A parallel chord or flat truss is so named for its parallel top and bottom chords and is often used to construct floors. There are many roof truss types and variations, including Arch Frame, Belgian, Dropped Chord, Gambrel, Hip Step-down, Howe, Parallel Chord, Pratt Bottom Chord, Pratt Top Chord, Raised Heel, Scissor, Semi Howe, Slope Frame and Warren.
The Quadrangular Truss The truss shown by Fig. 83 is known as a quadrangular truss, although the more common shape for this truss is that shown by Fig. 87. This truss may be considered as two trussed rafters, held in place by the tie T at the centre.