Check alignment with fascia every few feet to maintain a straight line.

❓ FAQ – Drip Edge Flashing Questions

Q: Should drip edge go under or over underlayment?
At eaves, drip edge goes under underlayment; at rakes, it goes over underlayment.

Q: How much should drip edge overlap?
Each piece should overlap the previous one by at least 2 inches.

Q: What gauge metal is best for drip edge?
Aluminum (0.019–0.024") or galvanized steel (26–28 gauge) provides ideal strength and corrosion resistance.

Q: Can I install drip edge without removing gutters?
Yes — slide the lower flange behind the gutter’s back edge carefully without bending.

Q: Do all roofs need drip edge?
Yes — most building codes require it to prevent fascia rot and water intrusion.

⚠️ Safety Reminder

Wear gloves when handling flashing to avoid sharp-edge cuts. Use stable ladders and never install metal flashing in wet or windy conditions.