What Is a Drip Edge and Does Your Roof Need One?
A drip edge is an L-shaped metal flashing installed along the eaves and rakes (sides) of a roof. It directs water away from the fascia board and into the gutter, preventing water from wicking back under the shingles and rotting the roof edge. Drip edge is required by the International Residential Code (IRC) on all asphalt shingle roofs. It costs $1–$3 per linear foot for materials and is installed beneath the underlayment at the eaves and over the underlayment at the rakes.
Cost Breakdown
| Service | Low | High | Notes |
|---|---|---|---|
| Drip edge (galvanized steel, materials only) | $1 | $2 | Per linear foot |
| Drip edge (aluminum, materials only) | $1.50 | $3 | Per linear foot; won't rust |
| Full home drip edge installation (during re-roof) | $200 | $600 | 150–250 linear feet typical |
| Drip edge retrofit (without re-roofing) | $400 | $1,000 | Requires lifting shingle edges |
What a Drip Edge Does
Without a drip edge, water running off the roof's last shingle follows surface tension back along the underside of the shingle and onto the fascia board. Over time, this constant moisture rots the fascia, soffit, and eave decking. A drip edge breaks this surface tension by extending the roof edge out 1–2 inches beyond the fascia, directing water down and into the gutter.
Drip edge also prevents wind-driven rain from getting under shingles at the roof edge, keeps insects and small animals from entering the gap between the deck and fascia, and gives the roof edge a clean, finished appearance.
Types of Drip Edge
- Type C (L-style): A simple L-shaped bend. The most basic and least effective design. Adequate for low-slope roofs with gutters.
- Type D (T-style or D-metal): Has an additional kick-out flange that directs water further from the fascia. The standard choice for residential roofing. Handles higher water volume and provides better protection.
- Type F (gutter apron): Extended lower leg designed to reach into the gutter. Used when the gutter is positioned far from the fascia or when maximum water capture is needed.
Materials include galvanized steel (most common, $1–$2/ft), aluminum ($1.50–$3/ft), and copper ($5–$15/ft for premium aesthetics).
Installation Details
Proper drip edge installation follows a specific layering order:
- At the eaves: Drip edge goes directly on the deck, under the underlayment. This ensures water that gets under the shingles runs over the drip edge, not behind it.
- At the rakes: Drip edge goes over the underlayment. This prevents wind-driven rain from entering at the roof edges.
The metal is face-nailed every 12 inches along the top flange. Joints should overlap by 2–3 inches with the upper piece overlapping the lower to shed water. At corners, the drip edge is either mitered or lapped with one piece extending past the other.
Is Drip Edge Required by Code?
Yes. The IRC Section R905.2.8.5 requires drip edge on all asphalt shingle roofs. Some older homes were built without it, and some roofing contractors skip it to cut costs. If your roofer's estimate doesn't include drip edge, ask why — and consider it a red flag about their attention to building code.
Signs Your Drip Edge Is Missing or Failing
- Rotting or stained fascia boards along the eaves
- Water stains on soffit panels
- Shingle edges curling upward at the eaves or rakes
- Visible gap between the last shingle and the gutter
- Wasp or bee nests forming at the roof-fascia junction
Related Questions
Is drip edge required on a new roof?
Yes. The International Residential Code (IRC R905.2.8.5) requires drip edge on all asphalt shingle roof installations. It's also required by most shingle manufacturers to maintain warranty coverage.
Can I add drip edge to an existing roof?
Yes, but it costs more than during a re-roof because the shingle edges need to be carefully lifted to slide the drip edge underneath. Expect $400–$1,000 for a full retrofit vs. $200–$600 during a re-roof.
What happens without drip edge?
Water wicks back under the last shingle via surface tension, soaking the fascia board and eave decking. Over years, this causes rot, soffit damage, and creates entry points for pests. It also voids most shingle manufacturer warranties.