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Occupational Health and Safety & Snow-Covered Roofs: What Are the Risks?

Article 06 - COVER - tensio-maintenance-preventive-déneigement-toiture-batiments-sante-securite-travail

Winter is here in Canada. However, behind this beautiful white coat also hide significant occupational health and safety challenges for organizations.

The tasks involved in preventive building maintenance in winter, from monitoring snow loads to clearing snow from roofs, involve a particularly high level of risk. Despite this, it is not uncommon to find that these risks are often underestimated or misjudged within organizations.

Our team has compiled all the information you need to understand the impact of these occupational health and safety risks, as well as the solutions you can consider to ensure the safety of your personnel during the winter

Occupational Health and Safety Risks Associated With Preventive Maintenance of Buildings in Winter

First of All, What Does Winter Building Maintenance Involve?

  1. Snow monitoring:
    This involves climbing onto the building several times a winter to validate the level of snow load on the roof. This may involve visual validation or random weighing of the snow load.

  2. Partial or total snow removal from the roof: 
    Some organizations choose to entrust snow removal from the roofs of their buildings to their own employees during the winter. This means they have to climb onto the roof to push snow off the roof, particularly in critical areas.

    Important: whether your snow removers are your own employees or external subcontractors, you are still responsible for your buildings, and must therefore ensure the safety of all those who will be on your roofs in winter.

Risks Faced by Workers

Unsurprisingly, these tasks entail health and safety risks for workers, who expose themselves to a high risk of workplace injury or, worse still, death.

The following is a description of the risks and their potential causes: 

Risks Potential Causes
Slips and falls
  • Lack of adequate safety equipment (e.g. harness, helmet, etc.)
  • Lack of safety measures on the roof, despite current regulations (e.g.: adding guardrails all around the roof)
  • Workers not sufficiently aware of risks
  • Roof geometry conducive to slipping (e.g. sloping roof vs. flat roof)
  • Icy surface
Building collapse (partial or total)
  • A snow load that is too heavy, causing a collapse due to poorly performed snow clearing (for example, starting snow clearing from a great distance while moving forward and pushing the snow that accumulates as they go, thus causing an extremely heavy load on a single section of the building).
Frostbite and hypothermia
  • Extreme weather conditions in winter in Quebec (cold and wind)
Electric shock
  • Presence of electrical wires on the roof
Heart attacks
  • Due to excessive physical effort (e.g. during snow removal)
Muscular injuries
  • Due to excessive physical effort (e.g. during snow removal)
Being buried under the snow
  • Caused by the sudden detachment and sliding of snow and ice from the roof

Entrusting Roof Snow Removal to Your Employees Is Not Without Risk!

If you have chosen to entrust snow removal from your buildings' roofs to your own employees, you should be aware that they may not have the occupational health and safety knowledge required for working on the roof, compared with qualified external snow removers who are professionally trained to avoid such risks.

In other words, there's nothing wrong with offering this task to your in-house teams. But you need to make them aware of the risks involved, while ensuring their protection at all times.

What Work Methods Are Available to Safely Clear Snow From the Roof?

In this section, we summarized the information on the CNESST (The Commission for Standards, Equity, Health and Safety at Work in Quebec) website concerning the safe removal of snow from different types of roofs.

First of all, the preferred working method depends on the climatic conditions, the quantity of snow and the place of work (location, dimensions, slope, accessibility, solidity and grip). It will also need to be adapted to different types of roofs, particularly old, recently insulated roofs and flat roofs with obstructions.

Minimum Safety Measures for Working in High Areas

Workers must be protected against falls whenever they are exposed to a fall of more than 3 m (118 in).

To work in high areas, it is important to:

  • Use guardrails (or a warning line)
  • Offer personal protective equipment (PPE) to all responders who must go to your roof, such as a safety harness with energy absorber and a fall arrest connection, securely attached to an anchor point of the right strength using a 16 mm nylon rope and a slider
  • Encourage the use of personal lifting devices that allow people to go on the roof more safely, such as a lifting platform, a cherry picker or even a mast articulating boom lift

Snow Removal From a Flat Roof

  • Adequately circumscribe the snow dumping area and prohibit access to it
  • Establish a snow dumping area protected by a guardrail at the edge of the roof
  • Establish a 2 m (6.56 ft.) buffer zone around the roof with a warning line. This zone will not be cleared of snow.
  • Complete the layout with a U-shaped discharge area approximately 2.5 m (8.2 ft.) wide, protected by a guardrail, at the edge of the roof.

Snow Removal on a Sloping Roof

On sloping roofs, we recommend snow removal starting at the top and working towards the bottom of the roof, in addition to providing fall protection.

Starting snow removal from the bottom of the roof can cause large pieces of snow from the top of the roof to detach and slide off, creating the risk of a fall and subsequent burial under the snow. Sudden detachment of large masses of snow can occur when the roof covering is smooth, as in the case of sheet metal, for example.


3 Measures to Maximize Your Employees’ Health and Safety on Rooftops

To maximize the health and safety of your employees, especially those responsible for preventive building maintenance, it's essential to implement rigorous preventive measures. 

1. Implement a Snow Monitoring and Response Plan to Properly Manage Snow on Your Buildings in Winter

A snow monitoring and response plan will enable you to document all the information concerning snow monitoring and management activities in your organization, from the recurring tasks to be carried out to the protocol to be applied in the event of a collapse, including a description of the roles of each stakeholder.

Our team of structural engineers has put together a comprehensive guide to help you design your own snow monitoring and response plan quickly and easily. Download it for free right here:

2. Raise the Awareness Among Your Teams by Provinding All Stakeholders With Relevant Training on Occupational Health and Safety Related to Snow

Awareness-raising and training are two essential elements in the prevention and control of occupational health and safety risks.

Start by clearly defining the training objectives, such as employee safety, prevention of snow-related risks on roofs, and proper use of protective equipment.

Here's an example of appropriate training content

  • Introduction to snow management on building roofs in Canada
  • Risks and dangers associated with snow management on roofs
  • Current legislation, regulations and standards
  • Personal protective equipment (PPE) and necessary equipment
  • Techniques for working at in elevated areas and on snow-covered roofs
  • Safety and emergency protocols
  • Safe use of snow removal tools and equipment
  • Management of emergencies and critical situations
  • Communication and coordination between teams
  • Awareness of weather conditions and health risks
  • Impact on company reputation and customer confidence
  • Practical skills assessment
Also consider providing your staff with qualified trainers, sessions that are both theoretical and practical, using credible case studies and potential scenarios, and training aids that will help them retain what they have learned.

3. Provide Your Employees With All the Equipment They Need to Ensure Their Safety at Work

We recommend that you opt for personal protective equipment (PPE), a set of articles and devices specially designed to protect an individual's health and safety at work.

PPE is used to minimize risks to the health and safety of individuals by providing physical protection against various hazards such as injuries, occupational diseases and accidents.

Types of personal protective equipment (PPE) to use when working on roofs:
  • Fall arrest equipment: ropes, safety harnesses and fall arrest devices used when working on high areas
  • Helmet
  • Safety footwear suitable for icy surfaces and sloping roofs
  • Fall protection equipment: safety nets and devices to prevent objects from falling and injuring workers who may be on the ground at the edge of your building.
  • Warm clothing to avoid the risk of frostbite or hypothermia (let's not forget that Canadian winters are hard ones!).
It's important to follow the proper guidelines for selecting, fitting, maintaining and using PPE to ensure its effectiveness, and therefore the safety of your employees.

Consider Acquiring a Technological Solution to Maximize the Safety of Your Staff in Winter

Technological solutions are available to help organizations reduce the risks associated with managing snow on building roofs. This is particularly the case with the Tensio system.

Tensio completely eliminates the need for interventions in high areas to assess the level of snow load on your building's roof.

The intelligent sensors included in the Tensio system are installed directly in the steel ceiling structure and then calibrated according to the actual capacity of each critical zone of your roof during winter. Engineering calculations are performed by our team of structural engineers.

The sensor data is then cross-referenced with the weather forecast for the next 7 days, providing a rapid - and above all reliable - view of the potential snow overload risks for each zone of your building roofs.

The intelligent sensors therefore provide extremely precise measurements of the condition of your building's roof structure. Which also means that :

  • Your preventive maintenance staff will no longer need to go on the roof to monitor snow, greatly reducing the risk of falls.

"We have considerably reduced the number of interventions on the roof thanks to the Tensio system. We can now monitor the snow load in real time while reducing perilous visits to the roof.

- Francis Rioux, TBuilding Project Manager Shawinigan 


  • By knowing exactly when it's really necessary to carry out a snow removal operation on your roof, you can limit the number of snow removals to the essentials during the winter. Less snow removal, less risk!
  • Your team can rest easy knowing that Tensio will take care of snow monitoring for them, 24/7. This will also enable them to concentrate on tasks that add greater value to your organization, and which will potentially involve a lower level of accident risk.