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Your Roof and Floor Truss Specialist for Residential and Commercial Builders
Glossary of Terms
CAD - Computer aided design and drafting software.

Camber -  Upward curvature built into a truss bottom chord to compensate for deflection due to loading conditions.

Cambium - Layer of cells that lies between the inner bark and the wood of a tree, that repeatedly subdivides to form new wood and bark cells.

- The condition where top and bottom chords extend beyond a support with no bearing at the extended portion.

Center Bearing Truss -  Truss with structural support at center of truss span as well as at the heel joints.

Center Line Span - Theoretical span sometimes used to design trusses.

Chase Opening - Rectangular opening in a floor or sloping flat truss for the purpose of running utilities through it, such as heating and air conditioning ducts.

Check - Separation of the wood along the fiber direction that usually extends across the rings of annual growth, commonly resulting from stress set up in wood during seasoning.

Clear Span - Horizontal measurement between the inside faces of the bearing supports.

Clinch Nail -  Nail selected to be longer than the member it is driven through and which is bent back the dimension of its excess length.

Clipped End - See Stub Truss.

Collar tie - Horizontal member placed between two rafters a specific vertical distance above the very top plate line for the purpose of limiting outward thrust of the rafters.

Combined Stress - Combination of axial and bending stresses acting on a member simultaneously, such as occurs in the top chord (compression + bending) or bottom chord (tension + bending) of a truss.

Combined Stress Index (CSI)  - Summation of axial and bending stressors divided by their respective allowable stresses for a specific truss member.  This ratio, or index, represents the structural "efficiency" of the member.  The CSI shall not exceed 1.00.

Composite Lumber (Structural, Wood Composites) -  Family of materials that contain wood in whole or fiber form bound together with an adhesive of natural or synthetic form.

Compound Cut - Double cut made across the member width.

Compression Chord - Chord members in a truss that resist compression (push) forces.

Concentrated Load - Loading applied at a specific point, such as a load-bearing wall running perpendicular to a truss, or a roof-mounted A/C unit hanging from a truss.

Continuous Lateral Bracing - See Lateral Bracing

Conventional Framing (Common Framing) - Framing with conventional joists, rafters and wall studs.

Creep - Time-dependant deformation of a structural member under constant load.

Cricket - Drainage-diverting roof framing.  Generally found on the high sloped end of a chimney.

Cripple Rafter - Infill rafter installed to continue the roof line - fixed to valley board in valley construction.

Crook - Distortion of a piece of lumber in which there is a deviation in a direction perpendicular to the edge from a straight line from end to end in a piece.

Cross Bracing - Bracing installed in the web member plane of trusses to transfer lateral loads out of the truss system and up into the roof and down into the ceiling diaphragms.

Cross Bridging - Wood or metal members that are placed between trusses or joists in an angled position intended to spread the load.

Cup - Distortion of a board on which there is a deviation flat-wise from a straight line across the width of the board.

Cutting Sheets - (Cut Sheets) Diagram of lumber lengths and angles of cut for truss web members and chords
R & R Components, Inc.
5180 Commerce Drive
York,  PA   17404
Telephone: (717) 792-4641
Toll Free: 1-800-233-9423
Fax: (717) 792-2678
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Copyright 2002  R & R Components, Inc.