Hip Roof, Hip-roof, or Hipped Roof

A roof with the ends inclined, as well as the sides. All four sides slope down to the eaves from the ridge; the outside angles created where two sides of the sloped roof deck meet are called hips, while the inverse of this joining are called valleys.

All sides slope downwards to the walls, usually with a fairly gentle slope. A hipped roof house has no gables or other vertical sides to the roof, unless there is a combination of designs used in a single structure.

A square hip-roof is shaped like a pyramid. Hip roofs on houses could have two triangular sides and two trapezoidal ones. A hip roof on a rectangular plan has four faces. They are almost always at the same pitch or slope, which makes them symmetrical about the centerlines.

Hip roofs often have a consistent level fascia, meaning that a gutter can be fitted all around. An advantage of this type of roof structure is the protective overhang formed over end walls as well as over side walls, and the eaves are carried on the same plane generally, allowing for more control of roof drainage.

The hip roof is self-bracing, requiring less diagonal bracing than a gable roof. Hipped roofs are thus much better suited for hurricane regions than gable roofs. Hip roofs have no large, flat, or slab-sided ends to catch wind and are inherently much more stable than gable roofs.

However, for a hurricane region, the roof also has to be steep-sloped; at least 35 degrees from horizontal or steeper in slope is preferred. When wind flows over a shallow sloped hip roof, the roof can behave like an airplane wing. Lift is then created on the leeward side. The flatter the roof, the more likely this will happen. A steeper pitched hip roof tends to cause the wind to stall as it goes over the roof, breaking up the effect. If the roof slopes are less than 35 degrees from horizontal, the roof will be subject to uplift. Greater than 35 degrees, and not only does wind blowing over it encounter a stalling effect, but the roof is actually held down on the wall plate by the wind pressure.

A possible disadvantage of a hip roof, compared with a gable roof on the same plan, is that there is less room inside the roof space; access is more difficult for maintenance; hip roofs are harder to ventilate; and there are no gables with windows for natural light.

While the design is rather dated, it does allows for "Ranch Style" sprawling, roomy floorplans that provide less exterior wind resistance and vacuum than a gable roof. The truss systems in hip roof designs can be quite complicated and costly to build, but provide a very sturdy, weather conductive roof surface.