Illinois Roofing Practice Exam 2026 – Complete Exam Preparation Guide

The bottom chord in a truss system is indeed a horizontal support member. It serves as the foundational element that helps to maintain the integrity of the truss structure. The bottom chord spans between the truss's end supports, effectively distributing the load of the roof or any other elements placed on top.

In a typical roof truss, the bottom chord is held horizontally and works in conjunction with the upper chord and diagonal members to form a triangulated shape, which is crucial for structural stability. This horizontal nature of the bottom chord is what allows it to resist compressive forces and provide a level base for decking or roofing materials, ensuring a stable and safe construction.

Other types of construction members, such as diagonal or vertical supports, have different functions and are oriented differently within the truss system. Diagonal members help to resist shear forces, while vertical members typically carry loads directly downward. Decorative framing members, on the other hand, do not serve a structural purpose and are primarily aesthetic.