

Solution: Two-Mason Lift Technique

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	Description:	12” concrete block (CMU) can weigh from 45 to 65 pounds. At most worksites, 12” CMU is handled by one mason, which could increase the risk of low back injuries. As an alternative, a two-mason lift team can be used which helps to distribute the load between two masons. Two-mason lift teams consist of a “lead” mason and an “assistant” mason. To use a two-mason lift team, both masons lay the bed of mortar. While the lead mason completes this task, the assistant mason “butters” the next block to be laid, while keeping the block resting on the supply stack. When the block is ready to be positioned, each mason holds on to one end of the block and lays the block together. While the lead mason is scraping off excess mortar, the assistant mason prepares the next block. More Detail
	Risks Addressed:	Manual material handling (heavy lifting) and static postures while placing block
	How Risks are Reduced:	The use of two-mason lift teams reduces the strain of repetitive heavy lifting and twisting that leads to many musculoskeletal disorders reported by masonry workers.
	Quality of Evidence (Risk Reduction):	Independent published studies have found a risk reduction. Manufacturers, vendors, or worksites have reported a risk reduction. Safety and health experts believe there is a risk reduction.
	Quality of Evidence Explanation (Risk Reduction):	Researchers at Eastern Washington University and the University of Oregon had masons build six course walls individually and with the use of a two-mason lift team, while body posture and muscle activity was measured. Less trunk bending and low back muscle activity was needed when using the two-mason lift technique, compared to handling 12” block alone. However, at the higher courses, greater shoulder elevation was necessary when using a two-mason lift team. These findings suggest that the two-mason lift technique is safer than building a wall individually, except above shoulder height. It is recommended that scaffolding be adjusted to keep lifting between the knees and shoulder height.
	Effects on Productivity:	There is concern that the use of lift teams is less productive. However, studies have shown that using a two-mason lift team may improve productivity.
	Quality of Evidence (Effects on Productivity):	Independent published studies have found an increase in productivity. Safety and health experts believe there is an increase in productivity.
	Quality of Evidence Explanation (Effects on Productivity):	Researchers at Eastern Washington University and the University of Oregon had masons build walls six courses high individually and with the use of a two-mason lift team. The 36 block wall took masons working alone about 27 minutes to complete, which means that two masons working individually could build the wall in about 13 minutes. In contrast, the two person teams averaged approximately 16 minutes to build the same wall, which suggests that two-mason lift teams may be less productive than masons working alone. However, it is likely that the two person method substantially reduces fatigue over the course of the work day or work week compared to a mason working alone. Since this study was only 15 to 30 minutes long, it could not measure the effect of fatigue over a work day. Studies over an entire working day would be necessary to accurately compare the productivity of the two methods.
	Return on Investment:	To calculate the return on investment (ROI) for your specific application, please visit our Return on Investment Calculator. While a specific ROI example has not been developed for this particular solution, the ROI Calculator provides a useful tool and guidance on how to generate your own on investment analysis.
	Availability:	Lift teams are used infrequently by masons. However, union contracts often require the use of two-mason lift teams for 12" CMU.
	Additional Considerations:	Although two-mason lift teams may be safe to use when laying block between knee and shoulder height, lift teams are not recommended for laying courses above shoulder height. In fact, it is not recommended that an individual mason handle block above shoulder height. Instead, scaffold height should frequently be adjusted to maintain lifting between knee and shoulder height.
	Contributors:	Dan Anton, PT, PhD, ATC – Eastern Washington University, and Alysha Meyers, PhD – University of Iowa
	Hazards Addressed:	Masonry, Tile, Cement & Plaster Cut bricks, blocks, stone, concrete, tile or terrazzo Lifting and Carrying (Manual Materials Handling) Lay or set brick, block, stone, tile, or marble Lifting and Carrying (Manual Materials Handling) Overhead work Rig and transport bricks, blocks, stone, tile, terrazzo or marble Lifting and Carrying (Manual Materials Handling)