How Many Shingles for an 800 Square Foot House?
Roofing squares needed
9.8 squares
An 800 square foot footprint, 40 by 20, 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 length40 ft
- Building width20 ft
- Roof pitch, rise per 12 in6 /12
- Waste allowance10 %
- Ridge length, 0 if unknown40 ft
Roofing squares needed9.8 squares
| Footprint area | 800 sq ft |
|---|---|
| Slope multiplier at 6/12 | 1.12 x |
| Actual roof surface | 894 sq ft |
| Squares before waste | 8.9 |
| Squares with 10% waste | 9.8order to this number |
The material list this produces
| Shingles, bundles (3 per square) | 30 |
|---|---|
| Synthetic underlayment, rolls (10 sq each) | 1 |
| Starter strip, linear ft | 144 |
| Ridge cap, linear ft | 40 |
| Drip edge, linear ft | 120 |
| Roofing nails, lb | 22 |
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 | 9.3 squares |
| 6/12 | 9.8 squares |
| 8/12 | 10.6 squares |
| 10/12 | 11.5 squares |
| 12/12 | 12.4 squares |
What else matters here
Eight hundred square feet of footprint at 6/12 is 894 square feet of roof, 9.8 squares with waste, thirty bundles.
Thirty bundles comes from the rule that three bundles make a square, which holds for almost every three tab and architectural shingle sold in the United States. It is not a law of nature, it is what the manufacturers settled on so that a bundle stays light enough for one person to carry up a ladder.
Some premium and designer lines break it. Heavy laminated shingles and anything imitating slate or shake commonly run four or even five bundles per square, because the shingle itself is thicker and fewer fit in a package. The coverage is printed on the wrapper in square feet, so read it before multiplying, and never mix brands or production runs on one roof: exposure and color both move between them.
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 an 800 sq ft house?
About 30 bundles at a 6/12 pitch with ten percent waste, which is 9.8 squares.
How many bundles are in a square of shingles?
Three for almost all three tab and architectural shingles. Premium and designer lines often run four or five, and the coverage is printed on the bundle wrapper.
Can I mix shingle brands on one roof?
No. Exposure, thickness and color vary between brands and even between production runs, so a mixed roof shows the difference and loses the manufacturer warranty.
The roofing calculator takes any dimensions you like and hands back the same list.