A two-pitched roof — usually called a gable — has two sloping planes meeting at a horizontal ridge. It is the most common roof shape in U.S. residential construction because it is the simplest to frame, the most efficient with materials, and works at any pitch from a near-flat 2/12 to an aggressive 16/12.
This guide walks through the anatomy of a two-pitched roof, the framing layout, how to pick the right pitch for a new build, and the most common variations.
Anatomy of a two-pitched roof
Both planes meet at a horizontal ridge, which can be either a non-structural ridge board (where rafters bear on the wall plates and just lean against each other at the top) or a structural ridge beam (where rafters hang from the ridge and the beam carries the load).
The two non-roof walls extend up to triangular peaks called gable ends. These walls catch wind and need careful detailing in high-wind regions — many storm-prone areas use hip roofs (no gable ends) instead.
Common rafters run perpendicular from the wall plate up to the ridge. There are no hip or valley rafters in a simple gable. Trusses can replace site-cut rafters for a faster, more uniform install.
Framing options
Stick framing — site-cut rafters, ridge board, and ceiling joists. The traditional method, more flexible for unusual pitches and dormers, slower to install.
Pre-engineered trusses — factory-built triangular assemblies that span wall to wall, no ridge required. Faster to install, more consistent, but rigid (you cannot easily modify the roof later).
Engineered ridge beam — for cathedral ceilings or post-and-beam construction, the ridge is structural and rafters hang from it. Lets you eliminate the ceiling joists and open up the space.
| Method | Speed | Cost | Flexibility | Best for |
|---|---|---|---|---|
| Stick framing (site-cut rafters) | 4-7 days for typical home | Highest labour, lowest material | Best — easy to modify | Custom pitches, dormers, future modifications |
| Pre-engineered trusses | 1-2 days for typical home | Lowest total cost | Rigid — hard to modify | Most production residential; standard plans |
| Engineered ridge beam | 5-8 days for typical home | Highest cost (engineered beam + skilled labour) | Cathedral ceilings; vaulted spaces | Open-plan great rooms; post-and-beam construction |
| Hybrid (trusses + stick-framed sections) | 3-5 days for typical home | Mid-range cost | Moderate flexibility | Homes with vaulted areas + standard areas |
Picking the right pitch
For a basic residential gable, 4/12 to 6/12 covers most situations. Lower if you want a contemporary look; higher if you want more attic or a traditional style.
Climate considerations push pitch up in snow country (6/12 minimum, 8/12+ preferred) and allow it lower in mild dry climates (3/12 is fine).
Material constraints set hard floors: 2/12 for asphalt shingles, 4/12 for wood shake or slate.
Need to run the numbers?Use the free roof pitch calculator on the home page to convert pitch to angle, calculate rafter length, or estimate roof area in any unit.