Trusses are engineered wood products used for structural support in roof structures of single- and multi-family residential and non-residential construction. Each truss is a frame composed of shorter lengths of lumber, which can be custom-designed for a particular end use. Light-frame trusses have replaced traditional larger solid-wood rafters in roofing structures, reducing the amount of wood needed and getting more from each tree harvested.
Machine stress rated lumber of varying strengths is normally used in the production of trusses, depending on end-use requirements. Within a single truss, several grades of MSR lumber will also be used, depending on the requirement of each piece as calculated according to engineering principles.
The chords and webs are connected by steel connector plates (“truss plates”). In pitched chord trusses, the top chords meet to form the apex of a triangle. In parallel chord trusses, used for flat roofs, the top and bottom chord are arranged in parallel. Complex and intricate shapes specified by building designers can also be produced. The attic space normally found with more traditional roofing designs is often lost with trusses.
Light-frame trusses are relatively cheap, easy to fabricate and simple to erect on site.
- Date modified: