Solution Summary: Two-Mason Lift Technique
A two-mason lift technique is a work practice that requires two masons to lay bricks or blocks together; while one is setting, the other is preparing the next unit.
A two-mason lift technique is a work practice that can help reduce heavy lifting and carrying. A two-mason lift team can be used to help to distribute the load between two masons.
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.
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.
Heavy lifting and carrying can cause low back disorders, such as muscle strain or a disc herniation (“slipped disc”), which is bulging of disc material possibly pressing on the spinal cord or nerves that go into the leg. The two-mason lift technique can reduce heavy lifting and carrying by distributing the weight between two workers.
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.
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:
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.
Dan Anton, PT, PhD, ATC – Eastern Washington University, and Alysha Meyers, PhD – University of Iowa
Union contracts often require the use of two-mason lift teams for 12" CMU.