While all roofs need to be cleared of snow throughout the winter, shallow-pitch and flat roofs are particularly susceptible to accumulations and drifting. If you have one of these roof designs, it’s a good idea to remove snow a little more often than “steeper” sloped roofs.
The weight of snow is a factor of both the depth of snow and its water content. Six inches of “wet” snow can weigh as much as 40 inches of “dry” snow. Most roofs can withstand 20 pounds per square foot of snow. Remember that old snow and new snow can combine to greatly exceed snow load capacity. Don’t forget to consider ice – an inch of ice is equal to a foot of fresh snow.
Whether you’ve just experienced a winter storm that dumped a massive amount of snow or endured a few days of steady snowfall, it’s a wise move to check the amount of snow on your roof. As a rule of thumb, you should clear your roof after 6 inches of snowfall.
Trust your home; it will start sending out “calls for help,” such as cracking, creaking, popping or other unusual noises. This is a sure-fire sign that the snow on your roof is too heavy.
Do you see water spots or warps on your ceiling? Have you noticed cracks in your drywall? Do your doors rub against their frames or is there a gap when closing them? If so, you may not be adequately handling snow buildup on your roof. Act fast to get the snow off your roof.
Once you have determined that you need to clear snow from your roof, call a professional. Doing it yourself is dangerous. You can easily slip, fall and seriously injure yourself.
Ice dams are formed when snow and ice melt and then refreeze around the edge of your roof. These icy blockages can even back up into your shingles and cause water leakage into your ceiling, walls, and insulation. In worst-case scenarios, ice dams can also trigger a roof collapse.
Repairs from ice dams will be expensive. Even at this point, it's important to get the snow off your roof and attack the dam to prevent further damage inside of the house.