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Icicles may be a common sight during Ontario winters, but excessive icicle formation and ice damming can cause serious problems for your home or building. An ice dam is a ridge of ice that forms along the edge of a sloped roof, typically at the eaves. As the ice builds up, it can block normal roof drainage and prevent melting snow from flowing away from the building.

When water becomes trapped behind an ice dam, it can seep beneath roofing materials and leak into the building. This can result in water damage to insulation, drywall, ceilings and interior finishes. Repeated ice damming can also damage roofing materials, eavestroughs and other components of your roof system.

What Causes Ice Damming?

Ice dams are often caused by heat loss from the living space into the attic. Warm air escaping into the attic can heat the underside of the roof, causing snow on the roof to melt. The melted snow then flows toward the colder roof edges, where it refreezes and creates an ice dam.

While there are several temporary ways to manage ice dams, the most effective approach is to address the underlying cause.

How to Prevent Ice Dams

There are several methods used to manage ice damming, including:

• Ice and water shield: Provides an additional layer of protection against water that gets underneath roofing materials.
• Heat trace cables: Help prevent ice from accumulating along roof edges by providing heat during cold weather. However, they require electricity and treat the symptoms rather than the underlying cause.
• Attic air sealing: Helps prevent warm, conditioned air from escaping into the attic and heating the roof.
• Attic insulation: Proper insulation reduces heat transfer between the living space and attic.
• Attic ventilation: Proper ventilation helps maintain a colder, more consistent roof temperature and allows moisture and excess heat to escape.

In many cases, the most effective ice dam prevention solution is a combination of air sealing, attic insulation and proper attic ventilation.

Professional Ice Damming Solutions

At Horizon Contracting, we have the experience to identify the underlying causes of ice damming and recommend practical, long-term solutions. Rather than simply treating the ice buildup, we focus on addressing the heat loss and ventilation issues that contribute to ice dams in the first place.

Properly addressing ice damming can help prevent costly interior water damage, protect your roof and eaves, and reduce the hazards posed by large icicles that fall.

As an added benefit, improving your attic insulation and air sealing can reduce unwanted heat loss in winter and heat gain in summer, potentially lowering your heating and cooling costs.

If your home or building is experiencing ice damming, icicle buildup or attic heat loss, Horizon Contracting can help identify the problem and develop a long-term solution.

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References:

Ice damming: What it is and tips to avoid it – Wawanesa Canada

How to Permanently Fix Ice Damming – Inspection Works