MSD prevention in plastering and insulation: measuring on-site constraints with Wereystenger

How do you prioritize prevention measures when physical exertion is part of the job? Committed to the TMS Pros program, the plastering and insulation company Wereystenger chose to measure the physical strain on its workers at its active job sites. Twelve interviews, nine workers equipped with sensors, and 31 hours of measurements helped identify five key areas for improvement and a plan featuring twenty solutions, prioritized in collaboration with the teams.

Sector: Construction – Plastering, insulation, fibrous plaster‍

Service: Ergonomic assessment, interviews, sensor-based measurements, co-construction workshops

Timeline: January to April

The starting point

Bags of plaster, ceiling work, cramped residential job sites: in the plastering and insulation trade, physical exertion is a daily reality. Wereystenger, which operates from three branches in Alsace and the Île-de-France region, is well aware of these challenges.

When the Carsat Alsace-Moselle invited them to join the TMS Pros program, which supports companies whose trades involve high exposure to occupational wear and tear, management wanted to make the most of it: to know exactly which situations to address first, and on what basis.

The stakes go beyond workplace health. Attracting new talent, passing on expertise, and keeping experienced workers employed all depend on sustainable working conditions.

Understanding situations requires understanding personal experience

The first phase was based on twelve interviews conducted across seven roles: workers (plasterers, drywallers, fibrous plasterers, team leaders), site managers, the design office, human resources, branch management, general management, and occupational health services. In total, 266 mentions of MSD risk factors were identified.

• ‍The weight of materials is cited by everyone. "Standard drywall is fine, but when you're lugging around the heavy-duty stuff, it's a different story."
• Physical exertion is seen as a given in the trade, rather than a risk. "For ceilings, you've got to have your arms up; there's no real choice."
• Site access dictates the constraints. "When there's plenty of room, you can use a drywall lift and it's fine. When it's tight and cramped, it's much more complicated."
• Demands are increasing: deadlines, working alongside other trades, and a wider variety of products. "We used to have 4 types to deal with, now we have 25."
• Age shapes the teams, between "the young ones" and "the veterans", which raises the question of knowledge transfer.

These accounts provided an initial map of the constraints. The next step was to determine which ones actually weigh the most, and where.

Our method: measuring the work as it's actually done

Six contrasting situations

Interviews were used to select situations representative of the diversity of construction sites: heavy materials, confined spaces, overhead work, and multi-trade coordination. MOTEN ergonomists monitored workers across six of these:

1. Partition installation
2. Renovation of a plaster arch
3. Plastering (second coat)
4. Acoustic ceiling installation
5. Installation of lighting supports
6. Fibrous plaster workshop work

Sensors worn by workers

Nine volunteer workers each wore six MOTEN sensors, placed on both sides of the body on the shoulders (deltoids), arms (biceps), and back (longissimus muscles). Measurements were taken in real-world conditions, both on-site and in the workshop, and supplemented by video observations. In total: 31 hours of recording and nearly one million data points.

Two indicators

• Muscular effort positions a muscle's activity relative to its maximum, from 0 to 100%.
• Postural risk measures the proportion of time spent in strenuous postures, based on REBA method thresholds.

What the measurements showed

Moderate averages, frequent peaks

Across all activities, average efforts remain moderate, with 5 to 6 points higher on the dominant arm side. However, the average masks the most important finding: 15% of the measurement time is spent in high-intensity effort, exceeding 60% of maximum capacity, totaling nearly 5 cumulative hours. This peak-load profile is characteristic of construction trades.

The back, a blind spot in interviews

Postural risk is quite high and primarily affects the back. This point rarely emerged during interviews, which focused on the weight of materials and overhead work.

Arms raised, a highly repetitive gesture

Approximately 7,000 arm elevations above 60° were measured, averaging 4 per minute, with two-thirds occurring on the right side.

Three categories of critical tasks

1. Core trade tasks, those that provide added value, such as applying or smoothing plaster.
2. Handling and moving heavy loads, particularly boards and bags.
3. Managing access equipment for working at heights: climbing onto or moving this equipment requires significant physical effort.

Some of these constraints depend directly on organization. For partitions, cutting or marking on a workbench rather than on the floor reduces postural risk. On the arch, having a colleague supply materials from the ground to the person working on the scaffolding changes the posture for everyone involved.

What Wereystenger did with the findings

The results were presented and discussed in a steering committee. They highlighted five areas for improvement, common to all situations:

1. Reduce the weight of materials or provide assistance for handling them
2. Reduce the number of times the back must be bent during a single work task
3. Reduce or alleviate the repetitive nature of tasks performed with arms raised
4. Maintain healthy co-activity with other trades
5. Ensure the proper functioning of machinery on site

These areas formed the basis for two workshops. The first, held in person, brought together volunteer team leaders and site managers to discuss the solutions proposed by our ergonomists, without budget or feasibility constraints at this stage. The second, with decision-makers, was used to prioritize these ideas and validate the action plan.

A twenty-solution plan

For each area, we proposed concrete solutions, whether technical, organizational, or human-focused. The action plan includes twenty of them. Each was evaluated based on its ease of implementation, expected impact, and acceptance by the workers.

Lightening the load

The weight of materials, cited by all the workers, is where most solutions are focused. In terms of equipment, the plan provides for a board trolley on every active job site and lifting clamps for gripping the boards.

Regarding materials, Wereystenger will test lighter boards and plaster bags on selected sites. A pilot project will also replace heavy boards with two lighter, easier-to-handle ones.

Less bending, less reaching

To limit back strain, plasterers will be provided with foldable bucket holders that keep materials at hand level. Every site will be equipped with a variable-height pallet truck.

The location of cutting areas will be integrated into the site preparation phase. The goal is to cut on a workbench rather than on the floor, as measurements on the partitions had indicated.

For ceiling work, the company plans to test an upper-limb exoskeleton for repetitive tasks involving overhead work.

Organizing in advance

Some solutions are implemented even before arriving on site. A six-month planning board is intended to facilitate communication between sales, the design office, site managers, and management.

Projects will also be categorized based on criteria that include working conditions.

Prevention shared by all

Several initiatives are aimed at all employees, both on-site and in the office. A weekly 15-minute safety briefing will be led by site managers. Awareness sessions will focus on MSDs and manual handling.

Working with a physical therapist, the company is also considering a muscle-strengthening program and warm-ups tailored to the plastering trade.

At the time the plan was approved, five actions were already underway, including the board trolley, the variable-height pallet truck, and the exoskeleton test.

"The workers know their trade better than anyone. Measurement doesn't replace their input: it helps prioritize what they describe, and sometimes highlights things they no longer mention, like back pain." - Marie-Anne Grangeret, Partner & COO, MOTEN

Key takeaways

• Measurement complements perception. Workers primarily cited weight and overhead work; sensors also highlighted back strain and peak exertion levels.
• Averages are not enough. On-site, the risk lies in peak loads and repetitive movements.
• Organization is a key lever in its own right. Workstation layout, supply chain, co-activity, and equipment condition: many constraints can be addressed without changing the core trade tasks.
• Involving teams makes taking action easier. Sharing results in committee meetings, followed by workshops with those actually doing the work, leads to an action plan that everyone understands.

Are you involved in a TMS Pros program, or are you looking to objectively assess your teams' constraints before choosing solutions? Let's discuss your situation.