Is drip edge required by building code?

Yes. The IRC has required drip edge flashing on all eaves and rakes of asphalt shingle roofs since the 2012 code cycle. Even in jurisdictions using older code editions, most shingle manufacturers require drip edge for their warranty. It is one of the least expensive yet most important roofing components.

What profile of drip edge should I use?

Type C or D-style drip edge is the most common for residential roofing. It features a wider lower flange (1.5 to 2 inches) that extends water further from the fascia than Type A. Type F (also called gutter apron) has an extended face to work with gutters. For most homes, Type C/D in galvanized steel is the best balance of performance and cost.

How many pieces of drip edge do I need?

Measure all eave edges and rake edges in linear feet, then divide by the piece length (usually 10 feet). Account for a 2-inch overlap at each joint. For a simple gable roof on a 30x40 ft house: 60 ft of eaves + 2 rake lengths (using slope factor). Add 10% for waste and mitered corners.

Does drip edge go over or under the underlayment?

At the eaves, drip edge is installed directly on the sheathing, and the underlayment laps over it. At the rakes, drip edge is installed over the underlayment. This installation sequence ensures that any water running down the underlayment is directed onto the drip edge and away from the roof edge.

What material should I choose for drip edge?

Galvanized steel drip edge is the most common and cost-effective choice at $3 to $5 per 10-foot piece. Aluminum is lighter and does not rust but dents more easily. Copper drip edge is a premium option used on high-end homes and slate roofs. For coastal areas, aluminum or painted galvanized is recommended to resist salt air corrosion.

Can I install drip edge on an existing roof?

Adding drip edge to an existing roof without a full reroof is difficult because the shingles and underlayment need to lap over the eave drip edge correctly. It is best installed during a full reroofing project. If adding to an existing roof, slide the drip edge under the first course of shingles and nail through the top flange.

Drip Edge Calculator

Drip edge calculator: Estimate linear metres of flashing for your roof. Free tool — gives piece count for standard drip edge strips.

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Enter Your Measurements

How to Use This Calculator

1Measure all eave edges plus all rake edges.
2Enter drip edge piece length (standard 10 ft).
3Click Calculate.

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About This Material

Drip edge is an L-shaped or T-shaped metal flashing installed along the eaves and rake edges of the roof to direct water runoff away from the fascia board and into the gutters. It prevents water from wicking back under the sheathing edge, which is a common cause of fascia rot and soffit damage. Drip edge comes in standard 10-foot lengths in profiles Type A (small, simple L-shape), Type C/D-style (wider lower flange for better water diversion), and Type F (for use with gutters). Materials include galvanized steel (most common, $3-5 per 10-foot piece), aluminum ($4-7), and copper ($15-25 for premium applications). The IRC has required drip edge on all asphalt shingle roofs since the 2012 code cycle. Drip edge is available in a variety of colors to match the roof or fascia. At the eaves, drip edge goes under the underlayment; at the rakes, it goes over the underlayment — this sequencing is critical for proper water management.

Next Steps:

Shingle Calculator →Roofing Underlayment Calculator →

Installation Tips

•Install eave drip edge BEFORE underlayment, rake drip edge AFTER underlayment.
•Overlap pieces by 2 inches minimum.
•Nail every 12 inches.

Common Mistakes to Avoid

Installing rake drip edge before underlayment — underlayment must lap over rake drip edge.
Not overlapping pieces enough, allowing water infiltration.

Drip Edge Calculator

How to Use This Calculator

About This Material

Installation Tips

Common Mistakes to Avoid

Frequently Asked Questions

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