Shingles for a 18 × 44 ft roof at 8/12, simple gable
| Bundles3 per square | 32bundles |
|---|---|
| Squares (with waste) | 10.5sq |
| Roof area792 ft² footprint × 1.202 pitch factor | 952ft² |
| Pitch factor√(1 + (8/12)²) — pure geometry | 1.202 |
| Waste allowancetwo planes, cuts only at the rakes | 10% |
| Starter shingles124 ft of eave and rake | 2bundles |
| Hip & ridge cap44 ft of ridge | 3bundles |
| Underlaymentsynthetic, 10 squares per roll | 2rolls |
| Ice & water shieldeaves, 24″ inside the exterior wall line — check if your code requires it | 447ft² |
| Roofing nails — standard4 per shingle, about 3,351 nails | 24lb |
| Roofing nails — high wind6 per shingle — required in high-wind zones and by most warranties above 110 mph | 36lb |
| Walkable8/12 is past the point most people can stand on | No — staging needed |
Notes
- Footprint is not roof area, and the gap is bigger than people expect. A 18 × 44 ft footprint is 792 ft² on the ground but 952 ft² of roof at 8/12. Ordering off the footprint leaves you 1.6 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.
- 10% waste for a simple gable roof: two planes, cuts only at the rakes. 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 124 ft of eave and rake, 3 bundles of hip and ridge for 44 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 2,879 lb of old material to remove and skip.
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 18 × 44 ft footprint is 792 ft² on the ground. At 8/12 the roof over it is 952 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 1.6 squares short before waste is even counted.
Squares and bundles
10.5 squares with 10% waste for a simple gable roof — 32 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 124 ft of eave and rake. Hip and ridge cap: 3 bundles for 44 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 447 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.
24 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 2,879 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.
Nearby sizes
- Shingles for a 16 × 44 ft roof at 8/12, simple gable
- Shingles for a 20 × 44 ft roof at 8/12, simple gable
- Shingles for a 22 × 44 ft roof at 8/12, simple gable
- Shingles for a 18 × 42 ft roof at 8/12, simple gable
- Shingles for a 18 × 46 ft roof at 8/12, simple gable
- Shingles for a 18 × 40 ft roof at 8/12, simple gable
- Shingles for a 18 × 48 ft roof at 8/12, simple gable
- Shingles for a 18 × 44 ft roof at 6/12, simple gable
- Shingles for a 18 × 44 ft roof at 10/12, simple gable
- Shingles for a 18 × 44 ft roof at 5/12, simple gable
- Shingles for a 18 × 44 ft roof at 12/12, simple gable
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