Hip Rafter & Ridge Board Calculator

Understanding Hip Roof Geometry

A hip roof has four sloping sides — two triangular gable ends replaced by additional sloping panels. The ridge board runs along the top center, shorter than the building by the full hip setback on each end. Four hip rafters run diagonally from each corner to the ends of the ridge. Between hip rafters, jack rafters fill in the slope.

Why Hip Roofs Are Common in Kentucky

Hip roofs perform better in high-wind conditions than gable roofs because all four sides are braced against the structure. They're also more resistant to roof lift from the suction effect of high winds — a meaningful consideration in Grayson County where severe weather and tornado threats are a reality. UIR's metal roofing installations on hip roofs use specialized hip cap trim pieces that seal the corner intersections weather-tight.

The Rafter Square Approach

On site, hip rafter layout uses a framing square with the rafter square tables. The hip rafter unit run is 16.97 inches (the diagonal of a 12×12 square) rather than 12 inches for common rafters. For a 5/12 pitch, the hip rafter unit length is 18.03 inches per foot of run. The cheek cuts (compound angles) at both the ridge and the hip corner require a two-plane cut that a framing square helps mark. For complex roof framing in residential projects or new home construction in Grayson County, contact UIR.