What is a Truss?

A wood truss is a pre-fabricated wooden structure that is designed to hold up roofs and ceilings. Trusses are used as an alternative to conventional rafter framing, and are often less expensive. Because trusses are made at an off-the-jobsite facility, they can greatly speed up the framing of a building.

Trusses take advantage of a strong triangular shape to distribute their load evenly. They are held together by metal connection plates at each joint. The metal plate is placed at the desired location and pressed into the wood by a large hydraulic press. The diagram below gives a breakdown of a truss’s components.

Trusses can be made into many shapes, in order to support countless roof designs. The most common roof types are a straight gable roof and a hipped roof. Trusses can be designed with a room built into them; this is referred to as an attic truss. They can also hold other portions of a roof through the use of a girder truss.