How to prevent ice dams from forming on a roof with foam insulation

Due to cold winters and regular snowfalls, residents of Quebec and Canada are no strangers to ice dams and icicles forming on rooftops.

If you are familiar with these ice dams, you may have heard that their weight can compromise the roof structure and cause serious damage to your eavestroughs, insulation and drywall.

In this article, find out how ice dams and icicles form and how applying foam insulation in certain areas may prevent them from forming.

What is an ice dam?

An ice dam consists of melt water that solidifies on the edge of a home’s roof, usually under a layer of snow. The formation of ice stalactites often indicates that an ice dam has also formed on a roof.

They are called dams because they prevent water from melting snow from properly draining off the roof. Instead, the dam causes the trapped water to rise under the shingles or tiles and then seep into the attic or exterior walls. Once the water passes through the building envelope, it deteriorates insulation and construction materials.

How do ice dams form?

Ice dams form when warm air seeps into the attic and heats the roof. Snow and ice on the roof melt and run off under the remaining snow. Once it reaches the area above the soffit, which is usually colder because it protrudes from the building, the water freezes and forms the ice dam. The melt water will either become trapped under the dam and cause water infiltration, or it will flow over the dam and form icicles.

How can foam insulation prevent ice dams from forming?

Since heat transfer through the roof is the main cause of ice dams, insulating the attic with foam insulation can help prevent ice dams by reducing the amount of heat transferred through the roof.

In fact, while it is normal for warmer air to circulate in the attic, it should be exhausted through vents located near the ridge. As a result, you should apply foam insulation to seal all areas where warm air could escape to ensure a watertight roof.  This will help ensure air exchange through the soffits and roof vents. Foam insulation is particularly ideal for this application, since it will expand and seal all openings.

Adfast insulating foams can help you prevent ice dams from forming

In short, applying foam insulation at strategic points in the attic creates a roof that is well sealed against air exchange and prevents heat transfer through the roof. This considerably reduces the chances of an ice dam forming.

If you want to guarantee that the insulating foam you choose to insulate your attic is high-performance and easy to apply, you can always rely on Adfast Adfoam insulating foams and application guns.

For more information on our professional grade products, contact our team!