Hip Roof Framing Basics

A plain-language overview of hip roof members and what the geometry here can and cannot tell you.

A hip roof is framed from a few repeating members. Understanding their roles makes the calculator outputs easier to read and keeps you from asking a geometry tool for something only a cutting model and a structural design can provide.

The members

Common rafters run straight up the slope from the wall to the ridge. Hip rafters run diagonally from the corners to the ends of the ridge. Jack rafters are shortened commons that run from the wall to a hip, getting shorter toward the corner. A king common sits at the center of each hipped end, in line with the ridge. The ridge is the horizontal line where the two long faces meet.

Ridge board vs. structural ridge

A ridge board is a non-structural nailing surface that the rafters bear against in a conventional, rafter-tie roof. A structural ridge beam actually carries load and changes how the roof is supported. These are different things with different sizing, and neither is determined by the line geometry on this site.

Line geometry and its limits

The calculators give theoretical line lengths and angles to the horizontal. They do not provide plumb, seat, cheek or backing cuts, physical hip-thickness deductions, member sizes or load capacity. Those come from a verified cutting method and a structural design by a qualified professional. Use the common, hip and jack rafter tools to understand the geometry, then confirm the build details properly.