What does a roof pitch and degree chart show, and how do you read it?
Short answer. A roof pitch degree chart lists each pitch, written as inches of rise per 12 inches of run, beside the angle it makes with level ground: 4/12 is about 18.4 degrees, 6/12 about 26.6, 8/12 about 33.7 and 12/12 exactly 45. Most Georgia houses fall somewhere between about 18 and 37 degrees.
The chart, grouped by how a roof behaves
- Low slope, 1/12 to 3/12 (4.8 to 14.0 degrees): porch roofs, patio covers and some additions. Asphalt shingles are not allowed below 2/12, and from 2/12 up to 4/12 the code calls for a double layer of underlayment.
- Walkable, 4/12 to 7/12 (18.4 to 30.3 degrees): most ranch homes and many older subdivisions. A crew can work these without roof jacks on a dry day.
- Steep, 8/12 to 10/12 (33.7 to 39.8 degrees): common on two-story homes built in the last few decades. Expect harnesses, roof jacks and toe boards.
- Very steep, 12/12 and up (45 degrees and up): front gables, Tudor and Victorian styles. Past about 20/12 (59 degrees), the code and shingle makers require special steep slope fastening.
Reading the chart without fooling yourself
- The angle grows slower than the pitch. Doubling 6/12 to 12/12 takes the angle from 26.6 to 45 degrees, not to 53.
- Half pitches are real. A 7.5/12 roof is about 32 degrees, and framers sometimes use them on trusses.
- Degrees from an app are approximate. Round to the nearest whole pitch; a one degree error is roughly a quarter of a pitch on most homes.
Why the angle matters on a quote
Steepness changes three things a homeowner pays for: how much surface the roof has, how much safety equipment and time the crew needs, and whether the roof needs special underlayment or fastening. That is why two houses with the same footprint can get very different prices. See how roofers measure a roof and roof replacement cost in Georgia for how the angle shows up in the numbers.