What is the process of leveling a floor or layer of concrete using a straight edge with a back-and-forth motion called?

The process of leveling a floor or a layer of concrete using a straight edge in a back-and-forth motion is referred to as screeding. This technique involves moving a tool, typically a straightedge or screed board, across the surface of the freshly poured concrete to ensure that it is flat and level.

During screeding, excess concrete is removed from the surface, and the layer is brought to the desired grade and uniformity before it sets. This step is crucial because it helps in achieving the required flatness and smoothness, which is essential for the integrity and aesthetics of the final surface.

In this context, troweling pertains to a separate finishing process applied after screeding to further smoothen the surface and can include polishing or texturing. Finishing is a broader term that encompasses all activities to prepare the concrete surface for the final appearance and performance, including troweling and smoothing, but does not specifically refer to the leveling technique itself. Shimming refers to placing thin pieces underneath surfaces to create a level or support which is not applicable in this context of leveling concrete layers.