The cost of a roof truss is determined by the design, the lumber used, the size, the roof pitch, and other factors discussed below. It might be difficult to provide a precise cost because so many variables must be considered. The truss alone, without installation or delivery, can be between $35 and $150 per foot,... The first factor that determines the cost of a truss is the type of truss that is needed. There are three types of trusses: open web, closed web, and hybrid. An open-web truss has parallel chords that are spaced evenly apart with no joints in the material. These trusses are easy to build and less expensive than closed-web trusses. They require more material than closed-web trusses but are easier to find in standard sizes. Open-web trusses are most commonly used for frame buildings because they are very strong while using little material. A closed-web truss has perpendicular members at right angles to each other with joints in the material. These trusses are more difficult to build than open-web trusses but they use less material overall. Closed-web trusses are usually specified for larger structures because there's more strength per unit length. They are also useful if you need to keep the weight down such as for a temporary structure.