Apex/Peak – The uppermost point of a truss.
Attic truss/room-in-the-roof – A truss which forms the top storey of a dwelling but allows the area to be
habitable by leaving it free of internal WEB members. This will be compensated by larger timber sizes elsewhere.
Bargeboard – Board fitted to conceal roof timbers at GABLE END.
Battens – Small timber members spanning over trusses to support tiles, slates etc.
Bearer – A member designed to distribute loads over a number of trusses.
Bearing – The part of a truss receiving structural support. This is usually a WALLPLATE but can be an internal wall etc.
Binder – A longitudinal member nailed to trusses to restrain and maintain correct spacing.
Birdsmouth – A notch in the underside of a RAFTER to allow a horizontal seating at the point of support (usually used with RAISED TIE TRUSSES).
Blocking – Short timbers fixed between chords to laterally restrain them. They should be at least 70% of the depth of the CHORDS.
Bottom chord/Ceiling Tie – The lowest member of a truss, usually horizontal which carries the ceiling construction, storage loads and water tank.
Bracing – This can be Temporary, Stability or Wind Bracing which are described under these headings.
Building Designer – The person responsible for the structural stability and integrity of the building as a whole.
Cantilever – The part of a structural member of TRUSS which extends beyond its bearing.
Chevron Bracing – Diagonal bracing nailed to the truss in the plane of the specified webs to add stability.
Dead Load – The load produced by the fabric of the building, always long term (see DESIGN LOADS).
Deflection – The deformation caused by the loads
Design Loads – The loads for which the unit is designed. These consider the duration of the loads long term, medium term, short term and very short term.