Module 7, Level 1: Roof Components Review

This module, titled Module 7, Level 1, provides an exhaustive identification of structural members and geometric principles involved in roof framing.

Common Rafter (Label 10 / A): The primary structural framing member that extends from the ridgeboard to the top plate of the wall. It defines the basic slope of the roof.
Hip Rafter: A rafter that forms the junction at an outside corner where two roof planes meet. It runs diagonally from the ridge down to the corner of the wall plate.
Valley Rafter: A rafter that forms the internal intersection where two roof planes meet to create a trough. This allows water to flow toward the eaves.
Hip Jack Rafter (Label 3 / B): A specialized rafter that runs between the top plate of a wall and a hip rafter. These are shorter than common rafters.
Valley Jack Rafter (Label 6): A rafter spanning from a ridgeboard to a valley rafter.
Barge Rafter (Label 12): Also known as a fly rafter, this is the outermost rafter placed at the gable end of a roof. It is often supported by lookouts and forms the roof's lateral overhang.

Main Ridgeboard: The horizontal timber or board located at the apex of the roof. It serves as the central connecting point for the upper ends of the rafters.
Projection Ridgeboard: The extension of the main ridgeboard beyond the gable end wall, providing structural support for the roof overhang.
Collar Tie (Label 2): A horizontal framing member that connects two opposing rafters in the upper half of their length. Its primary function is to prevent the rafters from spreading or sagging under load.
Gable Stud (Label 13): Vertical framing members used in the gable end of a building to support the roof area above the wall line.
Double Top Plate (Label 7): The pair of horizontal members at the top of a wall frame which supports the rafters or the roof structure.
Lookouts: Horizontal members that extend from the last common rafter out to the barge rafter, providing support for the overhang at the gable ends.
Rafter Tail: The portion of a rafter that extends past the exterior wall (double top plate), forming the overhang or eaves of the building.
Post: A vertical structural column used to support horizontal beams or ridges within the roof's internal structure.

Run: The horizontal distance measured from the outside edge of the wall to a point directly below the center of the ridgeboard.
Rise: The vertical distance measured from the top of the wall plate to the top of the ridgeboard.
DIAG (Diagonal): The hypotenuse of the triangle formed by the rise and the run, representing the actual length of the rafter slope.
Comb: Refers to the highest point or the ridge line of the roof.

Label 2: Collar Tie
Label 3 / B: Hip Jack Rafter
Label 6: Valley Jack Rafter
Label 7: Double Top Plate
Label 10 / A: Common Rafter
Label 12: Barge Rafter
Label 13: Gable Stud
VUARY: A designated region in the diagram representing the Valley section of the roof system.
HIP: A designated region in the diagram representing the Hip section of the roof system.
Labels C and D: Supplementary reference points for specific roof intersections in the diagnostic diagram.