United States
, °F

New York, NY

## My Recent Locations

• ### New York, NY

36° RealFeel® 33°
• ### Miami, FL

70° RealFeel® 76°
• ### Los Angeles, CA

60° RealFeel® 62°

# How to Keep Your Roof from Collapsing

##### March 14, 2013, 7:42:42 AM EDT

Winter nightmares aren't just limited to dangerous roads and extreme cold. With heavy snowfall comes the threat of building damages and collapses.

According to the Massachusetts Emergency Management Agency (MEMA), in the first 48 hours after the Groundhog Day snowstorm, there were more than 80 collapses and buildings with structural weaknesses reported to MEMA.

Snow-related building collapses are usually caused by heavy loads of snow on roofs, so this season has been unique because of the extreme weather. Recent rain and sleet made the situation even worse, since the rain could get soaked up by the snow and add even more weight to roofs.

A cubic foot of dry snow weighs about 6 to 8 pounds, while one cubic foot of packed snow could weigh up to 20 pounds. The same volume of ice can weigh three times this amount.

According to a 2008 report from Structure Magazine, causes of snow-related structural problems normally include roof step snow drift, parapet wall snow drift, gable roof snow drift, open air and freezer (uniform loads across the whole roof), sliding snow and ice dams.

Low-pitched and flat roofs are more vulnerable to snow accumulation; lower roofs are of larger risks as well.

• Consult your local permit issuing authority to find the recorded snow load (the maximum snow expected to fall) in your region.
• Calculate your roof pitch: Divide the "rise" (vertical distance between the peak of the roof and the edge) by the "run" (distance from the peak of your roof to the edge) and convert the fraction to a ratio of 12. (For example, if the rise of your roof is 15 feet, the run is 36 feet, then the pitch = 15 feet / 36 feet = 5:12)

How to spot problems with your building

When you see any of the following problems, call your local building or fire official immediately.
• 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

How to remove snow from your roof

• Use a snow rake for pitched roofs.
• Start from the edge to the peak of the roof.
• Shave the snow down to 2-3 inches instead of scraping the roof clean; don't damage the shingles.
• Plastic shovels are better than metal ones (metal tools conduct electricity and damage roofs).
• Remove large icicles carefully.
• Consider hiring a professional.
• Have someone outside to protect you.
• 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 and your shoes.
• Don't use electric heating devices like heat guns to remove snow and ice.
• Don't use open-flame devices to remove snow and ice.

(Reference: Public Safety Advisory On Potential Roof Collapses by Massachusetts Emergency Management Agency)

Report a Typo

### More Weather News

• #### Spotty snow, freezing drizzle may glaze some surfaces in northeastern US Monday

##### Weather News - December 17, 2017, 6:34:26 PM EST

While no major storms are pressing the northeastern United States in the short-term, milder air will trigger spotty, light snow and freezing drizzle to start the week.

• #### Urduja unloads over 1,000 mm of rain on Philippines; Life-threatening flood risk continues into Monday

##### Weather News - December 17, 2017, 11:19:37 AM EST

Urduja, known globally as Kai-tak, will continue to unleash life-threatening flooding rain and mudslides as it slowly crosses the Philippines into Monday.

• #### Christmas holiday travel disruptions may unfold for central, eastern US

##### Weather News - December 17, 2017, 4:05:30 PM EST

As frigid air plunges into and builds over the central United States, a stormy pattern with snow, ice and rain may unfold from Texas to Maine for Christmas holiday travelers.

• #### Rockies, midwestern US to face return of snow late this week

##### Weather News - December 17, 2017, 6:46:12 PM EST

Those getting a head start on holiday travel across the Rockies and Midwest late this week may be faced with disruptive snow along the way.

• #### Milder air to expand across more of midwestern, northeastern US into early week

##### Weather News - December 17, 2017, 1:27:13 AM EST

While waves of arctic air will continue to pour across the Great Lakes and New England this weekend, milder air will surge farther northward early this week.

• #### Waves of cold to invade US in days leading up to Christmas

##### Weather News - December 17, 2017, 1:40:30 PM EST

The cold reprieve unfolding across the United States will not last long with waves of chilly air set to invade many parts of the country in the days leading up to Christmas.

• #### Thomas Fire becomes third largest in California’s history as firefighters face strong winds this weekend

##### Weather News - December 17, 2017, 10:27:41 AM EST

Winds will again kick up and become strong, raising the risk of rapidly spreading wildfires in Southern California through Sunday as firefighters continue to battle the historic Thomas Fire.

• #### Rain, snow to snarl travel in northwestern US this week

##### Weather News - December 17, 2017, 1:15:27 PM EST

After an unseasonably quiet start to December in the northwestern United States, a significant storm will set its sights on the region spanning Tuesday to Wednesday.