Shingles for a 32 × 34 ft roof at 8/12, complex
| Bundles3 per square | 48bundles |
|---|---|
| Squares (with waste) | 15.7sq |
| Roof area1,088 ft² footprint × 1.202 pitch factor | 1,308ft² |
| Pitch factor√(1 + (8/12)²) — pure geometry | 1.202 |
| Waste allowancevalleys, dormers and changes of plane all waste material | 20% |
| Starter shingles132 ft of eave and rake | 2bundles |
| Hip & ridge cap72 ft of ridge and hips | 4bundles |
| Underlaymentsynthetic, 10 squares per roll | 2rolls |
| Ice & water shieldeaves, 24″ inside the exterior wall line — check if your code requires it | 476ft² |
| Roofing nails — standard4 per shingle, about 5,021 nails | 36lb |
| Roofing nails — high wind6 per shingle — required in high-wind zones and by most warranties above 110 mph | 54lb |
| Walkable8/12 is past the point most people can stand on | No — staging needed |
- Footprint width
- 32 ft
- Footprint length
- 34 ft
- Pitch
- 8 /12
- Roof type
- complex
Footprint is not roof area
This is where roofing estimates go wrong, and they go wrong in the direction that leaves you short on a Saturday.
A 32 × 34 ft footprint is 1,088 ft² on the ground. At 8/12 the roof over it is 1,308 ft² — the pitch factor is 1.202, which is √(1 + (8/12)²). Pure geometry, no fudge factor.
Order off the footprint and you are 2.2 squares short before waste is even counted.
Squares and bundles
15.7 squares with 20% waste for a complex roof — 48 bundles at three per square.
Waste is not one number. A simple gable cuts only at the rakes. A hip roof cuts along every hip. A cut-up roof with valleys and dormers throws away a fifth of what you buy, and no amount of careful planning changes that.
The two lines everyone forgets
Starter: 2 bundles for 132 ft of eave and rake. Hip and ridge cap: 4 bundles for 72 ft.
These are separate products, not field shingles cut down. Using field shingles as starter voids most manufacturers' wind warranties, which is discovered at the claim rather than at the purchase.
Underneath
2 rolls of synthetic underlayment, and 476 ft² of ice-and-water shield at the eaves — 24 inches inside the exterior wall line, which is what the IRC asks for where it applies. Check whether your jurisdiction requires it.
36 lb of roofing nails at four per shingle, or lb at six for a high-wind zone.
Two things to price before you decide it is DIY
Tear-off: about 4,315 lb of old shingle to strip and skip.
And access. Above 8/12 a roof stops being walkable for most people, and roof jacks, planks or scaffolding cost real money that belongs in the estimate before you decide this is a DIY job.
Notes
- **Footprint is not roof area, and the gap is bigger than people expect.** A 32 × 34 ft footprint is 1,088 ft² on the ground but **1,308 ft²** of roof at 8/12. Ordering off the footprint leaves you 2.2 squares short — and that is before waste.
- The pitch factor is √(1 + (rise/12)²). There is no estimate in it and no manufacturer fudge — it is the hypotenuse. 8/12 gives 1.202.
- 20% waste for a complex / cut-up roof: valleys, dormers and changes of plane all waste material. A simple gable wastes least because the only cuts are at the rakes; every hip and valley adds a run of angled cuts that produce offcuts nothing else uses.
- Starter and cap are separate purchases, and they are the two lines that get left off estimates. 2 bundles of starter for 132 ft of eave and rake, 4 bundles of hip and ridge for 72 ft. Using field shingles as starter voids most manufacturer wind warranties.
- At 8/12 this is not a walkable roof for most people. Roof jacks and planks, or scaffolding — and that cost belongs in the estimate before you decide whether this is a DIY job.
- Tear-off is the other half of the job. A single layer of asphalt shingle weighs 200–350 lb per square, so this roof carries about 4,315 lb of old material to remove and skip.
Nearby sizes
- Shingles for a 30 × 34 ft roof at 8/12, complex
- Shingles for a 34 × 34 ft roof at 8/12, complex
- Shingles for a 28 × 34 ft roof at 8/12, complex
- Shingles for a 34 × 36 ft roof at 8/12, complex
- Shingles for a 32 × 32 ft roof at 8/12, complex
- Shingles for a 32 × 36 ft roof at 8/12, complex
- Shingles for a 30 × 32 ft roof at 8/12, complex
- Shingles for a 32 × 38 ft roof at 8/12, complex
- Shingles for a 32 × 34 ft roof at 6/12, complex
- Shingles for a 32 × 34 ft roof at 10/12, complex
- Shingles for a 32 × 34 ft roof at 5/12, complex
- Shingles for a 32 × 34 ft roof at 12/12, complex
- Shingles for a 32 × 34 ft roof at 8/12, hip
- Shingles for a 32 × 34 ft roof at 8/12, simple gable
Read more
- Cost to Replace a Roof by Material: Price per Square Against Years of ServiceThe cheapest roof and the cheapest roof per year are rarely the same product, and which one you want depends on how long you are staying.
- Roof Replacement Cost per Square: What the Number Contains, and What Moves ItPer-square pricing is the only way to compare two roofing quotes honestly. Most homeowners are handed a lump sum instead, which hides where the money goes.
- How Many Bundles of Shingles per Square? Three, Except When It Is Four or FiveThree bundles per square is the answer for most of what is stacked at the store. It is wrong often enough to be worth checking before you load the truck.
- How to Measure a Roof From the Ground, Accurately Enough to Order FromYou need three measurements and none of them require getting on the roof. Two of them can be taken from the driveway.