Roof pitch, also called roof slope, is how steep a roof is. It is written as the number of inches the roof rises for every 12 inches it runs horizontally, so a "6/12" roof rises 6 inches for each 12 inches of run. A higher first number means a steeper roof.
How do you read a pitch like 6/12?
Picture a level line that goes 12 inches out from the wall. Now picture the roof climbing up from the end of that line. If the roof climbs 6 inches, the pitch is 6 in 12, usually written 6/12 and spoken "six-twelve" or "a six pitch."
| Pitch | How it looks | What it generally means |
|---|---|---|
| Low (small first number) | Shallow, nearly flat to the eye | Water drains slowly |
| Moderate | The common shape on many houses | Water sheds at a steady rate |
| Steep (large first number) | Visibly tall, harder to work on | Water sheds quickly, but the roof is harder and slower to install |
Roofers use "pitch" and "slope" interchangeably in everyday talk. Strictly, pitch can mean a fraction of the span and slope means the rise-over-run ratio, but most people on a job mean the 12-inch version.
Why does roof pitch matter?
Pitch changes how a roof handles water, wind and installation.
- Water drainage. Our owner, Jeremy Hays, describes slope as how vertical a roof is, and in a way how well it sheds water. A steeper roof sends water off quickly. A shallow roof lets it linger.
- Material choice. Shingles rely on gravity to move water off. Every manufacturer sets minimum slopes, and shingles on shallower roofs need special installation steps or a different roof system entirely.
- Leaks. Jeremy has said that, in his experience, shingles on roofs below a certain pitch will leak, so his crews move to flat-roof options. See our guide to low-slope roofs and underlayment for the full reasoning and our crews' practice, which is not a universal rule.
- Safety and labor. Steep roofs need extra safety gear and often take more time, which can affect scheduling and cost.
- Appearance. Pitch shapes how visible the roof is from the street, which is part of why color and style choices matter more on steeper roofs.
How can I estimate my roof's pitch safely?
You never need to be on the roof to estimate its pitch. These are ground-level and attic approaches, from simplest to most precise:
- Compare with a known pitch. Search for a pitch chart that shows silhouettes of several roof slopes and compare it to the side of your house.
- Use a gable-end photo. Stand back from the end wall of the house where the roof forms a triangle. Take a straight-on photo and use a phone level or pitch-measuring app to read the angle of the roof edge. Treat it as an estimate.
- Measure in the attic, if access is easy and safe. Hold a level horizontally against the underside of a rafter, mark 12 inches along the level, and measure straight up from that mark to the rafter. That height in inches is your rise per 12. Stay on solid framing and never step between joists onto drywall. If the attic is not easy and safe to reach, skip this step.
- Check your plans or home inspection report. They may list the pitch.
- Ask your roofer. Roofers measure pitch every day, and it should be part of any inspection or estimate.
Do not climb onto the roof or lean a ladder against the edge just to measure a slope. A phone photo and a roofer's visit are safer.
What is the difference between low-slope and steep-slope roofs?
The line between a steep-slope roof and a low-slope roof is not the same everywhere. Many manufacturers publish minimum pitches for their shingles. Below that pitch, a different system, such as a membrane, is usually specified. Our crews have a practice cutoff, explained in the guide linked above, but manufacturer instructions and local code decide what is allowed for any given product.
Does pitch affect the price?
It can. Steeper roofs take more time and safety equipment, and shallow roofs may call for a different material. We do not give price figures on this page because every roof is different, so ask your roofer how pitch affects the estimate for your house.
Frequently asked questions
Is roof pitch the same as roof angle? They describe the same steepness in different units. Pitch uses rise over 12 inches of run, and angle uses degrees.
Is a higher pitch better? It is better at shedding water and snow, but it is harder to work on and install. The right pitch is mostly set by the house design, not by choice at replacement time.
Can I change my roof's pitch? Changing pitch is a structural job and not part of a normal re-roof. It involves framing and often an architect or engineer, plus a permit. Ask your building department.
What pitch can shingles be installed on? It depends on the manufacturer's instructions and local code. Each product lists its own minimum, so look it up in the installation instructions for your shingle.
Why does my roofer keep asking about pitch? Because it drives the materials list, the underlayment plan and the safety plan. It is one of the first things we look at.
Can a low pitch cause a leak even on a new roof? It can if the roof system is wrong for the slope. Low-slope roofs can also leak in ways that are hard to find, which we cover on our page on what a roof leak looks like.
Talk to us about your roof
Total Roof Protection OKC can inspect your roof, measure its pitch and explain what we see. Call 405-415-5841 to schedule an inspection. See our services and our page on underlayment.