Public Safety Advisory: Potential Roof Collapses

Dangers Associated With Heavy Snow Loads on Roofs

Often, there are reports of roof collapses or buildings with potential structural damage from the weight of snow and ice loads on roofs. In many instances, homes and businesses have to be evacuated as a result of collapses or safety concerns resulting from indications of structural weaknesses. In a normal winter season there may be a handful of such events but in a severe winter season, with heavy snowfall, occurrences become dangerous. Severe roof load conditions are the result of prolonged cold weather and repeated snowstorms and no opportunity for the snow to melt off the roofs.

Homeowners, tenants, and businesses need to be aware of the dangers posed by heavy snow loads on roofs and the warning signs of potential structural weaknesses. In some instances, the risks posed by accumulated snow on roofs can be mitigated by safely removing snow from roofs of both commercial buildings and homes. If cold temperatures and additional snow is forecasted, efforts should be made immediately to safely remove snow from roofs.

How to Recognize Problems with 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, become stiff or jammed
• Doors or windows that are difficult to open
• Bowed utility pipes or conduit attached at ceiling
• Creaking, cracking, or popping sounds

 Tips for Homeowners in removing snow and ice from roofs and other areas

 DO’s

• Consider hiring professionals to do the job. The combination of heights plus ice makes this one of the more dangerous household chores.
• If you don’t hire professionals have someone outside with you in case anything does go wrong.
• 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 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 metal tools conduct electricity if it touches a power line, stay well clear.
• Remove large icicles carefully if they’re hanging over doorways and walkways. Consider knocking down icicles through windows using a broom stick.
• Wear protective equipment when performing any of these tasks.
• Keep gutters and drains clean, free of ice and snow and keep downspouts clear at ground level.

 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 a ladder since ice tends to build up on both the rungs of the ladder and the soles of your boots.
• 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.

According to Meteorologist Tony Petrarca, a cubic foot of dry snow weighs about seven pounds, while a cubic foot of wet snow weighs anywhere from 12 to 18 pounds. So, if it’s possible, hire someone to help with all of the snow clearing.

Other Safety Tips for Homeowners

• Make sure smoke and carbon monoxide detectors are working and have fresh batteries.
• Check all outside exhaust vents for boilers, furnaces, dryers (all combustion equipment) making sure they are not obstructed by snow or ice. Blocked vents may cause a failure in the equipment or cause carbon monoxide to build up inside the structure leading to carbon monoxide poisoning.
• Never use cooking equipment intended for outside use indoors as a heat source or cooking device.
• Never use your oven for heat.
• Space heaters require a 3-foot circle of safety free of all items. 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. Be sure to turn them off when you leave room or go to bed at night.
• If you feel you are in imminent danger, get outside and call 9-1-1.

How to Recognize Problems with Roofs in Commercial Buildings

• Many of the same for residential apply to commercial
• Sagging roof steel – visually deformed
• Severe roof leaks
• Cracked or split wood members
• Bends or ripples in metal supports
• Cracks in walls or masonry
• Cracks in welds of steel construction
• Sheared off screws from steel frames
• Sprinkler heads pushed down below ceiling tiles
• Water puddles where it never has puddled before
• Doors that pop open, become stiff or jammed
• Doors or windows that are difficult to open
• Bowed utility pipes or conduit attached at ceiling
• Creaking, cracking or popping sounds

What to do if you have problems

• Consulting with the Building Inspectors Office, (978) 281-9774 or Fire Department (978) 283-2424.
• If there is imminent danger, evacuate the building and call 911.