Types of Roof Trusses

Trusses are triangular structures often used in the construction of residential roofs and bridge systems. By definition, a truss consists of at least five triangular units with straight elements that connect at the nodes, which are the joints of the structures. The design of a truss is highly efficient at distributing weight, creating a strong support system with a relatively low weight. Companies like Hayward Lumber engineer trusses to be as lightweight as possible while bearing the heavy loads. While wood is weaker than metal building materials, trusses take advantage of the strength it by distributing it efficiently. There are several varieties, each one suited for different tasks.

Planar Trusses


Planar trusses are most commonly found in the roofs of homes. This type of truss is essentially one large triangle made up of smaller ones, and this is often what gives the quintessential house its angled roof appearance. You can also find this structure type in aircraft and bikes.

Pratt Trusses


Caleb Pratt, along with his son, Thomas, were two railway engineers in Boston who developed and patented the Pratt truss in the mid 1800s. This design uses more vertical elements than other most other trusses, with horizontal elements used to handle changes in tension. To this day, the Pratt truss is a very popular choice for handling vertical loads.

King and Queen Posts


Of all the truss types, king posts are some of the most basic. They are made up of a single vertical post with one angled support on each side. A variation on this style is the queen post, which has a second vertical post with a horizontal connector between them.

Three-Dimensional Trusses

The basic system of triangular supports can also be applied to a three-dimensional space. Space frames are a framework of tetrahedrons, which are like hollow pyramids composed of six rods connected at the nodes. When they are arrayed in large numbers, Space frame trusses are able to create strong, flat surfaces.