How Many Shingles for a 2,400 Square Foot House?
Roofing squares needed
29.5 squares
A 2,400 square foot footprint, 60 by 40, at a 6/12 pitch with ten percent waste.
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How that number is worked out
These are the figures this page was built with and every line the calculator produces from them. Change anything above and all of it moves.
- Building length60 ft
- Building width40 ft
- Roof pitch, rise per 12 in6 /12
- Waste allowance10 %
- Ridge length, 0 if unknown60 ft
Roofing squares needed29.5 squares
| Footprint area | 2,400 sq ft |
|---|---|
| Slope multiplier at 6/12 | 1.12 x |
| Actual roof surface | 2,683 sq ft |
| Squares before waste | 26.8 |
| Squares with 10% waste | 29.5order to this number |
The material list this produces
| Shingles, bundles (3 per square) | 89 |
|---|---|
| Synthetic underlayment, rolls (10 sq each) | 3 |
| Starter strip, linear ft | 228 |
| Ridge cap, linear ft | 60 |
| Drip edge, linear ft | 200 |
| Roofing nails, lb | 65 |
Roof pitch compared
Pitch is the number most people guess at, and it is worth more shingles than any other input. Same house, five pitches.
| Roof pitch | Roofing squares needed |
|---|---|
| 4/12 | 27.8 squares |
| 6/12 | 29.5 squares |
| 8/12 | 31.7 squares |
| 10/12 | 34.4 squares |
| 12/12 | 37.3 squares |
What else matters here
Twenty four hundred square feet of footprint at 6/12 is 2,683 square feet of roof, 29.5 squares with waste, eighty nine bundles.
None of it is worth anything if the deck under it is soft. Modern sheathing is usually 7/16 inch OSB or half inch plywood over rafters or trusses at 24 inches on center, installed with a gap at the panel edges so it can expand. Older houses often have board sheathing with wide gaps, and some 1970s and 1980s houses have panels that have delaminated at the edges.
You only find out at tear off, which is why the price per sheet belongs in the contract before the job starts. Replace anything spongy underfoot, anything showing water staining around a penetration or a valley, and anything where a nail will not hold. A shingle nail into rotten sheathing has no withdrawal resistance, so that section of roof has no wind rating at all regardless of what the wrapper says.
What this calculator assumes
- Footprint times the slope multiplier gives the actual roof surface. A 6/12 roof is 11.8 percent larger than the ground it covers, which is the number most people forget.
- Three bundles per square is standard for both three tab and architectural shingles. Check your brand, a few premium lines run four.
- Synthetic underlayment is figured at 10 squares per roll, starter and ridge cap at one linear foot per foot.
Questions people ask
How many bundles of shingles for a 2,400 sq ft house?
About 89 bundles at a 6/12 pitch with ten percent waste, which is 29.5 squares.
What thickness sheathing goes under shingles?
Commonly 7/16 inch OSB or half inch plywood over framing at 24 inches on center, gapped at the panel edges. Local code and the truss spacing govern.
How do I know if roof decking needs replacing?
It is spongy underfoot, stained around penetrations and valleys, delaminated at the panel edges, or will not hold a nail. That is found at tear off, so agree a per sheet price beforehand.
The roofing calculator takes any dimensions you like and hands back the same list.