Snowstorms and cold weather can pose several risks to employees and the public. Sometimes, large amounts of snow also pose a risk to a business property. This information will help you identify if snow-load damage is a risk to your business and provide tips for planning safe removal.
Do I need to worry about snow load damage?
The danger posed to rooftops depends on the construction type, building age, roof condition, and structural design. These factors should be evaluated by a licensed professional engineer prior to winter. The engineer will determine what the roof can safely accommodate and if any alterations to the structure have made it more susceptible to snow load damage.
As a business owner, having a regular pre-season inspection will help keep the building safe during the winter. These include:
- Making sure gutters and downspouts are in good repair and clear of debris.
- Looking for areas where water accumulates on the roof (dips, near equipment, etc.).
- Identifying and fixing leaks or weak spots in roof.
- Making sure the roof heating system or coils are working properly (if applicable).
How much snow is too much?
Keep in mind that a single large snowstorm does not necessarily pose a risk. The danger can sometimes come from a series of storms in which snow accumulates. The characteristics of snow can vary widely from storm to storm: powdery snow, wet snow, melted snow/ice buildup, etc. The total buildup created by multiple storms is called a “snow event”.
The amount of snow on the ground is not an indicator of how much snow is on the roof. Snow can accumulate faster along parapets, heating/cooling equipment, or edges of the roof. According to the Insurance Institute for Business & Home Safety, a roof is in the “danger zone” when the snow on the roof exceeds:
- 4 feet of fresh snow
- 2 feet of packed/old snow
- 4 inches of ice
If your roof is in this danger zone, you should consider having the snow removed from the roof. Evacuate the building promptly if any of the following occur:
- Sagging ceiling tiles, boards, or sprinklers
- Popping, creaking, or cracking noises
- Sagging or bowing roof members
- Doors and windows that can no longer be opened or closed
- Cracks in walls/masonry
- Severe roof leaks
How do I remove snow safely from these areas?
It is important to plan for snow events before they happen. This may include assigning tasks, responsibility, deciding at what point snow should be removed, and/or selecting a snow removal contractor. There are significant risks associated with removing snow from a roof. If you cannot do the job safely, it is best to hire a professional contractor who specializes in rooftop snow removal.
When removing snow from a rooftop, keep the following safety tips in mind:
- Use the appropriate fall protection where applicable.
- Mark the location of skylights, equipment, vents, etc. with flags or something similar. Snowfall can sometimes cover these hazards and cause injury to a worker.
- Locate and designate areas for the removed snow away from entrances, exits, canopies, and building equipment.
- Have someone below the roof to keep traffic away from locations of falling snow or ice.
- Do not use shovels or snow blowers. Use a push broom or roof rake. Do not pull the snow back against the slope of the roof as this may result in shingle damage.
- If using a roof rake from the ground, maintain a good distance away from the eave. The snow can slide at any time, causing an injury if you are too close.
- Remove drifted snow at roof elevation changes (parapets, around equipment, etc.) first, then remove the remaining snow.
Federal Emergency Management Agency (FEMA). (2013, January). Snow Load Safety Guide. Risk Management Series, FEMA P-957.
Insurance Institute for Business and Home Safety. (2019, January). Commercial Roof Snow Load Risks. Retrieved from Organization Website: https://disastersafety.org/ibhs/snow-load-risks-commercial/