Construction of a Hip Roof

Basic Hip Roof Types

• Two types of hip roof design will be found in basic home construction. These types are the rectangular hip roof and the square, or pyramid, hip roof. Each type has four planes that meet at the center, or ridge, of the home. A rectangular hip roof is supported by the walls and corners of the structure, as well as at the ridge beam at the top. A square hip roof, because of its pyramid shape, is supported by the walls and corners as well as the point at which the tips of the four triangular planes meet at the top.

Hip Roof Variations

• Variations in hip roof design are necessary at times, depending on the overall design of the house. Cross hip roof designs are used to include features that do not fall within the square or rectangular footprint, such as additional rooms and wings of the house. Dutch gable roofs incorporate a hip roof with an added top portion that extends the headroom at the ridge, offering more storage and attic space.

Basic Hip Roof Construction

• The construction of a basic hip roof consists of a series of rafters, beams and trusses that support and transfer the weight of the roof. A basic hip roof contains common rafters, hip rafters and hip jack rafters. Common rafters are located in the middle of a roof plane, hip rafters are at the sides of the triangles of each roof plane and hip jack rafters are placed between the common rafters and the hip rafters. A combination hip roof design with additional roof surfaces also includes valley rafters where two roof planes meet, cripple jack rafters that connect the added roof plane to the hip valley rafter and ridgeboard, and an additional intersecting ridgeboard for the added roof plane.

Hip Roof Calculations

• Many calculations must be made to construct a hip roof. In general, a 45-degree angle exists between the common and hip rafters. The points where rafters meet the wall plates, called a birdsmouth, and meet the ridgeboard, known as working points, must be measured to account for the rise or slope of a rafter and the run or span of the rafter so that cuts can be made at these working points. Many of these crucial measurements can be made using a framing square, an invaluable measuring tool used by many roof construction contractors.