SiC BLAST – Five-Foot Tall Wood Trusses

Five-foot tall Wood trusses now require special inspections

Five-foot tall trusses requiring permanent bracing now require a periodic special inspection to verify that the required bracing has been installed. For wood trusses with a clear span of 60 feet or greater, the special inspector shall verify during construction, that the temporary restraint-bracing is installed in accordance with the approved truss submittal package.

The truss designer determines if and where an individual member of a truss needs to be braced to prevent out-of-plane buckling (roll over) when subjected to design loads. This is what is called permanent individual truss member restraint bracing. If the bracing is not installed at all, or is not installed correctly, it can become a life safety issue.

During the last code cycle, failure of trusses in a number of jurisdictions brought this issue to code hearings. Existing buildings had been inspected after failures and it was discovered that the truss systems often had missing or incorrectly installed bracing.

Engineers believed the inspection requirements of the 2015 IBC were insufficient. A provision has been added to IBC 2018, section 1705.5.2 to require periodic inspection anytime permanent bracing is required and the wood trusses are at least five feet tall. This change now requires most trusses with permanent bracing to have periodic special inspections.

This permanent truss bracing is often described as “truss restraint”. It is important to note that the CODE does not require special inspections when temporary bracing alone is required.

Section 1705.5.2 Metal-plate-connected wood trusses. Special inspections of wood trusses with overall heights of 60 inches or greater shall be performed to verify that the installation of the permanent individual truss member restraint bracing has been installed in accordance with the approved truss submittal package.