Roof Shapes and Terminology

Gable Roof

• The term "gable" refers to a flat wall that caps the end of sloped roof surfaces and extends to the roof's peak. Traditional gable roof structures consist of four exterior walls, two sloped roof surfaces and two gable ends. Structures with gable roofs generally are square or rectangular. Framing gable roofs is relatively uncomplicated: Triangular trusses or rafters span between opposing walls. Gable roofs accept all types of roof-covering materials, including shingles, panels, rolled roofing and tiles.

Hip Roof

• Whereas a gable roof slopes toward two exterior walls, a hip roof slopes toward all exterior walls. A hip roof on top of a square or rectangular structure consists of four sloped surfaces. The sloping ridge where adjacent hip roof surfaces meet is called a hip. A common variation of the hip roof, called a hip and valley roof, covers L-shaped or multi-winged structures. The term "valley" refers to a concave intersection between adjacent roofing surfaces. Hip roof construction is substantially more difficult than gable roof construction.

Shed Roof

• A shed roof's single surface slopes between opposing walls and is among the simplest types of roofs. Building gable and hip roofs requires complex cuts, ridge boards or truss installation, but framing shed roofs often requires only a few cuts and basic materials. A shed roof leaves one or more exterior walls exposed to wind and sun.

Flat Roof

• Flat roofs slope toward drainage gutters or eave lines, and appear horizontally level from a distance. Like shed roof framing, flat roof framing is relatively simple; most flat roof constructions consist of integral planks or joists that span between opposite walls. Flat roofs typically accept only built-up membrane coverings, such as hot-mop asphalt or flexible, synthetic coatings.

Roofing Terms

• Roofing terminology describes architectural features and roof construction materials. The roofing term "pitch" often confuses homeowners. Pitch refers to the degree of a roof's slope. Builders describe pitch in inches per foot. For example, a pitch of 4 in 12 refers to a rise of 4 inches per every run of 12 inches. Other terms include "sheathing," "decking" and "underlayment," which all refer to the same construction component. Sheathing, decking and underlayment materials typically are sheet goods such as plywood that cover a roof's framing and provide a substrate for roof-covering installation.