How do I calculate drip edge for a roof?

Measure the linear feet of rake (sloped edges from eave to ridge) and eave (horizontal bottom edges). Add them together. Add 10% waste for cuts and overlaps. The total linear feet rounded up to the nearest stock length (typically 10 ft) is your order quantity per IRC R905.2.8.3.

What is the difference between rake and eave on a roof?

The eave is the horizontal lower edge of a sloped roof — the part that overhangs the wall and where gutters attach. The rake is the sloped edge from the eave up to the ridge or peak. A gable roof has two eaves and four rakes (two per gable end).

What does ASTM D3909 cover for drip edge?

ASTM D3909 specifies the asphalt-coated underlayment used with drip edges in IRC roofing assemblies. The drip-edge metal itself is specified under ASTM D7837 (galvanized steel) and ASTM B209 (aluminum). Most residential drip edge is 26-29 gauge galvanized or 0.024-inch aluminum.

How much drip edge do I need for a 1500 sq ft roof?

Depends on roof shape, not square footage. A typical 1500 sqft single-story gable home with 30-ft eaves and 18-ft rakes needs (2 × 30) + (4 × 18) = 132 linear feet of drip edge. Add 10% waste = 145 ft, round up to 15 pieces × 10 ft = 150 ft order.

What is the standard length of drip edge?

Most North American suppliers stock 10-ft and 10'6" (3.2 m) pieces of drip edge. Some big-box retailers carry 8-ft and 6-ft for residential repair. Commercial supply houses also offer 12-ft and 16-ft for high-end production roofing.

Should drip edge go over or under underlayment?

At eaves, drip edge goes UNDER the underlayment so water sheds onto it. At rakes, drip edge goes OVER the underlayment so wind-driven rain can't blow up under. This sequence is mandated by NRCA, GAF, and Owens Corning installation manuals and matches IRC R905.2.8.3.

How much overlap between drip edge pieces?

Minimum 2-inch overlap at all joints, with the upper piece on top so water can't enter the seam. Nail through both layers at the overlap. Most manufacturers specify 2-inch laps; SBS-modified high-wind zones may require 3-inch laps under Florida HVHZ rules.

What gauge of metal is drip edge?

26-gauge or 29-gauge galvanized steel for most residential. Aluminum runs 0.019-0.024 inches. Copper, used in historic restoration, runs 16-20 oz/sq ft. Galvanized lasts 25-30 years; aluminum 30-50 years; copper 60+ years per the Copper Development Association.

Can I install drip edge on a metal roof?

Yes, with metal-compatible profile. Standing-seam metal roofs typically use a manufacturer-supplied Type T or modified Type F drip edge matched to the panel system. Mixing galvanized drip with aluminum panels causes galvanic corrosion — match metals or use a stainless intermediary.

What is ice and water shield used with drip edge?

In cold climates, IRC R905.1.2 requires ice-and-water shield (a self-adhered membrane meeting ASTM D1970) extending at least 24 inches inside the exterior wall line. The shield laps over the drip edge at eaves and under at rakes — same sequence as the underlayment.

How many pieces of drip edge are in a box?

Drip edge is sold individually by the piece, not by the box. Some retailers ship pieces taped in bundles of 50 or 100; others sell singles. Always confirm piece count and length with the supplier before delivery — short shipments are common at high-volume yards.

Construction · Roofing

Drip Edge Calculator

Calculate drip-edge linear feet for any roof — gable, hip, shed, gambrel, or mansard. Choose your profile (Type L, T, F, D, or C), add waste, and the calculator returns the piece count rounded to the nearest 10-ft stock length per IRC R905.2.8.3 and ASTM D7837.

Profiles

L · T · F · D · C

Roof Shapes

5 types

Code

IRC R905.2.8.3

Standard

ASTM D7837

Quick Conversion

FROM (linear feet)

TO (10-ft pieces)1

Formula: pieces = ceil(LF / 10)

Roof, profile, dimensions

Roof Edge with Type L (Hemmed)

Gable roof

Eave LF

60.0

Rake LF

36.0

Total + Waste

105.6 lf

Pieces to Order

Roof Shape

Drip-Edge Profile

Most common: 90° bend, hemmed edge

Use: Asphalt shingle eaves, IRC R905.2.8.3

Eave (ft)

Rake (ft)

Piece Length (ft)

Waste %

Common Roof Presets

Drip-Edge Quick Order Table

Linear Ft Needed	+ 10% Waste	10-ft Pieces	Order LF
60	66.0	7	70
80	88.0	9	90
100	110.0	12	120
120	132.0	14	140
150	165.0	17	170
180	198.0	20	200
200	220.0	23	230
250	275.0	28	280
300	330.0	33	330
400	440.0	45	450
500	550.0	55	550

Pairs with ice-and-water shield calculator for full eave assembly.

Formula

Total_LF = (eave × eave_factor) + (rake × rake_factor) × (1 + waste%)

Pieces = ceil(Total_LF / piece_length)

Worked: gable, 30 ft eave, 18 ft rake, 10% waste, 10-ft pieces → (30 × 2 + 18 × 4) × 1.10 = 145.2 lf → 15 pieces.

Drip Edge Profile Reference

Profile	Description	Face × Back	Use
Type L (Hemmed)	Most common: 90° bend, hemmed edge	1.5″ × 1.5″	Asphalt shingle eaves, IRC R905.2.8.3
Type T (Tee)	T-shape with kickout — sheds water away from fascia	2.5″ × 1.75″	Tile, slate, high-rainfall regions
Type F (FL)	Hemmed L with longer face flange	3.5″ × 2″	Asphalt shingles in high-wind zones
Type D (D-style)	Wide-faced kickout for ice-dam regions	4.5″ × 2″	IRC R905.1.2 cold-roof / ice barrier zones
Type C (Classic L)	Pre-1990s L-style still spec'd in retrofit	2″ × 1.5″	Wood shake or historical reroof

How to Take Off Drip Edge

1
Pick roof shape
Gable, hip, shed, gambrel, mansard — each has a different eave-to-rake ratio. The tool applies the right multiplier.
2
Choose drip-edge profile
Type L is the universal default for asphalt. Use D for ice-dam zones, T for tile, F for high wind.
3
Enter eave and rake lengths
Measure once per side and let the multiplier handle counts. A gable has 2 eaves and 2 gable ends with 2 rakes each = 4 rakes total.
4
Set piece length and waste
Most stock is 10 ft. Bump waste to 15% if you have multiple hips, valleys, or complex roof breaks.
5
Read piece count
The tool rounds up to whole pieces. Save the takeoff to local history for crew handoff or future repair reference.

A short history of drip edge in residential roofing

In 2026, a residential reroof contractor in Maine submits a permit for a 2,400-square-foot gable retrofit. The local inspector cites IRC R905.2.8.3 and the recently-adopted 2024 IRC amendment requiring Type D drip edge in cold-roof zones. The contractor needs the linear feet of Type D — by eave and rake — to phone the supply house. Forty-seven seconds of arithmetic in this calculator versus twenty minutes of paper takeoffs.

Drip-edge metal has shielded roof edges since the 1880s, when galvanized sheet metal first entered widespread residential use. Edward Edmunds' 1881 patent on roll-formed galvanized roof flashing established the L-profile that still dominates the market. Through the early 20th century, drip edge remained an optional add-on — high-end builders installed it, tract builders skipped it.

The 1995 CABO One- and Two-Family Dwelling Code (predecessor to today's IRC) made drip edge optional but recommended at eaves only. The 2009 International Residential Code added a rake-edge recommendation. The 2012 IRC R905.2.8.3 made drip edge mandatory at both eaves and rakes for all asphalt-shingle roofs, with a minimum 2-inch flange on the roof deck and ¼-inch projection beyond the fascia.

The 2018 IRC tightened the spec to require corrosion-resistant metal meeting ASTM A653 (galvanized steel, G90 coating minimum), ASTM B209 (aluminum, 0.024 inch minimum), or stainless steel per ASTM A240. Copper drip edge meeting the Copper Development Association spec is accepted for historic-district reroofs. The 2024 IRC further tightened cold-region requirements by referencing ASTM D1970 ice-and-water shield underlap requirements at the drip edge.

Profile types — L, T, F, D, C — emerged from regional roofing traditions before the codes consolidated. Type L (hemmed L-shape) is the universal default. Type T (T-shape with longer kickout) sheds water further from the fascia and is preferred in tile and high-rainfall regions. Type F is a deep-faced L for high-wind zones. Type D extends to a 4½-inch face for ice-dam climates per IRC R905.1.2 — pairs with our ice-and-water shield calculator.

Installation sequence remains the most-missed code element. At eaves, drip edge installs UNDER the underlayment (felt or synthetic) so water sheds onto the metal. At rakes, drip edge installs OVER the underlayment so wind-driven rain cannot blow up under. The NRCA Roofing Manual, GAF Master Elite installation guide, Owens Corning specs, and CertainTeed manuals all agree on this sequence; getting it backwards is one of the most common fail-tag reasons for new construction roof inspections.

Waste factor matters more than most contractors estimate. A simple gable warrants 10% waste; complex hips, valleys, and multi-pitch roofs warrant 15-20%. Half a dozen extra pieces of drip edge cost less than a single return trip to the supply house. This calculator defaults to 10% and lets you bump it for complex geometries. For full roof estimating, pair this tool with our shingle calculator and our other construction calculators.

Drip Edge Installation Pro Tips

Eave first — UNDER the underlayment

At the eave, drip edge installs first, then felt/synthetic goes OVER it. Water sheds onto the metal, not behind it.

Rake last — OVER the underlayment

At the rake, underlayment goes first, then drip edge OVER it. Wind-driven rain can't blow up under.

Don't reverse the sequence

Eave-over and rake-under is the #1 fail-tag reason for new construction roof inspections. IRC R905.2.8.3 specifies the sequence; manufacturers void warranty if reversed.

Don't butt-joint without overlap

Minimum 2-inch overlap at every joint — upper piece on top. Nail through both layers. No overlap = leak path.

Bump waste to 15% for complex roofs

Hips, valleys, dormers, and gable ends all eat extra material at cuts. A simple gable runs 10% waste; complex multi-pitch runs 15-20%.

Match drip edge to climate

Type L universal; Type D for ice dams (IRC R905.1.2 zones); Type T for tile; Type F for high wind (140+ mph HVHZ). Don't under-spec.

What does the piece count actually mean for the job?

Fifteen pieces of 10-ft drip edge totals 150 linear feet — enough to cover a typical 1,500 sq ft gable home (60 lf eave + 72 lf rake = 132 lf base, plus 10% waste = 145 lf, ordered to 150 lf). The piece count is what you hand to the supply-house clerk; the linear feet is what your installer covers on the roof.

Waste matters more than most homeowners expect. Each butt joint requires a 2-inch overlap (lost waste), each rake-to-eave corner needs a mitered cut, and complex roofs with hips and valleys can lose 15-20% to cuts. A simple gable warrants 10% waste; a complex roof warrants 15%. Bidding low on drip edge waste is one of the most common mid-job material shortages.

For code compliance, the IRC R905.2.8.3 minimum is met by Type L profile in 26-gauge galvanized or 0.024" aluminum, installed eave-first under the underlayment, rake-last over the underlayment, with 2-inch overlaps. Anything more — Type D for ice dams, Type T for tile — exceeds code and accommodates regional conditions.

Drip edge metal comparison

Material	Spec	Life (yr)	Cost	Best use
Galvanized steel	ASTM A653 G90, 26-29 ga	25-30	$	Standard residential
Aluminum	ASTM B209, 0.019-0.024"	30-50	$$	Coastal, alkaline soils
Stainless steel	ASTM A240 304/316	75+	$$$	Marine, high-end
Copper	16-20 oz/sq ft	60-100+	$$$$	Historic restoration

Drip Edge FAQ

Have more questions? Contact us

Roofer & Inspector Reviews

4.9

Based on 5,380 reviews

“I shingle 90 roofs a year and drip-edge takeoff is the boring math that decides whether I'm short a piece at the end. This calculator separates rake from eave correctly and handles hip vs gable. Saves the run back to the supply house.”

Howard Pinchot

Master Roofer, Pinchot Roofing

May 2, 2026

“I fail-tag roofs that violate IRC R905.2.8.3 — drip edge missing or installed backwards. This tool teaches contractors the eave-under-rake-over rule correctly. Bookmarked for my pre-permit consultations.”

Elena Marchetti

Building Code Inspector, Maricopa County

April 8, 2026

“Customers walk in with napkin measurements asking how many pieces of drip edge. Now I send them this link from the counter. The profile selector covers Type L, T, F, D — matches our SKUs exactly.”

Jamal Owusu

Roofing Supply House Manager

March 15, 2026

“On gambrel and mansard projects the rake/eave count is non-trivial. The roof-shape selector here handles those shapes correctly. We used it on a 2025 Maine farmhouse build and the takeoff matched our installer's pull within one piece.”

Sasha Bonham-Reed

Custom Home GC

February 20, 2026

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