Setting Trusses Straight
Making correct truss orientation easy for installers
FIGURE B7-4 from the 2018 Edition of the BCSI Book
Trusses are engineered components that will perform as intended if installed correctly. However, those who are installing trusses are not always adept in deciphering truss layout drawings. Even though the truss installers may not be familiar with the design of the truss, steps can be taken to reduce the potential for trusses to be placed upside down or set backwards. By doing a little bit of extra work at the plant, component manufacturers (CMs) can greatly reduce the potential for components to be installed incorrectly.
Depending on the truss design, there may be small differences in a truss that otherwise appears to be symmetrical. These changes can be different plate sizes or an off-center duct chase that are easily missed by those working in the field. Even if a framer is familiar with trusses, it can be very difficult to differentiate trusses that look almost the same but have minor differences. Determining the orientation of bottom chord bearing trusses can be especially difficult due a less defined truss top.