K-style vs half-round gutter capacity compare
Typical published planning values — NOT a certified design. Actual gutter sizing depends on local rainfall intensity, roof geometry, valleys and debris; follow local code and the manufacturer’s data, and consult a pro for complex roofs. Structural roof-load, ice-dam / heat-cable and foundation/yard drainage are set by code and a professional — not engineered here.
At the same nominal size, half-round holds less than K-style, so it usually needs to be one size larger for the same roof. The table below shows the labeled max roof drainage area at 6 in/hr by profile and size. Use it with the K-style vs half-round compare and the 5" vs 6" compare.
| Gutter size | Profile | Max roof area at 6 in/hr |
|---|---|---|
| 5" | K-style | 2,500 ft² |
| 6" | K-style | 3,840 ft² |
| 7" | K-style | 5,520 ft² |
| 5" | Half-round | 1,920 ft² |
| 6" | Half-round | 2,500 ft² |
Labeled max roof drainage area at 6 in/hr — half-round holds less than K-style at the same nominal size, so it typically needs one size larger for the same roof. Confirm local rainfall and code.