# Roofing shingle calculator

> 40′ × 30′ house, 6/12 roof: 1503 sq ft of roof is 50 bundles of shingles (architectural, 10% waste), with the underlayment, ice barrier, drip edge and nails. Squares, bundles, underlayment, ice barrier, drip edge, flashing, vents and nails for an asphalt shingle roof.

## What to buy (40′ × 30′ house, 6/12 roof)

Every line shows the quantity to buy and how StudSheet got it: the spacing, the waste and the package size, so you can check it before the supply house or the quote.

| Buy | Material | How StudSheet counts it | What it is for |
|---|---|---|---|
| **50 bundles** | Architectural shingles (laminated) (3 bundles a square) | 42′ × 32′ with the overhangs × 1.118 for the 6/12 slope = 1503 sq ft, + 10% waste (gable roof) = 16.53 squares × 3 bundles a square. Read the wrapper: some bundles cover a little less. | Two-layer asphalt shingles; most cover a square (100 sq ft) with 3 bundles — read the wrapper. |
| **2 bundles** | Starter strip shingles (about 105 ft a bundle) | 84 ft of eaves + 72 ft of rakes + 5% ÷ 105 ft a bundle. Starter on the rakes too keeps the edge shingles down in wind. | The first course at the eaves and rakes: its sealant strip holds the edge of the first shingles down in wind. |
| **2 bundles** | Hip and ridge cap shingles (about 30 ft a bundle) | 42 ft of ridge + 5% ÷ 30 ft a bundle (25–33 ft by brand). | Pre-bent caps for the ridge and hips; about 25–33 ft a bundle by brand. |
| **2 rolls** | Synthetic roof underlayment (10-square rolls) | 1503 sq ft ÷ 900 sq ft a roll after laps. | Woven, tear-resistant underlayment that replaced felt; 10-square rolls, fastened with cap nails. |
| **1 box** | Plastic cap nails (2,000 a box) | About one per 2 sq ft of underlayment — follow the pattern printed on the roll. | Nails with a wide plastic washer that hold underlayment without tearing it. |
| **18 pieces** | Drip edge (10′ pieces) | 84 ft of eaves + 72 ft of rakes, each run in 10′ pieces lapped 2″. The IRC requires it at the eaves and rakes (R905.2.8.5). | Metal edge at the eaves and rakes that throws water clear of the fascia. |
| **2 boots** | Pipe boot (vent flashing) (match each pipe size) | A new boot on every plumbing vent; old rubber collars crack in the sun. | Flashing with a rubber collar for a plumbing vent pipe; match the pipe size. |
| **10 sections** | Shingle-over ridge vent (4′ sections) | 40 ft of ridge (stopping 1′ short of each end) at about 18 sq in per foot = 720 sq in. Needed: 288 sq in up high — half of 1/300 of the attic floor when about half is high and half low (IRC R806.2; 1/150 otherwise) for 1200 sq ft of attic. Match it with at least as much intake at the soffits. | Vent along the ridge, covered with cap shingles; the label gives its net free area per foot. |
| **1 box** | Roofing nails, coil (1¼″ galvanized, 7,200 a box) | ≈4,595 nails: 4 a shingle × 66 shingles a square × 16.7 squares, plus the starter. Long enough to go ¾″ into the deck or through it. | Galvanized roofing nails for a coil roofing nailer; long enough to go ¾″ into the deck or through it. |
| **1 small box** | Roofing nails, coil (the length on the vent’s label) | The cap shingles over the ridge vent need longer nails — usually 2″ or more; the vent’s label says. | Galvanized roofing nails for a coil roofing nailer; long enough to go ¾″ into the deck or through it. |
| **3 tubes** | Roofing sealant (10 oz tubes) | Flashing edges, exposed nail heads at the ridge, and pipe boots — a dab, not a substitute for flashing. | Asphalt or polymer sealant for flashing edges, exposed nail heads and cap shingles — not a substitute for flashing. |

### In Canada (12.19 m × 9.14 m house, 6/12 roof)

Set to Canada, the Sheet works the job out again for Ontario: metric sizes, bag sizes, the frost depth and the code notes. It doesn't just convert feet to meters. The first lines:

- **50 bundles, Architectural shingles (laminated):** 12.80 m × 9.75 m with the overhangs × 1.118 for the 6/12 slope = 139.6 m², + 10% waste (gable roof) = 16.53 squares × 3 bundles a square. Read the wrapper: some bundles cover a little less.
- **2 bundles, Starter strip shingles:** 25.60 m of eaves + 21.81 m of rakes + 5% ÷ 32 m a bundle. Starter on the rakes too keeps the edge shingles down in wind.
- **2 bundles, Hip and ridge cap shingles:** 12.80 m of ridge + 5% ÷ 9.1 m a bundle (7.62–10.06 m by brand).
- **2 rolls, Synthetic roof underlayment:** 116.2 m² (the roof less the eave protection) ÷ 83.6 m² a roll after laps. The OBC doesn’t require underlay under shingles at 4/12 and steeper (9.26.6), but shingle makers’ warranties do.
- **1 box, Plastic cap nails:** About one per 0.2 m² of underlayment — follow the pattern printed on the roll.
- **2 rolls, Ice and water barrier (self-adhered):** 25.60 m of eaves = 25.60 m + 5% for laps ÷ 20.3 m a roll. At the eaves: up to 914 mm along the slope.

## The steps, in order

> **PRO STEP: most of it is DIY-friendly; one step needs a licensed pro.** About 84–127 hours of work for this example.

1. Before you start: order materials and the dumpster, check the forecast for dry, calm days, and cover plants, the AC unit and the driveway with tarps.
2. Set the ladder on firm ground, 1 out for every 4 up, tied off and 3 ft above the eaves. Harness on, roof anchor into a rafter near the ridge, before any other work.
3. Tear off one section at a time, only what you can dry in today: shingles, underlayment and nails, down to the deck.
4. Walk the deck: replace soft or rotten sheathing, drive or pull every nail, sweep it clean.
5. Drip edge along the eaves first, nailed every 12″ or less, pieces lapped 2″.
6. Peel and stick: ice barrier along the eaves (if required), up to 3′ 5″ along the slope (2 courses).
7. Underlayment over the rest of the deck, from the eaves up, laps as printed on the roll, cap-nailed. Then drip edge along the rakes, over the underlayment.
8. Starter strip along the eaves and rakes, sealant strip at the edge, overhanging the drip edge as the wrapper shows.
9. Snap chalk lines and shingle from the eaves up: 4 nails a shingle in the nail line, offsets as the wrapper shows; set pipe boots as the courses reach them.
10. Cut the ridge slot as the vent’s label says, stopping 1 ft short of each end; nail the ridge vent.
11. Hip and ridge cap: hips from the bottom up, then the ridge, working away from the wind, with the longer nails through the vent.
12. Clean up: magnetic sweep the yard, beds and driveway twice, and haul the dumpster.

## Tools (22)

Must-have tools first, then the ones that help and the ones to rent for the day.

| Tool | Need | Why |
|---|---|---|
| **Fall-protection kit** | **Must have** | Harness, lanyard and a roof anchor screwed into a rafter — tie off before you step off the ladder |
| **Extension ladder (24 ft)** | **Must have** | Eaves about 10 ft up: a ladder 7–10 ft longer, tied off, 3 ft above the edge, 1 out for every 4 up |
| **Ladder stabilizer (standoff)** | Good to have | Holds the ladder off the gutter |
| **Roof brackets (roof jacks)** | Good to have | With a 2× plank: a toe-hold at the eaves and a shelf for bundles, ≤ 8 ft apart, nailed into rafters |
| **Shingle remover** | **Must have** | Pries shingles and nails up together |
| **Pry bar** | **Must have** | Old flashing and stubborn nails |
| **Roll-off dumpster** | Rent | ≈4,508 lb of old roofing (15 squares × 1 layer × about 300 lb): a 15-yard roll-off — tell the hauler it’s shingles; most cap the weight |
| **Heavy-duty tarps** | **Must have** | Over plants, the AC unit and the driveway — and over open deck if rain comes |
| **Coil roofing nailer** | Rent | Or hand-nail with a roofing hatchet: about 264 nails a square |
| **Air compressor + hose** | Rent | Runs the roofing nailer |
| **Utility knife + blades** | **Must have** | Hook blades cut shingles from the back |
| **Chalk line** | **Must have** | Straight courses: snap a line every few courses |
| **Tape measure (25 ft)** | **Must have** | The red boxes every 16″ on the blade are stud spacing. |
| **Aviation snips** | **Must have** | Drip edge, valley metal and step flashing |
| **Framing hammer** | **Must have** | Nails, taps and persuades. |
| **Caulk gun** | **Must have** | Roofing sealant |
| **Circular saw** | **Must have** | Cuts the ridge vent slot and deck repairs |
| **Magnetic nail sweeper** | **Must have** | Run it over the yard and driveway twice — roofing nails find tires and feet |
| **Safety glasses** | **Must have** | Every cut, every nail, every time. |
| **Work gloves** | **Must have** | Tack strip, block and lumber shred hands. |
| **Knee pads** | Good to have | Flooring and tile are all knees. |
| **Roof pitch gauge** | Good to have | Confirms the pitch before you order |

## Mistakes and how the math works

### Mistakes that cost a callback or a second trip

- **High or crooked nails:** Nails above or below the nail line, or overdriven, let shingles blow off and void the wind warranty. Set the nailer depth on a scrap first.
- **Opening more than you can dry in:** A storm on bare deck soaks the ceilings below. Tear off only what you can cover by evening.
- **Old step flashing, no kick-out:** Roof-to-wall leaks rot the wall behind the siding for years before they show. New step flashing at every course, a kick-out at the bottom.
- **More exhaust than intake:** A ridge vent with blocked or missing soffit vents pulls air from the house instead of the eaves. Match the intake.
- **Working wet, frosty or windy:** Wet underlayment is slick and cold shingles crack. Dry, calm days only — and never alone.

### What the calculator assumes

- Roof area = footprint with the overhangs × the slope factor √(1 + (rise ÷ 12)²): 1.118 at 6/12 (26.6°). All slopes at one pitch.
- A square is 100 sq ft. Shingles: 3 bundles a square (architectural and 3-tab), 4 for designer — read the wrapper. Waste 10% gable, 15% hip, 5% shed, +5% with valleys.
- Starter about 105 ft a bundle (Owens Corning Starter Strip Plus); hip and ridge cap about 30 ft a bundle (25–33 ft by brand).
- Underlayment: synthetic 10-square rolls, about 900 sq ft after laps; two layers below 4/12 (IRC R905.1.1). Ice barrier: 36″ × 66.7 ft rolls (200 sq ft), 3½″ side laps, valleys lined 36″ wide.
- Ice barrier (IRC R905.1.2): from the eaves to 24″ inside the exterior wall, measured level; at least 36″ up the slope on 8/12 and steeper.
- Drip edge in 10 ft pieces lapped 2″. Nails: 4 a shingle, 66 architectural or 80 3-tab shingles a square; coil boxes of 7,200.
- Ventilation: 1/300 of the attic floor when about half is high and half low (IRC R806.2; 1/150 otherwise). Ridge vent about 18 sq in per foot and box vents about 50 sq in each — read the label.
- Tear-off: about 300 lb a square per layer (250–450 lb by shingle); dumpster sizes are typical — your hauler sets the weight limit.
- Hours: pro labor-hours from typical crew rates (tear-off about 0.6 h a square per layer, shingling 1.6 h a square), more for steep and tall roofs; doing it yourself takes 2–3 times as long.

## Code, permits and safety

The Sheet sets its code notes for the job's state or province. These are New Jersey's and Ontario's; the [code reference](https://studsheet.com/codes) has more. Always confirm with your building department.

- **Most homeowners hire this out:** Falls are the leading cause of death in construction (OSHA), and roofs are where many happen. Paid crews must be protected from falls from 6 ft up (OSHA). If you do it yourself: a harness tied to a roof anchor, roof brackets with a plank along the eaves, soft-soled shoes, a helper on the ground, dry and calm days only — and only open what you can dry in by evening.
- **Ice barrier: ask your town:** The IRC’s ice barrier (R905.1.2), in practice a peel-and-stick membrane, runs from the eaves to at least 24″ inside the exterior wall. New Jersey’s code office requires it where January averages 25°F or colder, which in New Jersey means Sussex County (DCA Bulletin 07-3). Elsewhere in the state it’s optional — and cheap insurance where ice dams happen. We listed it as optional: answer “Ice barrier at the eaves” above if you want it. Confirm with your building department.
- **No permit for a reroof in New Jersey:** Replacing the roof covering on a detached one- or two-family house is ordinary maintenance in New Jersey, so it needs no permit (N.J.A.C. 5:23-2.7). Attached homes and any framing work are different: ask your town’s construction office.
- **Eave protection required:** The OBC (9.26.5) asks for eave protection on shingle roofs over heated space: from the edge at least 900 mm up the slope, and to at least 300 mm past the inside face of the exterior wall. Exceptions: unheated garages and porches, overhangs deeper than 900 mm, and areas with 3,500 heating degree-days or fewer. Confirm with your building department.
- **Permit: usually not for the same shingles:** Re-shingling with the same kind of roofing usually needs no building permit (Niagara Falls, Ontario, for example); a different roofing material or repairs to the structure do. Ask your municipality’s building department.

## Questions

### What materials do I need to shingle a roof?

For the worked example, a 40′ × 30′ house, 6/12 roof, the Sheet counts 11 lines with waste included, starting with architectural shingles (laminated) (50 bundles), starter strip shingles (2 bundles), hip and ridge cap shingles (2 bundles), synthetic roof underlayment (2 rolls). Each line's math is in the table above. Put in your own sizes in the [roof calculator](https://app.studsheet.com/p/roofing) and every line is counted again.

### How long does it take to shingle a roof, and can I do it myself?

About 84 to 127 hours for the worked example, in 12 steps. StudSheet stamps it **PRO STEP**: dIY with a pro for one step.

### What tools do I need to shingle a roof?

22 in all. The must-haves start with fall-protection kit, extension ladder (24 ft), shingle remover, pry bar, heavy-duty tarps, utility knife + blades. On the Sheet you mark each one as owned, to buy or to rent.

## Ask about it

Stuck while you shingle a roof? Ask in the [Shingle roofs group](https://studsheet.com/forum/roofing) of the StudSheet community with this Sheet attached. Homeowners who've done it and verified pros answer, and anyone can read it.

## More roofing & siding Sheets

- **[Roofing, siding and gutters for contractors](https://studsheet.com/trades/roofing)**: run this takeoff at your own prices, send the estimate, and get it signed and the deposit paid.
- **[Install or replace siding](https://studsheet.com/sheets/siding)** (40′ × 25′ house, 2 stories): Squares of vinyl, fiber-cement or engineered-wood lap siding for your house, with house wrap, starter, J-channel, corners, trim and nails — from the same answers as the exterior paint Sheet.
- **[Gutters and downspouts](https://studsheet.com/sheets/gutters)** (84′ of gutter, 4 downspouts): Gutter size, downspouts sized to the roof they drain, hangers, corners, end caps, outlets, elbows and extensions — sectional for DIY or seamless by the foot.
- **[All 45 Sheets](https://studsheet.com/sheets)**, across 16 trades.
- **[Code reference](https://studsheet.com/codes):** frost depths, guard heights, stairs, retaining walls.