Maintenance and Repairs

January 22, 2024 Published by Golden Horseshoe Chapter - By Kelly McDonald

Ice Forming Along Your Eaves? Here’s What You Should Know

From the Volume 18, Winter 2024 issue of the CCI GHC Condo News Magazine

Our roofs are subjected to an array of harsh weather all year round, thanks to the four seasons we experience and the volatility that comes along with them. One of the most prevalent roofing issues this time of year, and one that is unique to the winter season, is ice damming.

An ice dam forms along the eaves or lowest point of the roof, trapping water and leading to potential interior leaks. Often, large icicles form along the roof edge, eliciting immediate concerns from homeowners and managers alike. Falling ice, slip hazards from ice melting and refreezing on the ground, and damages to the roof shingles or eavestroughs are some of the most prominent concerns when ice damming occurs. While these concerns are valid, it’s important to be aware of the hidden harms that come with ice damming and how they can impact a home and its inhabitants.

What Causes Ice Damming?

Before diving into how to address ice damming, it’s crucial to understand why it happens in the first place. Simply put, ice damming occurs when snow accumulates, melts, then refreezes. Depending on the type of winter weather we experience year-to-year, sometimes this phenomenon might be prevalent all season and other times not at all. Significant snowfall and freezing temperatures in the days following snowfall are needed for the ice to form. But if the days following snowfall are freezing, how does the snow melt? This can be attributed to interior heat loss, which alters the temperature of the roof’s surfaces turning the snow to water.

Having the built-up ice carefully and safely removed may be top of mind to mitigate potential hazards or liability, however, it’s equally important to discern the cause of the interior heat loss that is contributing to the ice formation. The presence of ice damming can often signal underlying issues within a home, such as mold growth or condensation. Removing icicles will help to prevent immediate hazards but without addressing the root of the issue, the icicles will return over time and interior issues will continue to fester. Often, even if the roof shingles are in good condition and the ice hasn’t penetrated the roof surfaces, we encounter interior leaks from condensation.

Getting to the Bottom of the Problem

To determine the source of heat loss and factors contributing to ice damming, it’s best to start with the attic. In our continental climate, attics serve an important purpose of regulating interior temperatures, venting interior moist air, and maintaining roof temperatures. Systems within the attic work together to promote ample insulation and airflow, and even seemingly small disruptions can make a significant impact on their overall purpose.

Some key elements to a well-functioning attic include:

• Sufficient and evenly distributed insulation to keep heat within the home
• Air intake vents (soffits) to allow cool outside air in
• Air outtake vents to allow warm air to escape
• Connected and sealed exhaust vents to allow moist interior air (from kitchen, bathroom, or dryer fans) to vent outside

With that in mind, here are some common deficiencies that may impact the functionality of the attic and contribute to ice damming.

Insufficient Insulation

There are several types of attic insulation and varying installation methods. Whether your attic features blown-in, batt, or spray foam insulation, you want to ensure it is evenly distributed and sufficient for the space. If insulation is missing or has become displaced in some areas of the attic, interior heat will rise and disrupt the functionality of the attic. On the underside, the insulation should also be accompanied by a vapour barrier to help keep moist interior air out of the attic.

Blocked Intake Vents

For proper attic airflow, outside air needs to be able to move in through the lower intake soffit vents and out through the upper outtake vents. This becomes an issue if the intake vents are blocked or obstructed, limiting, or completely preventing, cool air from entering the attic space. Common issues can include insulation installed too close to the roof edge, covering the soffit vents, or plywood installed over the soffits, blocking air intake.

Inadequate Outtake Ventilation

As a general rule, there should be approximately one square foot of outtake ventilation for every three-hundred square feet of attic space. Cut outs in the roof sheathing should not exceed half an inch of the size of the vent installed on the roof. For adequate airflow, these vents should not be connected to anything and should not be obstructed by building joists or other attic elements. If an attic does not meet these requirements, if the minimum is not sufficient for the space, or if existing cutouts are obstructed, installation of additional outtake vents may be recommended.

Disconnected Exhaust Vents

It is crucial that connections in the attic for interior spaces like kitchens, bathrooms, and laundry rooms are properly connected and sealed so that warm, moist air is not escaping into the attic. During attic inspections, discovering disconnected ducting or ducts that are not connected to the exhaust vent on the roof, are common issues we’ve encountered. Being close to the vent isn’t good enough, as it leaves room for air leakage to occur and can create issues like condensation and mold growth in the attic.

Incompatible Roof Vents

There are a wide variety of roof vents on the market, however, it is important to ensure the types of vents installed are compatible with what is being vented. If, for example, a vent meant for air outtake is used for venting a bathroom fan, the air leakage mentioned above will occur. Air outtake vents, whether a box vent, a ridge vent, or otherwise, are not meant to be connected to anything and therefore do not have the pieces needed to properly connect to interior ducting. Conversely, an exhaust vent does have the proper connections, and therefore wouldn’t be used as an outtake vent, as it would not be adequate for venting the space.

Finding a Solution

With ice damming, there is not a one-size-fits-all solution. What worked to resolve an ice damming occurrence at one unit may not be the solution for another, as the deficiencies causing heat loss may differ. If ice is forming along the roof edge at multiple units within a complex, each unit should be investigated to figure out what issues are present and how best to correct them.

Since ice damming depends on specific temperature requirements to occur, it’s also important to look out for irregularities that can signify attic deficiencies, even if there is no ice present. In the days following major snowfall, keep an out on the overall snow coverage on roof surfaces. If, for example, all but one roof surface is completely snow covered, with the one only partially covered, it could be a sign that something is awry. If one roof surface has snow coverage only along the bottom part of the roof, while the top is melted and the other roof surfaces are completely covered, it’s likely the melt is occurring due to heat loss. If the outside temperature was causing the melt, it would be occurring more uniformly across all roof surfaces.

Ice forming along your eaves can be cause for concern but having a professional promptly address the issue will result in the best course for corrective action and help mitigate future occurrences.

---

Kelly MacDonald has been happily assisting condominium managers and boards with their roofing related needs at Detail Roofing & Sheet Metal since 2017. In her role of Client Engagement & Events, she is dedicated to providing engaging educational content through regular webinars, in-person seminars, and articles, all to help audiences better understand their roof and how to maximize its lifespan. Kelly is a proud member of the Professional & Business Partners Committee.