Two of the strongest types of prefabricated roof trusses are the tri-bearing and hip designs. Both of these designs utilize the triangle's inherent structural strength and distribute the roof's load evenly among their constituent parts. However, such strong trusses are only required for very large construction projects.
A tri-bearing prefabricated roof truss is simply a development of the king post roof truss, the most common type of truss system in residential applications. In a king post truss, the vertical king post supports the vertex of the angle formed by the sloping top chords. This is a very simple but reasonably strong design.
In a tri-bearing truss, two smaller king post-style trusses support a large, central diamond that has its own king post providing further support to the entire roof. Essentially three king post trusses connected together, the tri-bearing truss design is extremely strong, and it is suitable for the largest wood-framed construction projects. A clerestory roof is a variant of the tri-bearing truss that extends one top chord slightly over the other, creating a space for windows or additional ventilation.
A hip roof truss is distinct from a traditional rafter-and-purlin hip roof. A hip roof truss is similar to a tri-bearing truss, but instead of a central diamond, it features an inverted king post truss. The inverted king post creates a flat area on top of the roof.