Icicles on Gutters: What It Could Mean and How to Address It

February 6, 2023 kellymacdonald

icicles on gutters


Now that we have approached the midpoint of winter, you may be noticing one of the season’s trademark characteristics materializing on roofs and buildings all around you. While picturesque icicle lined rooftops may look lovely on an annual holiday greeting card, in real life their presence can present a host of problems.


Broken GutterWhat’s the Harm in Icicles on Gutters?


An issue that is likely top of mind when icicles appear on gutters, or the edge of a roof surface is the threat of those icicles falling. And with good reason. Their impact can be damaging at best and deadly at worst. Having the icicles carefully and safely removed by a professional is advised, however, their presence can cause harm to the roof system and be a sign of underlying issues within a home.

To prevent the icicles from continuing to form during the winter months, completing an investigation to determine the root cause of the issue is strongly advised.


What Causes Ice DammingWhat Causes the Formation of Icicles on Gutters?


Icicles that form along the lowest point of the roof, often at the gutters, are commonly known as ice damming. This phenomenon occurs regularly throughout Ontario winters due to the climate we experience. For ice damming to occur, three factors are required. First, snow accumulates on roof surfaces. Following the snow accumulation, snow melts and travels down the sloped roof to the lowest point where sub-zero temperatures following the snow melt causes the icicles to form along the edge of the roof.


What Lies Beneath the roofIcicles on Gutters: What Lies Beneath

The second requirement in the equation for ice damming is often the most important when determining what the root issue is that is leading to the formation of icicles. Deficiencies in the attic can disrupt the adequate airflow within the space, making the attic too hot and causing accumulated snow on the roof to melt.


In the days following snow accumulation, it can be helpful to observe the overall snow coverage on roof surfaces. If many roofs are completely snow covered but one is only partially covered, with shingles visible on the top half and snow coverage on the bottom, there could be problems in the attic. In these cases, icicles may not form if the days following snowfall are not below freezing, however, the issue should still be investigated as more than just icicle formation can occur.


Investigating the attic not only helps to identify the root cause of the ice damming, but also to determine if interior leaks, condensation, or potential mold growth are present within the space.

Since the attic is rarely accessed by residents of a home, these issues are usually not identified until it becomes a massive disruption, by way of interior damages to the occupied spaces of the home.


Icicle’s Impact on The Roof System

Build up of snow and ice can be damaging to both the gutter system and the roof shingles. In some cases, the weight of the ice and snow can cause the gutters to become loose or detached, requiring repairs to ensure water drains properly from the roof and to prevent leaks from occurring. More often, the damages resulting from ice damming impact the roof shingles or sheathing. Sometimes, water from the build-up backs up beneath the bottom row of shingles. If there is not a waterproofing underlayment present, the water can potentially seep into the sheathing and poses the threat of causing an interior leak into the home.


Investigating the Attic OverviewInvestigating the Attic

Having adequate airflow in the attic is vitally important to prevent ice damming, condensation, and mold growth. The ventilation systems in place must work together to create synergy within the space. This means, having proper air intake vents along the lowest point of the roof surface to allow cool, outside air in to replace hot air in the attic. Outtake vents along the top sections of the roof, not connected to any interior ducting, will allow the air within the attic to exit, creating adequate ventilation and flow.


Interior ducting should be connected to compatible vents on the roof surface, allowing hot air from spaces like the kitchen or bathroom to exhaust outside of the home. If the ducting or vents are not properly connected, that hot air from the interior has potential to exhaust directly into the attic, creating a hot, humid space. The cool air from the intake vents will not be enough the replace the excess heat, potentially leading to moisture and mold growth from condensation.


A vapour barrier and sufficient insulation are also incredibly important components of the attic, to ensure heat from inside the home stays there. Heat always rises, so especially during the colder, winter months when interior temperatures are higher, it is vital for the vapour barrier and insulation to ensure that heat is not penetrating the attic and making the space too hot, in the same way a disconnected exhaust vent might.


What Are the Solutions for Icicles on Gutters?

There is not one, overall solution for deficiencies in the attic that contribute to ice damming since each case will be unique. This is another reason why inspecting the attic is necessary, rather than trying a solution that worked somewhere else. Although the specific corrections will vary, there are some common repair recommendations.


Installing Additional Outtake Vents

A general rule for creating adequate attic airflow, is for every 300 square feet of attic space there must be a minimum of 1 square foot of ventilation. If a space does not follow this rule, or if the existing ventilation is not adequate, additional outtake vents may be recommended to create additional paths for attic air to escape. The cut-out for the new vent should not be obstructed by building joists and should not exceed ½ inch of the size of the vent on the roof.


Remedying Existing Vent Connections

Disconnected ducting, or piping that was never installed to exhaust through the roof vents to begin with, occurs more commonly than one might think. There have also been numerous instances where an opening was made in the sheathing but is not in use, meaning there is a hole with a shingle covering it. These situations can have great impact on the attic ventilation. Depending on the circumstance, solutions can range from simply reconnecting and sealing the ducting to replacing the section of plywood that has been cut.


Insulation and Vapour Barrier

To ensure interior heat stays within the home, affective insulation and a vapour barrier are vital. If a vapour barrier is not present or has become damaged or ripped, installation of a new vapour barrier between the floor and the insulation may be required.


If the insulation has become displaced or damaged due to interior leaks or mold growth, additional insulation may be recommended. If the existing, displaced insulation has not been damaged or saturated, simply redistributing the insulation may be enough to solve the issue.


Changing Style of Vents

Over the years, we have encountered situations where types and styles of vents were chosen for cosmetic purposes, rather than functionality. It is very important that the different components of the attic are working together to promote adequate ventilation. If the existing intake, outtake, and exhaust vents are not all compatible, installing new ones that are may be recommended.


Installing Baffles

Baffles can be made of various materials, most commonly Styrofoam or wood, and can be helpful in ensuring the air intake soffits do not become blocked by insulation or other items in the attic. The baffle also creates a channel for outside air to pass through, helping to ensure cool outside air can displace warm attic air.


Heat Trace CablesInstalling Heat Trace Cables

In our experience, heat trace cables tend to be the one-size fits all solution many people believe will solve their ice damming issues. While they can be a helpful tool, often, they are not going to combat the issue on their own. Also, underlying issues may still be present in the attic that can cause condensation or mold growth.


Sometimes, heat trace cables may be the only viable solution to icicles on gutters, as there may not be a traditional attic space.


If heat trace cables are being utilized, it is recommended that they are monitored and maintained regularly to ensure they are functioning as intended and that any wear-and-tear is addressed as soon as possible.


If you have a known ice damming issue, observe partial coverage following snow accumulation or are just curious about the state of your attic, Detail Roofing is here to help. Contact us about our attic inspection services and get to the bottom of your icicle issues.

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