When erecting a masonry wall, which tool is used as a straightedge to assure the correct alignment of the block?

The masons level is the most suitable tool for ensuring the correct alignment of blocks when erecting a masonry wall. This tool is specifically designed for use in construction and masonry work, featuring a straightedge with one or more vials that indicate level and plumb. By placing the masons level on top of the blocks, a mason can easily check that each block is level horizontally, as well as vertical alignment, which is crucial for both structural integrity and aesthetic appearance.

Being able to correct any misalignment while laying blocks is essential, and the masons level allows for quick adjustments during the construction process. It provides the necessary precision that ensures the masonry wall is built correctly and will stand the test of time, fulfilling both safety and quality standards in construction.

Other tools, while useful, serve different purposes. A level line can help in establishing a guideline for elevation but doesn't directly indicate if the blocks are level at that moment. A plumb bob is excellent for checking the vertical alignment but does not assist with horizontal levels. A square tool is used primarily to check right angles, not for leveling or alignment across the length of the blocks. Thus, the masons level is the ideal choice in this scenario.