How Many Shingles for a 1,800 Square Foot House?
Roofing squares needed
22.1 squares
An 1,800 square foot footprint, 60 by 30, 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 width30 ft
- Roof pitch, rise per 12 in6 /12
- Waste allowance10 %
- Ridge length, 0 if unknown60 ft
Roofing squares needed22.1 squares
| Footprint area | 1,800 sq ft |
|---|---|
| Slope multiplier at 6/12 | 1.12 x |
| Actual roof surface | 2,012 sq ft |
| Squares before waste | 20.1 |
| Squares with 10% waste | 22.1order to this number |
The material list this produces
| Shingles, bundles (3 per square) | 67 |
|---|---|
| Synthetic underlayment, rolls (10 sq each) | 3 |
| Starter strip, linear ft | 204 |
| Ridge cap, linear ft | 60 |
| Drip edge, linear ft | 180 |
| Roofing nails, lb | 49 |
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 | 20.9 squares |
| 6/12 | 22.1 squares |
| 8/12 | 23.8 squares |
| 10/12 | 25.8 squares |
| 12/12 | 28 squares |
What else matters here
Eighteen hundred square feet of footprint at 6/12 is 2,012 square feet of roof, 22.1 squares with waste, sixty seven bundles.
The list calls for three rolls of synthetic underlayment at ten squares each, and synthetic is worth the small extra over felt on a roof this size. It weighs a fraction as much, does not tear when someone walks on it, lies flat rather than wrinkling in the sun, and stays watertight for weeks if the job is interrupted by weather.
Felt is still permitted everywhere and is still the cheaper line on a bid, and it is a false economy on anything bigger than a shed. What underlayment is not, in either material, is a substitute for flashing or for the ice and water membrane in valleys and at eaves. It is the second line of defense for water that gets past the shingles, which happens more often than people think, particularly in wind driven rain.
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 1,800 sq ft house?
About 67 bundles at a 6/12 pitch with ten percent waste, which is 22.1 squares.
Is synthetic underlayment better than felt?
On anything larger than a shed, yes. It is lighter, does not tear underfoot, lies flat, and stays watertight far longer if the roof is left exposed.
How many rolls of underlayment do I need?
One roll per ten squares for standard synthetic, so a 22 square roof takes three. Check the roll, because coverage varies by product.
The roofing calculator takes any dimensions you like and hands back the same list.