A parallel chord truss has top and bottom chords running parallel to each other rather than sloping toward a peak, creating a truss with consistent depth along its entire length, commonly used for flat or low-slope roofs and increasingly for floor systems as well.
This consistent depth distinguishes parallel chord trusses from the more familiar sloped roof trusses, making them particularly suited to applications where a level or minimally sloped structure is the design goal.
Because the chords remain parallel rather than converging toward a peak, this truss type can be engineered to achieve quite long spans while maintaining consistent structural depth throughout.
What Does a Parallel Chord Truss Involve?
- Top and bottom chords running parallel throughout the span
- Consistent overall depth along the truss’s length
- Diagonal web members providing triangulated support
- Applications in both flat roofs and floor systems
Why Are Parallel Chord Trusses Important?
The consistent depth of a parallel chord truss makes it well suited to applications requiring a level structural plane, whether a flat commercial roof or a floor system, offering the material efficiency and long-span capability of truss construction without the sloped geometry that a conventional roof truss provides. This versatility has expanded truss use well beyond traditional sloped roof applications into floor framing as well.
Like other truss types, the open web design of a parallel chord truss offers the practical advantage of allowing mechanical systems, ductwork, plumbing, and wiring, to pass through the open spaces within its depth rather than requiring separate chases or dropped ceilings.
Parallel Chord Truss vs. Floor Truss
Parallel chord truss describes the specific chord geometry, running level rather than sloped. Floor truss describes the application, a truss designed for floor loads, and in practice most floor trusses actually use a parallel chord design given the level nature of most floor systems.