What is a beam that spans an opening in a masonry wall called?

A beam that spans an opening in a masonry wall is known as a lintel. Lintels are horizontal beams that provide support above openings such as doors and windows, allowing the weight of the structure above to be safely transferred around the opening to the masonry wall on either side. This is critical to maintaining the integrity of the wall and preventing structural failure.

In contrast, girders typically refer to larger support beams that may not necessarily span openings but rather provide horizontal support throughout a structure. A grillage is a type of foundation support system that is used for heavy loads and is made up of a series of beams or timbers, while trusses are engineered frameworks that support roofs or other loads over a distance and are not specifically designed for spanning openings in walls. Each of these terms relates to different structural functions, making it essential to distinguish between them in building construction contexts.