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Drip Edge Calculator

Sticks for the eaves and the rakes, lap already off.

One profile; two profiles are two counts.

24' · 288 in · 24 ft · 7.3152 m

20' · 240 in · 20 ft · 6.096 m

4/12 · 18.4° · 33.3%

1' · 12 in · 1 ft · 0.3048 m

1' · 12 in · 1 ft · 0.3048 m

602.94 ft²

Cutting waste on the covering — the shingles, or the metal panels. The makers allow 10% on a gable roof and 15% on a hip, where every course runs into a hip at an angle; CertainTeed's own manual says 10% is generous on a large simple roof. It moves the covering only — the starter, the cap, the drip edge and the underlayment are cut to length, not off a square.

This page recalculates as you type. There is no Calculate button.

Answer

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Sticks of drip edge

11 sticks

602.94 ft² of roof, 6.03 squares, 20 bundles

Bundles of shingles 20 bundles
Roofing squares 6.03 squares
Roof area, up the slope 602.94 ft²
What the list comes to $1,254.50
More numbers
Footprint, on the ground 572 ft²
Slope factor 1.0541
Bundles of starter 1 bundles
Bundles of ridge cap 1 bundles
Rolls of underlayment 1 rolls
Nails 1,544 nails
DrawingThe project drawn to scale. Roof 1: 24' × 20'.24'20'Roof 1

Buying noteNo ice barrier is on this list. The code requires one where your town's table says so — look up Table R301.2 for where you are, and switch it on if it says yes.

Breakdown

Plane Measurements Qty Area on the slope Share
Roof 1 24' × 20' × 4/12 × 1' × 1' Add ×1 602.94 ft²

What to buy

Buying noteNo ice barrier is on this list. The code requires one where your town's table says so — look up Table R301.2 for where you are, and switch it on if it says yes.

Ways to buy the shingles

Every bundle is worked out, each rounded up to whole bundles; pick the one you will buy. The three are different shingles, not three sizes of one, so a mix means two products on one roof — buy a mix only if you meant to.

20 × bundles of HDZ Bundles 20 Left over 3.36 ft² Weight 1,556 lb Cost $840.00 Reference price $42.00. Type your store's.
21 × bundles of Oakridge Bundles 21 Left over 25.56 ft² Weight 1,512 lb Cost $798.00 Reference price $38.00. Type your store's.
20 × bundles of Landmark Bundles 20 Left over 3.36 ft² Weight 1,500 lb Cost $880.00 Reference price $44.00. Type your store's.

Shopping list

20 20 × bundles of HDZ $840.00
1 1 × bundles of OC starter $54.00 Reference price $62.00. Type your store's. Reference price $54.00. Type your store's.
1 1 × bundles of ProEdge $56.00 Reference price $48.00. Type your store's. Reference price $56.00. Type your store's.
11 11 × sticks of drip edge $148.50 Reference price $13.50. Type your store's.
1 1 × rolls of synthetic $128.00 Reference price $128.00. Type your store's.
2 2 × 5 lb boxes of nails $28.00 Reference price $78.00. Type your store's. Reference price $14.00. Type your store's. Reference price $5.00. Type your store's.
Ticked items $1,254.50

Untick what you already have. Each row has its price beside it — type what your store charges.

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Standards

We hold the criteria and the clause, not the wording of the standard.

Meets IRC 2021 · R905.2.2

At 4/12 this roof is steep enough for asphalt shingles.

Meets IRC 2021 · R905.2.2

At 4/12 a single layer of underlayment is enough.

Meets IRC 2021 · R905.2.8.5

110' of drip edge covers the eaves and the rakes.

Not checked IRC 2021 · R905.1.2

The code requires an ice barrier only where your local Table R301.2 says so, and we hold no table by town. Look yours up and switch it on.

How this was worked out

Every number below is yours. Each constant links to the row where you can change it.

Roof 1 26' × 22' × 1.0541 (4/12) 602.94 ft²
Squares of roof 602.94 ft² ÷ 100 ft² 6.03 squares

Change:A roofing square

With cutting waste 602.94 ft² × (1 + 10%) 663.24 ft²
Bundles to buy 663.24 ft² ÷ 33.33 ft² 20 × bundles of HDZ · 3.36 ft² over

Change:GAF HDZ bundle coversOC Oakridge bundle coversCT Landmark bundle covers

Starter course 52' ÷ 105 lf 1 × bundles of OC starter

Change:GAF Pro-Start bundle runsOC starter bundle runs

Ridge cap 26' ÷ 33 lf 1 × bundles of ProEdge

Change:Seal-A-Ridge bundle runsOC ProEdge bundle runs

Drip edge 98' 4 9/16" ÷ (10' − 2") 11 sticks

Change:A stick of drip edgeDrip edge lap

Underlayment 602.94 ft² ÷ (1,001 ft² × (1 − 10%)) 1 rolls

Change:Synthetic roll coversLaps take off a roll

Nails 6.03 squares × 256 1,544 nails → 2 × 5 lb boxes of nails

Change:Nails a square

What it comes to 20 × $42.00 + 1 × $54.00 + 1 × $56.00 + 11 × $13.50 + 1 × $128.00 + 2 × $14.00 $1,254.50

Assumptions

Every one of these is editable. Change one and the answer changes with it.

Assumption Value Confidence
A roofing squareA roofing square is 100 ft² by the trade's definition; every shingle wrapper and every estimate is quoted in them. ≈ ft²/square Trade convention
GAF HDZ bundle coversGAF Timberline HDZ: 33.33 ft² a bundle, three bundles to the square, from the Home Depot listing. ft²/bundle From a data sheet or an agency document
OC Oakridge bundle coversOwens Corning Oakridge and Duration: 32.8 ft² a bundle. Three of them cover 98.4 ft², not 100, which is why this page never counts three bundles to the square. ft²/bundle From a data sheet or an agency document
CT Landmark bundle coversInferred, not printed: the CertainTeed Landmark data sheet gives 66 shingles to the square, and three bundles to the square is the trade's convention, so a bundle covers 100/3 ft². The sheet does not state a coverage per bundle. ~ ft²/bundle Derived or single-supplier
GAF Pro-Start bundle runsGAF Pro-Start starter strip: 120.33 linear feet a bundle, from GAF's own product page. lf/bundle From a data sheet or an agency document
OC starter bundle runsOwens Corning Starter Strip Plus: 105 linear feet a bundle, data sheet dms/10011118. lf/bundle From a data sheet or an agency document
Seal-A-Ridge bundle runsGAF Seal-A-Ridge ridge cap: 25 linear feet a bundle, from the Home Depot listing. lf/bundle From a data sheet or an agency document
OC ProEdge bundle runsOwens Corning ProEdge ridge cap: 33 linear feet a bundle, from the Home Depot combination listing. lf/bundle From a data sheet or an agency document
A stick of drip edgeDrip edge is sold in 10 ft sticks in every profile. Gibraltar Building Products catalog 2026 (AWC020926B) page 5. ft From a data sheet or an agency document
Drip edge lapDrip edge sticks lap at least 2 in, so a 10 ft stick covers 9 ft 10 in. JLC on IRC R905.2.8.5, which requires drip edge at eaves and rakes but gives the lap as a minimum rather than a number. ≈ in Trade convention
Synthetic roll coversOwens Corning ProArmor synthetic underlayment: 1,001 ft² a roll, from the Home Depot combination listing, read 14/10/2026. ft²/roll From a data sheet or an agency document
Laps take off a rollWhat the head and side laps take off a roll's printed area. A 36 in felt lapped 2 in at the head over a 36 in exposure loses about a tenth; synthetic sheets print a lap line at much the same place. An editable single number because the exact loss depends on the exposure the installer works to. ~ ratio Derived or single-supplier
Nails a squareGAF: 256 nails a square. The figure is theirs; how it divides over shingles and courses is not stated and is not inferred here. nails/square From a data sheet or an agency document
Shallowest pitch for shinglesThe floor for asphalt shingles: at this pitch and above they may be used, and from here up to the next limit the underlayment doubles. IRC R905.2.2 states both. CertainTeed's Landmark data sheet is one step stricter - "greater than 2:12" - so a roof at exactly 2:12 passes here and not on their sheet; this box is where you put their figure. rise per 12 From a data sheet or an agency document
Double underlayment belowBelow this pitch, and at or above the shallowest pitch for shingles, the underlayment has to be doubled. IRC R905.2.2; CertainTeed's Landmark data sheet states the same range. rise per 12 From a data sheet or an agency document
Hire a roofer aboveWhere a roof stops being walkable without staging. Not a code limit: it is the slope at which this page says to get a quote rather than climb up. 6:12 itself is walkable, so the warning starts above it. ≈ rise per 12 Trade convention
Cutting waste, hip15% on a hip roof: four planes means a cut at every hip. Same sources as the gable figure. A hip roof needs no second 'hip factor' on its area - the slope factor already covers the whole surface - only more cutting. ≈ ratio Trade convention

Drip edge is required, and nobody counts it

Drip edge is the metal angle at the edge of a roof that throws water clear of the fascia. The residential code has required it at eaves and rakes since the 2012 edition, with a lap of at least 2 inches where sticks meet.

It is sold in 10 foot sticks, every profile. With a 2 inch lap, a stick covers 9 feet 10 inches, so the count is the eave and rake length divided by 9.83 — not by 10.

Eave + rake Sticks
60 ft7
100 ft11
147 ft (40 × 30 gable at 6:12)15
140 ft (the same as a hip roof)15
200 ft21

Why the rake is longer than it looks

A rake runs up the slope. On a 40 by 30 foot gable roof at 6:12 each rake is 15 feet of plan times the 1.118 slope factor — 16 feet 9 inches — and there are four of them, two per gable end. That is 67 feet of rake against 80 feet of eave: nearly half the drip edge, and the part a calculator working from area alone cannot see.

A hip roof has no rake at all. Its eave runs the whole perimeter instead, so a 40 by 30 hip roof needs drip edge for 140 feet — slightly less than the gable, all of it at the eave.

Eave first or rake first

The order is not arbitrary. Drip edge at the eave goes under the underlayment, so water on top of the underlayment runs out over the metal. At the rake it goes over the underlayment, so wind-driven water running down the rake cannot get behind it. Getting it the other way round puts water under the felt at the eave, which is the one place it must not be.

Profiles

The common ones are the L-shaped type (sometimes called type C) and the one with a kick-out at the bottom (type D, or "D-style"), which throws water further from the fascia and is required in some jurisdictions. Both come in 10 foot sticks and both are counted the same way. This page counts one profile; if you are using a different one at the rake from the eave, count the two lengths separately.