A 6/12 roof pitch rises 6 inches vertically for every 12 inches of horizontal run. That converts to 26.57° from horizontal, a slope of 50%, and a slope factor of 1.118. After 4/12, it is the second-most-common residential pitch in the U.S. and the standard for most traditional architectural styles — colonial, craftsman, contemporary, and most two-story homes built since the 1980s.
This guide covers the 6/12 specifics, why it sits at a sweet spot for many builds, materials and detailing, and how it compares to neighbouring pitches.
6/12 by the numbers
A 6/12 pitch is exactly 26.57° from horizontal. The slope as a percentage is 50% — for every foot of horizontal travel, the roof rises 6 inches. The slope factor of 1.118 means actual roof surface is 11.8% larger than building footprint. For a 1,500 sq ft footprint, a 6/12 gable has roughly 1,677 sq ft of roof surface.
Rafter math at 6/12: rafter length per foot of run is √(6² + 12²) / 12 = 1.118 feet. For a 14-foot run, common rafter length is 15.65 feet plus overhang.
Relative to 4/12, a 6/12 pitch produces 6.4% more roof surface area for the same building footprint, and an attic that is 50% taller (7.5 ft peak height versus 5 ft at 4/12 on a 30-foot wide building).
| Property | 6/12 value | 4/12 comparison | 8/12 comparison |
|---|---|---|---|
| Angle from horizontal | 26.57° | vs 18.43° | vs 33.69° |
| Slope percentage | 50% | vs 33.3% | vs 66.7% |
| Slope factor | 1.118 | vs 1.054 | vs 1.202 |
| Surface area for 1,500 sf footprint | 1,677 sq ft | vs 1,581 sq ft | vs 1,803 sq ft |
| Attic peak height (30 ft wide bldg) | 7.5 ft | vs 5.0 ft | vs 10.0 ft |
| Walkability | Comfortable | Comfortable | Borderline |
| Labour premium | Baseline | Baseline | +10-20% |
| Solar panel suitability | Near-optimal | Slightly low for some latitudes | Slightly steep for some latitudes |
| Snow shedding | Moderate | Slow shedding | Active shedding |
Why 6/12 is a sweet spot
6/12 sits at the convergence of several practical thresholds. It is steep enough to provide meaningful attic volume for storage, future finished-attic conversion, or improved ventilation. It is shallow enough to be comfortably walkable for roofing crews — no fall-arrest harnesses required, no labour premium. It is well above the minimum pitch for every standard roofing material, so there are no underlayment compromises or material restrictions.
Aesthetically, 6/12 produces a defined roof profile that reads as residential rather than commercial-flat. It works for a wide range of architectural styles from contemporary minimalism to traditional colonial. Production builders often offer 6/12 as an upgrade from a base 4/12 spec — typically a $1,000-3,000 upcharge that buys meaningful attic space and stronger curb appeal.
For renovations and additions, matching an existing 6/12 pitch is usually the right call. The pitch is common enough that materials and trim are widely available, and matching pitch keeps the building visually coherent.
Materials at 6/12
Every standard roofing material works without restriction at 6/12. Asphalt shingles install with single-layer underlayment. Metal panels are well within their pitch range. Tile (concrete and clay), slate, and wood shake all comfortably exceed their 4/12 minimums.
Specifically: asphalt three-tab and architectural shingles install per standard residential specs with 25-50 year warranties. Standing-seam metal performs excellently — 6/12 is a near-ideal pitch for the system. Corrugated metal works without extended overlap detail. Concrete and clay tile have full material flexibility. Slate at 6/12 is well within the recommended range (4/12 is the absolute minimum for slate). Wood shake at 6/12 sheds water reliably.
For underlayment, synthetic underlayment plus ice-and-water shield in valleys and at eaves is the modern spec. The pitch itself does not require extended underlayment — the IRC R905.1.1 double-underlayment requirement applies only to pitches under 4/12.
Cost in 2026
For a typical 2,000 sq ft single-story house with simple gable at 6/12: architectural asphalt shingle replacement runs $11,500-19,000 installed in 2026 — a small premium ($500-1,000) over the same project at 4/12 because of the slightly larger surface area. Three-tab runs $8,500-14,000. Standing-seam metal runs $21,000-35,000.
The 6/12 pitch is comfortably walkable, so labour is at the regional baseline. There is no fall-protection premium until 8/12 and above. Material costs scale linearly with the slope factor — 6.4% more material than at 4/12.
Compared to steeper pitches, 6/12 saves 5-10% over 8/12 (which adds modest labour premium) and 15-25% over 12/12 (which adds significant labour premium plus more material).
Attic volume and finished-attic potential
A 6/12 pitch produces meaningful attic volume. On a 30-foot wide building, the attic peak height is 7.5 feet at the ridge and tapers to zero at the eaves. The usable floor area at 6 feet of headroom (the typical minimum for a finished space) is roughly half the building width — about 15 feet of usable width on a 30-foot building.
For finished-attic potential, a 6/12 pitch is the practical minimum. Below 6/12, the usable area at 6+ feet of headroom is too narrow for most usable rooms. At 6/12 you get a usable space that is generous enough for bedrooms or office space; at 8/12 the space becomes substantially larger; at 12/12 the entire attic floor is usable.
For storage-only attics, 6/12 provides ample volume — typically 15-25% of the building footprint as usable floor space at 4+ feet of headroom.
Common 6/12 applications
Two-story colonial and traditional homes — 6/12 is the standard pitch for most colonial-style new construction.
Craftsman and prairie-style homes — works with the broader-eave detailing and exposed rafter aesthetic.
Contemporary homes where roof presence matters but extreme slopes are not desired.
Production homes upgraded from base 4/12 for the curb-appeal and attic-volume premium.
Additions matched to existing 6/12 roofs — by far the most common existing-building condition for renovations built between 1980 and present.
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.