Can a truss be built with 2X4 lumber or should it be built with 2X6 or larger?

A truss can be built with 2x4 lumber, especially for light-duty applications or smaller spans. However, for larger spans or heavier loads, using 2x6 or larger lumber is advisable to ensure adequate strength and stability. The choice of lumber size ultimately depends on the specific design requirements, load conditions, and local building codes. Always consult a structural engineer or building professional for guidance on truss design.