Ways to Construct a Hip Roof

Characteristics of a Hip Roof

• A hip roof, unlike a gable roof that slopes only on two sides, slopes up from all four exterior walls of a rectangular building to meet at a central ridge at the highest point. A hip roof is framed with long rafters, called common rafters, on two sides. One end of a common rafter rests on the top of an exterior wall, while the other rests against the ridge beam, a horizontal framing member that runs along the peak of the roof. In a gable roof, the ridge beam runs all the way from one end of the building to the other, but in a hip roof, the ridge beam stops short of the building ends. A long diagonal rafter, called a hip rafter, slopes from the end of the ridge beam to the top of the exterior walls at the corner of the building, forming the point where the perpendicular slopes of the roof meet. Shorter rafters, called hip jacks, have one of their ends resting on top of the walls and the other end resting against a hip rafter.

Dutch Hip Roof

• In a Dutch hip roof, the end slopes stop short of the ridge beam, and a triangular gable sits at the top of the end slope. In this type of hip roof framing, the ridge beam ends closer to the ends of the building, resulting in more interior space under the peak of the roof.

Cross Hip Roof

• Perpendicular hip roofs intersect to make a cross hip roof. Each independent hip roof section is framed the same way as a conventional hip roof, and the point of intersection is framed with a long rafter called a valley rafter. It sits with its upper end at the point where the ridge beams intersect, and its lower end rests on the top of the walls at the corner where the perpendicular walls intersect. Short rafters with one end on the valley rafter and the other on the top of the wall are called valley jacks.

Roof Trusses

• Hip roofs may be framed with engineered roof trusses instead of individual framing members. Truss framing follows the same geometric plan as conventional framing, except that the ends of the ridge beam are supported by a specially engineered truss called a girder truss that is better able to bear the weight of the ridge end. Hip jack trusses then extend from the building end to the girder truss. Variations of this design use "step down" trusses of decreasing height to form the slope of the hip, and the girder truss that supports the ends of the hip jacks is moved to a position between the end of the ridge and the exterior wall.