A light dusting of snow may make your neighbourhood look like a miniature Christmas scene in a snow globe. It’s delightful unless there is a lot of it. Major snowstorms may drop so much snow that you question the stability of your roof. Should you remove snow from your roof?
Snow removal companies may say yes, snow can weigh more than your roof can hold. However, such a heavy snowfall is rare. You shouldn’t have to remove snow from your roof too frequently. However, occasionally, removing snow from your roof is the prudent thing to do to prevent putting undue stress on the roof truss and risking damage to the rest of your home. So, when you should make the call to a roofer to get the snow removed?
How Much Snow Can My Roof Support?
California building codes require that detached single-family dwellings support 20 pounds per square foot of dead load and an additional 20 pounds per square foot of live load. As it moves and is not part of the roof’s assembly, snow counts as a live load. Therefore, you can anticipate that your roof should hold 20 pounds of snow. In states that receive more snow, such as Alaska, architects may need to design houses to hold over 40 pounds of snow.
Now, you need to know how much snow weighs. Estimating snow weight is a little tricky, as snow weighs more the higher it’s moisture content, and it’s hard to measure that as a homeowner. According to FEMA, the lightest snow may weigh only 3 pounds per square foot, while the heaviest could weigh 21 pounds. Ice is much heavier, at a consistent 57 pounds per square foot.
On average, you can expect your roof to hold four feet of fresh snow, assuming the snow weighs an average of 5 pounds per square foot. This general rule is useful, but it doesn’t always hold true.
You may be able to judge the weight of the latest snowfall by lifting it with your shovel. If it doesn’t compare to your 20-pound weight at the gym, your roof should be fine. Plus, remember that while snow may become “packed” or compressed on your driveway and therefore weighs more, it doesn’t get compressed on your roof.
Still, if you’ve just experienced a major snowfall, local weather authorities and roofers should be able to estimate the weight of the snow and guide you as to whether you need to remove it from your roof.
Should You Remove Snow to Prevent Ice Dams?
Those who are plagued by snow dams (ice build-up on the roof) may blame the snow. As a result, they often pay to get the snow removed from their roof before it can melt. Or, they install a kind of radiant roof heating to melt the snow off.
However, snow is not the root cause of ice dams. Poor ventilation or poor insulation are the two common causes of this issue. Ideally, you would get these issues fixed before winter. If you’ve only now discovered you have ice dam problems, a roofer can do the repairs right away, or melt the ice dam for now and get to the repairs in spring. Leaving an ice dam may cause damage to your shingles.
Hire a Professional for Snow Removal
If you think your roof may be reaching its snow capacity, do not go up there and attempt to remove it yourself. Snowy conditions make it very easy for you to fall from the roof. Further, as you’re not a roofer, you won’t know how to remove snow without damaging the shingles underneath.
Instead, it’s much wiser to call up a professional who is covered by insurance in the case of falls and can remove the snow without damaging your roof.