Dangers Associated With Heavy Snow Loads on Roofs

by Placerville Newswire / Jan 23, 2017 / comments

The City of South Lake Tahoe's Building Division is providing the following information to assist homeowners and commercial property owners in assessing potential hazardous conditions due to the snow load on their properties.

The substantial amount of snow and rain that has fallen in the month of January can create unusually heavy loads on roofs. The snow can act as a sponge absorbing rain, becoming increasingly heavy and posing unexpected stresses to roof structures. In some instances, the risk posed by accumulated snow may be mitigated by safely removing snow from roofs of both commercial buildings and homes. Flat and low pitched roofs, most often found on industrial buildings, are at greatest risk of buckling under heavy snow and ice accumulations. Lower roofs, where snow accumulates from higher roof areas are also vulnerable to damage and collapse. Also, some commercial properties have sections dedicated to the storage and display of seasonal merchandise protected only by light-weight, corrugated metal roofs that are likely not able to sustain excess snow loads. Finally, air-inflated structures that protect athletic fields or similar facilities may be susceptible to increased roof loads imposed by accumulated snow. The following information is provided to help recognize potentially hazardous situations and provide guidance on removing snow from rooftops to minimize the risk to roofs and structures due to accumulated or drifting snow.  

  Tips for removing snow and ice from roofs and other areas 

DO’s

  • Use a snow rake for pitched roofs (available at most hardware stores) to remove snow from your roof.
  • Start from the edge and work your way into the roof.
  • Try to shave the snow down to a 2 or 3 inches on the roof instead of scraping the roof clean, which will risk damage to your shingles or other roof covering.
  • Keep in mind that any metal tool could conduct electricity if it touches a power line.
  • Also, metal tools will do more damage to your roof.
  • Shovel snow from flat roofs throwing the snow over the side away from the building.
  • Most plastic shovels are better, except for the ones with curved blades—those too will do some damage toy our roof.
  • Remove large icicles carefully if they're hanging over doorways and walkways. Consider knocking down icicles through windows using a broom stick.
  • Wear protective headgear and goggles when performing any of these tasks.
  • Consider hiring professionals to do the job. The combination of heights plus ice makes this one of the more dangerous house chores.
  • If you don't hire professionals, at least have someone outside with you in case anything does go wrong
  • Keep gutters and drains clean, free of ice and snow and keep downspouts clean at ground level.
  • Tips for removing snow and ice from roofs and other areas 

DON’T’s

  • Unless approved by a registered professional engineer, don’t add your weight or the weight of equipment to the roof.
  • Don’t use electric heating devices like hair dryers or heat guns to remove snow and ice.
  • Don’t use open-flame devices to remove snow and ice. 
  • Don’t use a ladder until after it is inspected to clear any ice that tends to build up on ladder rungs is wiped clean; and check boots and shoes for ice buildup before climbing the ladder. 

How to Recognize Potentially Hazardous Snow Load on Roofs

  • Sagging roofs
  • Severe roof leaks
  • Cracked or split wood members
  • Bends or ripples in supports
  • Cracks in walls or masonry
  • Sheared off screws from steel frames
  • Sprinkler heads that have dropped down below ceiling tiles
  • Doors that pop open
  • Doors or windows that are difficult to open
  • Bowed utility pipes or conduit attached at ceiling
  • Creaking, cracking or popping sounds

Other Safety Tips for Property Owners

Make sure smoke alarms and carbon monoxide detectors are working.

Check outside fuel and dryer exhaust vents, making sure that they are not obstructed by snow or ice. Never use cooking equipment intended for outside use indoors as a heat source or cooking device. Never use your oven for heat.

Clear snow away from furnace and dryer exhaust vents to prevent carbon monoxide poisoning.

Ice dams can cause major damage to a home or building. Ice dams occur after a heavy snowfall, followed by several days or even weeks of very cold weather. An ice dam is a wall of ice that forms at the edge of the roof, usually at the gutters or soffit. When it forms, the water backs up behind the ice dams and creates a pool. This pool of water can leak into your home and cause damage to your walls, ceilings, insulation and other areas.

Space heaters need space, so use them in a 3-foot circle of safety; free of anything that may catch fire. Space heaters are not designed to replace your central heating system; they are only designed to provide a little extra heat on a temporary basis. So be sure to turn them off when you leave room or go to bed at night.

Clear snow away from downspouts so water has a place to go.

Do not be tempted to use a heat gun or open flame torch to melt the ice; the risk of starting a fire is huge.

Also, please remember to shovel-out fire hydrants in\around your area in case of emergency. 

According to meteorologists, a foot of snow can weigh between 12 to 18 pounds