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Helping prevent snow/ice load roof collapse

Winter storms can bring an array of potential exposures and hazards to property, people and business. Record snowfalls especially present the potential for roof collapse. To help prevent snow/ice-related roof collapse, the following steps should be taken. A structural engineer or qualified professional also should be consulted.

Preparing for the next winter storm [Understanding load capacity]

  • Know how much snow your building can safely handle. Older buildings may be designed to lesser code.
  • Know the load capacity of your roof to prevent compromising its integrity and the potential for roof collapse. 
  • Be aware of the potential impact of drifting snow.
  • Assess the roof and structure inside and out for damage, cracks or corrosion and make repairs.
  • Inspect and clear all roof drains and gutters of debris to avoid ice accumulation, a contributor to roof collapse.
  • Buildings built before 2000 with standing seam metal roofs may have a design weakness. 
  • Buildings with wood bowstring truss roofs are prone to failure due to truss deterioration where it meets the wall.

Develop a plan to safely remove the snow

  • Establish a Snow Removal roof monitoring Plan to know when and how to engage in snow removal before too much snow/ice accumulates. Use of large snow blowers on a heavily, snow-loaded roof may present an excessive load.
  • A Snow Removal Plan should be reviewed by a structural engineer and roofing contractor.
  • Snow removal should be done safely and by trained individuals.
  • If a contractor does the removal, have a signed contract with appropriate language holding you harmless.
  • Ask the contractor to provide proof of adequate insurance coverage. Check with your insurance agent for help.

Develop a contingency plan

  • Develop contingency plans to protect your building, contents, equipment, operations and people.
  • Identify alternate locations or companies to help keep your business operational.
  • Move goods and equipment to alternate locations or cover with tarps to protect them from damage.
  • Identify location of shut-off valves for gas, water and electrical utilities.
  • Be prepared to turn off automatic sprinkler systems.

During the winter storm

  • Monitor amount of snow, ice accumulation and snow drift across the entire roof and along long ridge lines.
  • Implement the Snow Removal Plan and safely monitor snow depth on roofs.
  • When removing snow from roofs, do not block building exits, fire hydrants, or utility valves.
  • Do not place piles where melting snow can cause seepage or flooding inside the building.
  • Know the warning signs of building structure stress and potential for collapse.
  • Contact a structural engineer for immediate inspection if there are signs of structural deflection or damage.
  • Shutdown of gas mains and sprinkler systems may be advisable if collapse is considered likely. Eliminate sources of ignition before turning off sprinkler systems.  Contact the fire department and property insurance company before turning off automatic sprinkler systems.
  • Implement contingency plans if collapse is imminent or has occurred.

After the storm

  • Inspect your property for damage and implement your contingency plan.
  • Prepare for the next storm and make changes to your snow removal and contingency plans as necessary.
  • Report any damage and claims promptly to your insurance agent or broker.

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