The winter months in Alberta can be a beautiful time; the purple-blue shades of the snow-topped Rockies; endless glittering fields stretching across the prairies, and bright sunlight sparkling in icicles hanging from the rooftops.
But wait! Those dramatic icicles can actually be a sign of a significant hazard to your home.
Large groups or rows of icicles are often a sign of an ice dam, a buildup along the lower edge of your roofline that can block your eavestroughs and cause significant damage to your shingles, siding, attic and more.
And the result of all that damage is decidedly not very pretty.
What is an ice dam?
In practical terms, ice dams are easy to understand. First, it’s important to note that ice dams usually only occur if the air temperature underneath your roof (in the attic) is warmer than 0 degrees. Since temperatures in Alberta can fluctuate wildly in the winter – especially where chinooks are common – your roof can heat quickly in the sunshine.
The warm sun heats up the shingles, and combined with the warmer air under the roof, begins to melt any accumulated snow. When snow on the higher part of your roof melts, it trickles downwards to your eaves, which have a generally cooler surface temperature. That trickle of water can re-freeze instead of draining away through your downspouts, and as this process continues, ice can gradually build up, becoming a large, natural dam.
This mass of ice can block additional snowmelt from flowing off your roof, which can actually begin to create pools of water on your shingles, away from the drainage of your eavestroughs. Water can eventually leak through the roof sheathing and enter your attic, where it can soak your insulation, degrade its performance, and eventually make its way into your ceiling and drywall.
To top it all off, an ice dam can become fairly heavy, stressing your eavestroughs and if it breaks free, possibly even injuring someone walking underneath it. Needless to say, an ice dam is not an attractive feature on roof.
Short term fixes
So, what can you do to prevent these damaging nuisances?
- For starters, keep your eavestroughs and downspouts clear of debris that can obstruct proper water drainage.
- After a heavy snowfall, use a rake to gently clear roughly a metre of snow from around the lower edge of your roof and soffit. Remember, do not go up on your roof to remove snow in the winter!
- Consider applying a little de-icing material commonly used for melting ice on sidewalks to the affected areas to prevent ice buildup. Make sure you’re using a calcium chloride formula, as other types can damage the grass, siding or paint on your home around your downspout when it eventually melts off.
- As stated above, never climb up on your roof during the winter; however, if conditions allow you to safely set up a ladder, you may be able to gently chip the ice away by hand until you can see there’s enough space in the eavestrough for melted water to flow. You’ll have to continually repeat this process however, making it a less than ideal solution.
- Finally, consider hiring a professional. Make sure the person you hire has the proper equipment (a steamer, for example) and doesn’t use a power washer, which could damage your roof.
Long term fixes
For lasting results, there are more involved ways to improve your home and attic.
To begin with, a well-ventilated attic can prevent ice dams by keeping cooler air circulating around the rafters, just under your roof deck. Your roof surface remains cold enough that snow won’t melt; and while it may seem counter-intuitive, a cooler attic is better for preventing ice dams.
One sure way to improve your attic’s ventilation is by installing channels or ‘baffles’ that run vertically from the soffits up to the roof peak, just under the roof surface. Cold air from outside travels up these insulated channels, creating a ‘cold barrier’ that prevents warmer air in your attic from affecting the roof.
You can also lower temperatures next to your roof by insulating the ceiling of your living space underneath the attic or insulating the inside surface of your roof. This will prevent heat from rising from your living spaces up to the roof deck, heating it to the point it can melt snow.
Heat can enter your attic from unexpected sources; for instance, older, less energy-efficient recessed light fixtures set into your ceiling below the attic can radiate unwanted heat into the attic space. Bathroom exhaust fans, heat vents and other ductwork can also contribute to rising temperatures in your attic. Remember to check pipes and chimneys that travel up into the attic as well, and ensure you wrap them with appropriate insulation to resist heat loss.
If you’re proactive about keeping ice dams from building up on your home, you can relax and chill out inside all winter long, without any worries.