Snow Load Exposures on Roof Tops

During the winter months in the Northeast, snow loads on rooftops and decks pose a risk for collapse and severe damage to the building and its integrity. Accumulating snow should be removed from rooftops regularly to prevent costly losses due to collapse. The following measures should be taken to maintain the roof’s integrity.

• Identify high-risk areas around the building where a collapse is likely due to a heavy snow load. These areas may include:
• Large open flat roofs, barrel roofs, roofs with less than 30 degrees of slope, multi level roofs, heavily insulated roofs and pre-engineered roofs on bar joists.
• Roofs with previous structural damage and those that have
  already experienced collapse.
• Areas shaded from direct sunlight that may cause snow to freeze into ice and increase the snow load.
  
• Begin snow removal before it becomes critical.
• Have the roof inspected by a civil engineer to determine the snow load that can be safely handled by the design of the roof. Identify deficiencies and repair.
• Create a roof plot plan to identify skylights, hatches, drains/scuppers, pipes, wiring, load bearing walls, etc…. Include photos with your plot plan. Plot plans should be updated regularly to include any changes made to the rooftops such as added equipment.
• Snow removal should be done by knowledgeable, experienced employees or preferably by outside contractors. Hire only professionals who can provide you with a copy of their insurance certificate. Sign a contract holding you harmless.
• Keep up with preventative maintenance throughout the year to maintain the roof’s integrity.
• Monitor rooftop conditions throughout the winter during a storm to identify ice buildup, snow drifts and blocked drains.
• Special care should be taken when removing snow from rooftops to prevent damage to the roof’s membrane. Follow these guidelines when removing snow:
• Do not remove snow all the way down to the roof covering.
• Use plastic shovels rather than metal.
• Use a plastic tarp to fill with snow and release over the side of the building. Watch areas where snow is landing.
• Adjust snow blowers to prevent rotating components from coming into contact with roof surface.