Apex: Same as Peak
Bearing: A structural support, usually a beam or wall that is designed by the building designer to carry the truss reaction loads to the foundation.
Birdsmouth Cut: A long notch at the ends of a member to allow for an overhang with an “over the wall height” less than the width of the member.
Blocking: Wood or metal members that are placed between trusses and joists in an angled position intended to spread the loads.
Bobtail: Same as Stub Truss
Bottom Chord: An inclined or horizontal member that establishes the bottom member of a truss. An example of an inclined bottom chord member is the bottom chord of a scissor truss or a truss positioned between supports at different elevations.
Bottom Chord Bearing: Term usually used to describe the bearing condition of a parallel chord truss that bears on its bottom chord.
Bottom Plate: The bottom framing member of a stud wall.
Bridging: Same as Blocking
Butt Cut: Slight vertical cut at outside edge of truss bottom chord to ensure uniform nominal span and tight joints – usually ¼ inch.
Butt Joint: The interface at which the ends of two members meet in a square cut joint.
CAD: Computer aided design and drafting software
Camber: An upward curvature built into a truss bottom chord to compensate for anticipated deflection due to loading conditions.
Cantilever: The part of a truss that extends beyond its support, exclusive of overhang.
Check: A lengthwise separation of wood fibres, usually extending across the rings of annual growth, caused chiefly by strains produced in seasoning.
Chord: The truss members forming the top and bottom edges of the truss.
Clear Span: Generally indicates the inside or interior frame to frame dimensions. Not to be confused with Span
Clinched Nail: A nail selected to be longer than the member it is driven through and which is bent back the dimension of its excess length.
Clipped Truss: Same as Stub Truss
Collar Beam: Wooden member connecting opposite roof rafters.
Collar Tie: A horizontal member placed between two rafters a specific vertical distance above the top plate for the purpose of limiting outward thrust of the rafters.
Composite Lumber: A family of materials that contain wood in whole or fiber form and are bound together with an adhesive of natural or synthetic form.
Compound Cut: A double cut made across the member width.
Concentrated Load: Superimposed load centered at a given point( ie roof mounted AC unit.)
Connector Plate: Pre-punched metal toothed connectors located at the joints and splices of a truss and designed to hold the forces that occur at those locations.
Conventional Framing: Framing with conventional joists rafters and wall studs.
Cottage Roof: Same as Hip Roof
Creep: Deformation of a structural member under constant load over time.
Cricket: A ridge or drainage diverting roof framing. Generally found on the high sloped end of a chimney.
Dead Load: Any permanent load such as the weight of roofing, flooring, sheathing, insulation or ceiling material, as well as the weight of the truss itself.
Deflection: Downward vertical movement of a truss (when in place) due to dead and live loads.
Design Loads: The dead and live loads which a truss is engineered to support.
Distributed Load: Loads spread evenly along truss members.
Fascia: The flat surface located at the outer end of a roof overhang or cantilever end.
Feather Cut: A heel cut which has been made with a zero butt cut.
Gable: The portion of the roof above the eave line of a double sloped roof.
Gable Truss: A component manufactured to the profile of the mating standard truss. It has vertical “in-plane” members fastened to the chords instead of diagonal web members. It is not a structural truss and requires continuous support by a bearing wall or other load bearing element such as a beam along the bottom chord.