12/12 roof pitch
A 12/12 roof rises 12 inches for every 12 inches it runs: an angle of 45.0°, and a very steep roof. You see it on A-frames, steep gables, turrets and steep Tudor roofs. At 45°, the rise equals the run.
- Angle
- 45.00°
- Slope
- 100.0%
- Area multiplier
- ×1.414
- Rafter per foot of run
- 16.97"
What 12/12 means for your roof
Size. A roof is bigger than the ground it covers. At 12/12 every square foot of footprint carries 1.414 sq ft of roof, so a 2,000 sq ft house has about 2,828 sq ft (28.3 squares) of roofing before overhangs and waste. A quote measured on the footprint alone under-buys every shingle and every hour of labour by 41.4%.
Working on it. Treated like a wall. Everything is staged and roped, waste on cuts is higher, and quotes carry the largest steep-roof premiums. Federal safety rules (OSHA 1926.500) treat any roof above 4/12 as a steep roof.
Cost. Replacing architectural shingles on that 2,000 sq ft house, old layer torn off, comes to about $15,500–$17,900 at US-average roofer wages. That figure follows the roof's area only: the steep-roof labour charge most roofers add at this pitch comes on top. Price your own roof from satellite.
Roofing materials at 12/12
Minimum slopes in the International Residential Code (2021). Cities adopt it with changes, and a manufacturer's instructions can be stricter, so check locally before you buy.
- Asphalt shingles — allowed (minimum 2/12, IRC R905.2.2)
- Clay or concrete tile — allowed (minimum 2½/12, IRC R905.3.2)
- Metal shingles — allowed (minimum 3/12, IRC R905.4.2)
- Slate — allowed (minimum 4/12, IRC R905.6.2)
- Standing-seam metal panels — allowed (minimum ¼/12, IRC R905.10.2)
12/12 pitch questions
What is a 12/12 roof pitch in degrees?
45.00 degrees. The angle is arctan(12 ÷ 12). As a percent slope it is 100.0%.
How much bigger is a 12/12 roof than the house's footprint?
Multiply the footprint by 1.414. A 2,000 sq ft footprint has about 2,828 sq ft of roof at 12/12, before overhangs and waste.
Can you put shingles on a 12/12 roof?
Yes. 12/12 is within normal shingle installation; the model building code allows asphalt shingles from 2/12 up.
Is a 12/12 roof walkable?
Treated like a wall. Everything is staged and roped, waste on cuts is higher, and quotes carry the largest steep-roof premiums.
Need a price for your roof?
Type your address: we trace your roof from satellite, apply its pitch, and show what a replacement costs. Free, about a minute.
Get my roof priceRoofer? Your customers can do the same on your website — see the quote widget.