Christian Vanasse

By Christian Vanasse

February 28, 2019


8 questions about clearing snow from the roofs of your commercial buildings

Article revised on 13 February 2020

Freezing rain, heavy snowfalls, rise in temperature, strong winds and severe cold. Quebec winters can be unpredictable and can really put your commercial buildings to the test. When significant amounts of snow has accumulated and interspersed with rain, commercial insurance claims involving collapsing roofs or water seepage skyrocket. But how can you protect your commercial buildings from property damage and occupants from the risk of injury that can occur when snow accumulates on the roof? Here’s what you need to know!

1. What are the major risks posed by the accumulation of snow and ice on the roofs of your commercial buildings?

Collapse of your roof

When there’s an abundance of snow or the roof is weighed down by layers of ice caused by rain, the cases of roof collapses increase dramatically. A collapsed roof can have serious consequences:

  • Injury or death caused to people inside the building
  • Damage to the roof and, possibly, to the structure of the building
  • Damage to property and merchandise in the building

Falling snow and ice

When the temperature rises, snow and ice buildup can detach from the roof and, by falling, can cause:

  • Injury or even death to people circulating around the building
  • Blocked emergency exits or other access lanes of the building
  • Property damage, for example to vehicles parked near the building

Water seepage through the roof

This can occur, for example, when a lot of snow melts and the drainage pipes are blocked by ice, causing water to accumulate on the roof. Property damage caused by seepage can be significant.

2. How can you reduce the risk of injury, accidental death and property damage due to snow accumulated on your roof?

As the building owner, you’re liable for the safety of your clients, visitors and tenants. If people are injured because you neglected to maintain the building adequately, not only can you be sued for compensatory damages, but your business is also at risk.

Even though it’s possible for your commercial insurance to help you out in such a situation, you would probably prefer to avoid the negative publicity and countless headaches that can stem from it.

To reduce the risk, make sure that:

  • The building is adequately maintained year-round
  • The roof is regularly cleared of snow during the winter
  • The snow is removed safely
  • The emergency exits are cleared of snow and accessible at all times

3. How much snow accumulation can a roof typically handle?

According to the Association des professionnels de la construction et de l’habitation du Québec (APCHQ), roofs in Quebec are usually designed to withstand approximately 50 lbs of weight per square foot. This weight corresponds to the average precipitation of a standard winter. Since ice is ten times heavier than snow, the type of accumulation is the most important factor to consider when deciding if you should clear your roof of snow.

4. When should the snow be removed?

Since it can be difficult to assess the weight of snow per square foot, experts estimate you should act as soon 30 inches of snow has accumulated. You should, however, keep in mind that this is just an indicator, and you should adapt it to the type of accumulation and the sturdiness of your structure.

5. Is your roof at risk of collapsing?

The Régie du bâtiment du Québec (RBQ) recommends to clear the snow and de-ice the roof of your building immediately if you observe one of the following:

  • Cracks on interior walls
  • Interior doors jamming or rubbing against the frame
  • Conspicuous creaking noises emanating from the building structure
  • Deformation or buckling of a ceiling

If you have any doubts about the sturdiness of your roof or if your building underwent major modifications, the RBQ recommends calling on the services of a structural engineer. This way, you’ll know the condition of the roof structure and how it is impacted by the weight of the snow.

6. Are certain buildings more susceptible to damage caused by the accumulation of snow?

Yes. Commercial or residential buildings with one of the following characteristics require thorough winter maintenance to avoid a roof collapse or water seepage:

  • Flat or low-sloped roofs
  • Roofs with large surface areas
  • Roofs that are more than 20 years old
  • Buildings that are more than 30 years old

7. What are the benefits of signing a snow removal contract for your roof at the start of winter?

By confiding this work to a specialized firm that has all the required insurance coverage, know-how and equipment, you will have peace of mind! There are many benefits:

  • Eliminating a potential major source of stress and concern for the rest of the season
  • Reducing the risk of injury, death and property damage caused to the building’s tenants and visitors
  • Reducing the risk of potential injury to your employees or yourself if you removed the snow yourselves
  • Reducing the risk of damage to your roof surface which can occur if the snow is not removed properly
  • Protecting your investment in your business using sound risk management
  • Saving time and money by avoiding the planning of snow removal and buying the safety material required to protect employees from falls

8. What to do if you decide to remove the snow from your roof yourself.

To avoid injury, follow the recommendations from the Commission des normes, de l’équité, de la santé et de la sécurité du travail (CNESST). In summary:

  • Plan the work properly to ensure everyone’s safety
  • Set up a secured perimeter around the building
  • Ideally, you should start from the ground, using a telescopic shovel designed for clearing snow from roofs
  • If you have to climb up to the roof, purchase adequate safety equipment required to reduce the risk of falls, electrocution, injury and frostbite

Also make sure:

  • To always leave a layer of snow on the roof to protect your waterproof lining
  • That attic plumbing and vents are cleared

 It’s unanimous among specialists: For building owners, there’s no way around the removal of snow from their roofs. It is their responsibility to ensure the safety of people who frequent the building or live within!


Additional resources:

Régie du bâtiment du Québec – Removing snow and de-icing

Infoassurance – Weight of snow

Commission des normes, de l’équité, de la santé et de la sécurité du travail – Déneigement des toits

4 Maintenance Tips for Your Roof

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