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Glossary of Terms used in Trussed Rafter Construction
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 a GABLE END.
 
Battens
Small timber members spanning over trusses to support tiles, slates etc.
 
Bearer
Amember designed to distribute loads over a number of trusses.
 
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.
 
Bobtail
Atruss type formed by truncating a normal triangular truss.

 
Bottom Chord
See CEILING TIE.
 
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.
 
Camber
An upward vertical displacement built into a truss in order to compensate for deflection which might be caused by the loadings.
 
Cantilever
The part of a structural member of a TRUSS which extends beyond its bearing.
 
Ceiling Tie
The lowest member of a truss, usually horizontal which carries the ceiling construction, storage loads and water tank.
Chevron Bracing
Diagonal web bracing nailed to the truss in the plane of the specified webs to add stability.
 
Connector Plate/fastener
See NAILPLATE.
 
Cripple Rafter
See JACK RAFTER.
 
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 cnsider the duration of the loads long term, medium term, short term and very short term.
 
Duo/dual Pitch Truss
A truss with two rafters meeting at the APEX but not necessarily having the same PITCH on both sides.
 
Dwangs
See NOGGINGS.
 
Eaves
The line between the rafter and support wall.
 
Eaves Joint
The part of the truss where the rafter and the ceiling tie intersect. This is usually where the truss is supported.
 
Extended Rafter
See RAISED TIE TRUSS
 
Fascia
Horizontal board fitted around the perimeter of the building to the edge of the truss overhangs.
 
Fastener
See NAILPLATE.
 
Fink Truss
The most common type of truss used for dwellings.  It is duo-pitch, the rafter having the same pitch. The webs form a letter W.
 
Firring Piece
A tapered timber member used to give a fall to flat roof areas.
 
French Heel
An EAVES joint where the rafter sits on the ceiling tie.
 
Gable End
The end wall which is parallel to the trusses and which extends upwards vertically to the rafters.