Several key differences can help you distinguish girders and beams. Girders tend to be significantly larger than the typical beam, as they are used for the supportive framework. Therefore, large beams are often called girders within construction.
However, there is not a specific cutoff measurement to distinguish girders from beams. To better distinguish between the two, the installation and usage of the object are often examined. Girders and beams are both utilized to resist forces, though they differ in function. Girders are installed perpendicular to structural joists and directly nailed to the framework. They are the main horizontal structural support, serving as the large beam in which the smaller beams are supported. Girders are tasked with carrying a significant amount of support, including dynamic and rolling loads.
On the other hand, beams do not need to give the same degree of support as girders, because they do not support the same amount of structural weight. Beams are more flexible and built and installed to accommodate shear stresses, as opposed to girders which are far stiffer.