Every winter, many roofs collapse due to heavy snow or ice loads. Add rain or heavy, wet snowfalls on top and you’ve got a dangerous combination.
Often roofs collapse suddenly, giving occupants little, if any, warning to evacuate the building.
A roof collapse can happen to new and old buildings alike and cause extensive damage to the building and contents. Low pitched and flat roofs are most susceptible to collapses.
Most roof designs can handle snow loads of 20-40 lbs per square foot. But, as the chart below shows, packed snow with ice can easily overload a roof.
SNOW TYPE APPROXIMATE DENSITY*
Light and Fluffy 5-20
Packed with Ice 40-58
*lbs per square foot for every 12″ of depth
Watch for ice build up on the edge and valleys of your roof. When heat escapes through your attic, it melts the snow. When this water freezes at the edge of your roof, it forms an ice dam and allows water to back up and enter the building under the shingles and wood decking. Besides adding extra weight to your roof, ice dams can cause extensive water damage inside.
Excessive accumulations of snow and ice will require removal.
**For safe removal that won’t endanger you or damage your roof, consult a roofing contractor. Be certain the contractor is covered by WSIB (Workers Compensation) and provides you with a current liability insurance certificate.
NOT RECOMMENDED, BUT
IF YOU ARE REMOVING THE SNOW ON YOUR OWN, BE VERY CAREFUL AS THE ROOF CAN BE VERY SLIPPERY.
1. Choose a pair of boots with excellent traction.
2. Choose a proper shovel. A plastic bucket (scoop) shovel with a large handle is best so you can scoop and slide the snow off the roof’s edge.
3. Don’t pick or chip at ice near the roof surface or dig deep as you may damage the shingles and shorten the roof’s life expectancy.
4. Do not pile all the snow in one area before removing it. This may overstress that section of the roof causing it to collapse.
5. Be safe, not sorry. Consider your options carefully.