Apex
The highest point on a truss.
Attic Truss
A truss with an attic room space within the truss. The bottom chord doubles as the floor joist and the top chord as the rafter.
Batten
Roofing battens or ceiling battens. Usually timber members fixed at the truss chords to support roof tiles or ceiling material. Also provides lateral restraint to the truss.
Bearing / Support Point
Point at which the truss is supported. A truss must have two or more supports located at truss panel points.
Bottom Chord
Truss member forming bottom edge of truss.
Butt Joint Splice
End-to-end joint between two pieces of timber.
Cantilever
That part of a truss that projects beyond an external main support, not including top chord extensions or overhangs.
Chord
The truss members forming the top and bottom edges of the truss.
Concentrated Load
A load applied at a specific position. e.g. load applied by an intersecting truss.
Connector
Light gauge steel plates with teeth projecting form one face. When pressed into intersecting timber members the plate connects the members in a rigid joint.
Creep
Movement resulting from long-term application of load to a timber member.
Dead Load
Permanent loads due to the weight of materials and truss self-weight.
Deflection
Movement in a truss due to the applied loads.
Design Loads
The various loads that a truss is designed to support.
Distributed Load
Loads spread evenly along truss member.
Fascia
Trim along the edge of the eaves.
Gable Truss
Standard triangular shaped truss.
Girder Truss
Truss designed to support one or more trusses.
Heel Joint
The joint on a truss where the top and bottom chords meet.
Heel Point
The position on a truss where the bottom edge of the bottom chord meets the top chord.
Hip
Intersection of two roof surfaces over an external corner of a building.
Hip Roof
Roof constructed with rafters or trusses pitched over all perimeter walls.
Jack Truss
Half truss and part of family of trusses that makes a hipset.
King Post
Vertical web at the centre of a gable truss, or the vertical web at the end of a half gable truss.
Lateral Brace
Bracing restraint applied at right angles to web or chord to prevent buckling.
Longitudinal Tie
Bracing restraint applied at right angles to web or chord to prevent buckling.
Live Load
Load as a result of occupancy or use of the building.
Overhang
Extension of top chord beyond support. Provision of eaves on gable trusses.
Panel-point
The point where several truss members meet to form a joint.
Panel-point Splice
Splice joint in a chord coinciding with web intersection.
Pitch
Angular slope of truss chord measured in degrees.
Purlin
Roofing purlins. Usually timber members fixed at right angles to the truss chords to support roof sheeting. Also provides lateral restraint to truss. Similar to battens except more widely spaced.
Rafter
A roof member supporting roofing battens or roofing purlins in conventional construction. Rafters employ only the bending strength of the timber. A roof truss may also be called a trussed rafter.
Ridge
The highest point on a gable roof.
Setback
The position of a truss measured from the outside face of the end wall. Usually used to describe the position of Truncated Girder and Standard trusses in a Hip End.
Span
The horizontal distance between the outer edges of the truss supports.
Span Carried
The span of standard trusses that are supported by a girder truss.
Stop End
Description of a truss based on standard shape but which is cut-off short of its full span.
Top Chord
Truss member forming top edge of truss.
Truss
A framework of members forming a light, strong, rigid structure. Usually a triangulated structure.
Valley
Intersection of two roof surfaces over an internal corner of a building.
Valley Truss or Saddle Truss
Part of a set of non-structural trusses to form valleys.
Web
The internal members of a truss. Usually only subject to axial loads due to truss action.
Wind Load
Load applied to the roof by the wind.