Roof Truss Lateral Bracing

When truss spacing exceeds 2 feet purlins are generally required to support roof sheathing.

Roof truss lateral bracing.

The stabilizer must be supplemented with diagonal bracing in the roof and ceiling planes and cross bracing in the web plane at required intervals shown on the individual truss design drawing tdd. Roof sheathing plywood osb provides effective lateral bracing when sheathing is nailed directly to top chords. Certain truss members require bracing in order to carry the full design load. Hold these restraints in place with two nails each.

To strengthen the roof system truss clustering cross bracing and wind bracing is recommended at both end of the buildings and every 20 for longer span buildings. Diagonal braces are required at each end of a truss row and repeated every 10 truss spaces 20 maximum. Diagonal bracing installed for the purpose of increasing the stability of the truss system during installation shall be installed on web members verticals whenever possible located at or near each row of bottom chord lateral restraints. Set each truss after the first with its top chord temporary lateral restraint aligned with the ground bracing.

Individual truss member lateral restraint and diagonal bracing the truss designer identifies the location of required individual truss member i e web top chord or bottom chord restraint bracing. There are two separate types of bracing to be concerned about. Purlins 24 oc are typical along with the bottom bracing shown. If trusses are not designed with stabilizer see bcsi 1 for stabilizer spacing and diagonal cross bracing required.

Type of load important. For the purposes of this chapter the guidance and use of standard trussed rafter bracing does not apply to homes on or near exposed sites e g. 7 2 9 bracing for trussed rafter roofs trussed rafters shall be suitably braced to support applied loads and self weight without undue movement. This condition generally applies when trusses are spaced at 2 feet.

Use wooden 2x4 or prefabricated metal braces as short member temporary lateral restraints between the trusses. Flat coastal fringes fens airfields and moorland.