What are boards called that are joined side-by-side to line an excavation?

The term for boards that are joined side-by-side to line an excavation is lagging. Lagging is typically used in trenching operations to provide support for the soil and prevent it from collapsing while work is being conducted in the excavation. It serves as a barrier that retains the earth around the excavation site, allowing workers to access the area safely.

Lagging is usually made from timber or other materials and is placed horizontally between vertical supports like sheeting or soldier piles. This method is crucial in ensuring the safety and stability of excavations, especially in environments where soil conditions may be unstable or prone to shifting.

In contrast, bracing refers to the use of diagonal supports to prevent lateral movement during an excavation. Shoring generally describes the overall process of temporarily supporting a structure or excavation to prevent collapse. Formwork is a construction term associated with molds that hold concrete in place until it hardens. Each of these terms references different components or methods of excavation support, but lagging specifically addresses the boards that are aligned in this manner for lining an excavation.