Understanding and Preventing Ice Dams

Preventing ice dams is achievable. Ice damming occurs in winter when ice forms and builds upon your home’s roof. It blocks melting snow from draining off your roof. When water collects over time, problems could arise if it gets in your home.

If your roof wasn’t correctly installed and/or the attic area was not properly insulated, the backed-up water will enter the house and cause significant damage. If a reputable company has installed your home’s roofing system, you probably don’t need to worry about ice dams. A rubber membrane should’ve been installed beneath your shingles to block ice and snow.

Ice dams are a result of your home’s internal temperature. When hot air seeps through your home’s attic, it warms the exterior of your roof and melts the snow. Depending on the weather, the melted snow could also refreeze to build on the ice dam further.

They can be challenging to spot if there’s been recent snowfall. However, ice dams typically form in roofs’ eaves and valley areas.

We’ve created this blog to teach you the basics of ice dams. They’re very uncommon, but you may encounter one someday. Once you understand them, you can take steps to prevent them. We will also discuss ice dam removal.

Preventing Ice Dams

Consistently regulating the temperature of your roof is the key to preventing ice dams from forming. We will discuss this below, along with other steps you can take to prevent ice dams.

  1. Sealing leaks to prevent warm indoor air from reaching your home’s attic. Locating and sealing these leaks can be tedious. However, it can be beneficial for preventing ice dams. 

We recommend sealing around wire and plumbing sections, attic hatches and light fixtures. If your attic stays cool, snow won’t continuously melt on your roof. As a bonus, humidity is stopped from entering the attic, which prevents mould from forming.

  1. Cleaning eavestroughs before winter to clear any debris that could support an ice dam. Any blockage can reduce your roof’s drainage and form a strong foundation for ice dams to build on.
  1. Ensuring your home’s attic is thoroughly insulated. Insulation plays a vital role in keeping the heat inside your home. A common problem is insulation being uneven.

To cut some costs, some homeowners choose to have less insulation at the eaves of their roof. This can also be a way for roofing companies to save some money. Homeowners can also upgrade insulation to retain more heat.

  1. Install a metal roof. Ice may still form on metal roofs, but water cannot penetrate the surface. Also, snow and ice are more likely to slide off a smooth surface than standard asphalt shingles.

These options will not only help prevent ice dams. Some will also help you save on energy year-round by reducing heat loss in winter and cool air in summer.

During winters with heavy snowfall, ice dams can be unavoidable despite prevention measures.

ice on the roof

Ice Dam Removal

Removing an ice dam can be very dangerous. The safest bet is to have professionals remove snow and ice from your roof surface, overhangs, eaves and eavestroughs.

If you decide against professional help, avoid these common mistakes:

  1. Never try to knock icicles off your house from the ground. It’s dangerous and won’t solve the problem. Icicles are just byproducts of the ice dam, not the cause.
  1. Avoid ice melters like salt, potassium, calcium, sodium or magnesium. These are highly corrosive to shingles, metal eavestroughs, downspouts and flashings.
  1. Avoid walking on a snow-covered roof. Falls from roofs and possible exposure to electrical wires can be fatal.
  1. Another removal method to avoid is electric heat cables. They require a lot of effort to install and can make shingles brittle. They potentially cause more damage to your roof’s shingles.
  1. Manual removal with tools can also cause significant damage to your roof’s shingles. Even with a roof rake, there is potential for damage to shingles. As we mentioned, it’s also dangerous for homeowners to be on their roofs during winter.


It can be tempting to tackle ice dam removal on your own. 

We recommend contacting a professional roofing company for their guidance. You may be better off leaving the ice dam alone than attempting to remove it.

We hope this article has helped teach you about ice dams. Now that you better understand them, you can take steps to prevent them.

For more detailed information on roof ventilation and ice dams, visit the Canadian Roofing Contractors Association website.

We recommend visiting our website’s blog page for more general roofing information.

January 14, 2021

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