5/12 Roof Pitch — Gutter Sizing Guide
A 5/12 pitch provides a moderately sloped appearance that is popular on two-story homes, colonial-style construction, and transitional architectural designs. The pitch factor of 1.08 adds 8 percent to the effective area, which starts to become significant for gutter sizing in areas with high rainfall intensity. Water velocity on a 5/12 roof is noticeably faster than on a 4/12, improving the self-cleaning characteristics of both the roof and the gutters. Most standard roofing materials perform well at this pitch, and the increased attic volume provides better ventilation and potential storage or living space.
5/12 Pitch Specifications
Gutter Sizing Grid for 5/12 Pitch
The table below shows the recommended gutter profile for various combinations of roof area and rainfall intensity at the 5/12 pitch. The pitch factor of 1.08 is applied to the horizontal roof area before multiplying by the rainfall intensity. This grid helps you quickly find the recommended gutter size without running a custom calculation. For roof areas or rainfall intensities not shown, use the gutter size calculator for a precise recommendation.
| Roof Area | 1 in/hr | 2 in/hr | 3 in/hr | 4 in/hr |
|---|---|---|---|---|
| 800 sqft | Half-Round 5" | Half-Round 5" | Half-Round 5" | Half-Round 5" |
| 1,200 sqft | Half-Round 5" | Half-Round 5" | Half-Round 5" | K-Style 5" |
| 1,500 sqft | Half-Round 5" | Half-Round 5" | Box 5" | Half-Round 6" |
| 2,000 sqft | Half-Round 5" | Box 5" | Half-Round 6" | K-Style 7" |
| 2,500 sqft | Half-Round 5" | K-Style 5" | K-Style 7" | K-Style 7" |
| 3,000 sqft | Half-Round 5" | Half-Round 6" | K-Style 7" | 7"+ |
| 4,000 sqft | Box 5" | K-Style 7" | 7"+ | 7"+ |
Effective Area Examples at 5/12
The pitch factor of 1.08 means that every square foot of horizontal roof footprint represents 1.08 square feet of actual roof surface draining to the gutters. Here are common home sizes with the effective drainage area calculated at 5/12 pitch:
| Horizontal Area | Effective Area (5/12) | Increase |
|---|---|---|
| 800 sqft | 864 sqft | +64 sqft |
| 1,000 sqft | 1,080 sqft | +80 sqft |
| 1,200 sqft | 1,296 sqft | +96 sqft |
| 1,500 sqft | 1,620 sqft | +120 sqft |
| 2,000 sqft | 2,160 sqft | +160 sqft |
| 2,500 sqft | 2,700 sqft | +200 sqft |
| 3,000 sqft | 3,240 sqft | +240 sqft |
| 4,000 sqft | 4,320 sqft | +320 sqft |
| 5,000 sqft | 5,400 sqft | +400 sqft |
Installation Considerations for 5/12 Roofs
Standard-slope roofs at 5/12 pitch provide a good balance of water drainage speed and gutter catchment. Water arrives at the gutter at a moderate velocity that cleans debris effectively without risking overshooting. Standard 5-inch or 6-inch gutters with hidden hangers spaced at 24 to 36 inches provide reliable performance. Ensure that drip edges extend properly into the gutter to direct water flow, and maintain adequate gutter slope of at least 1/16 inch per foot toward each downspout. In areas with heavy tree coverage, gutter guards significantly reduce maintenance frequency.
Regardless of pitch, proper gutter maintenance is essential for long-term performance. Inspect gutters at least twice per year, checking for proper slope, secure mounting, clear downspouts, and intact seals at joints and corners. After heavy storms, verify that no debris blockages have formed and that all downspouts are flowing freely. Investing in quality gutter guards rated for your specific gutter profile can dramatically reduce maintenance frequency while ensuring that your gutters remain at full capacity during the storms when they are needed most.
All Roof Pitches
Browse gutter sizing guides for other roof pitches. Each pitch page includes sizing grids, effective area calculations, and installation guidance specific to that slope.