Roof Rafter Terminology

When repairing or replacing a roof it pays to be familiar with these terms.

Roof rafter terminology.

Definition of valley rafter or cripple jack rafter. Here is a closer look at common roofing terms. Tlor total length of rafter this is the total length from center of ridge to the facial cut. Being smaller than a principal rafter.

Ll line length also called lor. In the sketch above the valley rafter is drawn in yellow. Roof live load see snow or non snow. Application of calculations rafter lengths calculated mathematically.

Eave span length the horizontal length i e. Includes illustrations that show roofs have hip rafters ridge boards jack rafters and more. Length in plan of the rafter from a structural beam or wall to another structural beam or wall. Roof dead load the approximate weight of roofing materials.

Common rafter minor rafter. Rafters are inclined members spaced from 16 to 48 inches apart. They do for the roof what the joists do for the floor and what the studs do for the wall. They vary in size depending on their length and spacing.

Ridge the horizontal line at the top of a pitched roof applies whether there is a sloping roof on both sides a duo ridge or if there is just one a mono ridge. Principal rafter major rafter rarely a chief rafter. A principal common rafter roof or double roof. A rafter extending from the roof ridge down to the top plate of a wall at the intersection of a gable extension roof that itself abuts or intersects with the main roof.

A bearing timber forming part of a suspended timber floor to which the floor boards are nailed to the top and a ceiling may be attached beneath or. Common rafter terminology. Definitions of rafter span run roof span slope collar ties. Length in plan of the overhang portion of the rafter.

In most cases in this manual tails are added later. Auxiliary cushon compound. A term used to describe a pitched roof the ends of which are also sloped. Lor length of rafter this is the mathematical length from the center of the ridge to the outside of the wall.

Rafter the members making up the main body of the framework of all roofs are called rafters. The tops of the. Usually land directly on a tie beam. These are short spars that run from a hip to the eves or from a ridge to a valley.

Bct 122 roof framing 1 rafter terminology calculations. Rafters on opposite sides of the ridge should be installed directly opposite each other in pairs although if you see a few that don t align it s really not a defect. Rafters which rest on the outside walls at the bottom and connect to the ridge at the top are called common rafters highlighted here in yellow. Hip rafter horizontal run 16 97 valley rafter ridge intersect.