Ice Damming? What, Why and How?

Ice Damming? What, Why and How?

Throughout Canadian winters your roof goes through freeze/thaw cycles. You may notice that large icicles and/or blocks of ice have formed in your eavestroughs or at the edge of your roof. This is called Ice Damming. Unfortunately, in Canada’s harsh winter climate, Ice damming is not entirely avoidable. However, by following the steps listed below, you can greatly reduce the chances of ice damming and leaks into your home.

example of Ice damming
Ice Damming in Ontario

What is an Ice Dam? 

An Ice Dam is a wall of frozen water that forms in your eavestrough and on the edge of your roof. This frozen wall prevents other water and melted snow from properly draining off your roof and away from your home’s foundation. This trapped water is forced back up the roof and under your shingles, leaking into your home. A leaking roof can cause serious water damage to walls, ceilings, insulation and even the foundation of your home. Water leaking in to your home can lead to secondary risks like mold and algae growth, which can cause dangerous respiratory problems in the future.

What causes Ice damming? 

An Ice Dam will begin to form when hot air escaping from your house, meet cold air and cold snow on your roof. The heat exposed snow begins to melt and run down the roof, as the melt water hits the colder, unexposed snow it begins to freeze. This thawing and freezing creates the ice dam. As the ice dam becomes larger, trapped water will begin to back up behind it and leak under shingles or into cracks and openings on the exterior of your roof. Water leaking into your roof can damage or stain walls and ceilings. 

Preventing Ice Damming

Ice dams are never completely avoidable, but please follow the tips below to decrease your chances of them forming in the future. 

  1. Find the areas of your home where hot air is escaping into spaces next to your roof deck, like your attic and exterior walls. Seal all leaks if possible. 
  2. Examine your insulation, an improperly insulated home can lead to ice damming and heat loss, increasing electricity and repair costs. 
  3. Make sure your roof and attic is properly vented. Trapped hot air will cause condensation that can promote mold growth in your attic.
  4. Using calcium chloride ice melter, NOT SALT, will also work to melt ice dams and free trapped water.  
  5. Please hire a professional for any dangerous work. Using a roof rake or shovel to scrape the snow down off of your roof after a snowfall can help in preventing water from becoming trapped on your roof as well. Be sure not to push the snow up your roof as shingles can be damaged.

For more information about preventative maintenance please follow the link below to our Preventive Maintenance page.

If your attic is in need of new insulation we recommend the experts at Great Northern Insulation. Visit them here