Rafters:  the wooden structural support beams for a roof, sometimes visible on the exterior for certain building types and styles.

  • A rafter is one of a series of sloped structural members (beams) that extend from the ridge or hip to the wall-plate, downslope perimeter or eave, and that are designed to support the roof deck and its associated loads.
  • Not to be confused with:
    • a person who engages in the sport or pastime of rafting.
    • a flock, especially of turkeys.

Valley:  A valley is point in a roof where rafters of different angles come together.

Valley Rafter: a rafter that is attached to the ridge at the top and the valley at the bottom.

  • A part of the roof frame that extends diagonally from an inside corner plate to the ridge board at the intersection of two roof surfaces.
  • In a roof framing system, the rafter in the line of the Valley; connects the ridge to the wall plate along the meeting line of two inclined sides of a roof which are perpendicular to each other.

Truncated: cut off or cut short, usually in reference to a roof.

  • To shorten by cutting off a part; cut short.
  • A gable roof or hipped roof whose top has been cut off, forming a flat horizontal surface.

Truss:  A structural framework of wood or metal, esp one arranged in triangles, used to support a roof, bridge, etc.

  • Any of various structural frames constructed on principles other than the geometric rigidity of the triangle or deriving stability from other factors, as the rigidity of joints, the abutment of masonry, or the stiffness of beams.
  • In architecture and structural engineering, a truss is a structure comprising one or more triangular units constructed with straight members whose ends are connected at joints referred to as nodes. External forces and reactions to those forces are considered to act only at the nodes and result in forces in the members which are either tensile or compressive forces. Moments (torques) are explicitly excluded because, and only because, all the joints in a truss are treated as revolutes.

Truss Plan: A truss plan will show every truss that will make up a roof system. Each truss will be numbered and will be shown on shop drawing with dimensions and specifications.

Revolute Joint (also called pin joint or hinge joint):  is a one degree of freedom kinematic pair used in mechanisms.  Revolute joints provide single-axis rotation function used in many places such as door hinges, folding mechanisms, and other uni-axial rotation devices.