Ice dams and icicles are a fact of life in snowy areas of the province, but they can be reduced and even eliminated with proper insulation and venting.
Ice dams form because the edges of a home’s roof are colder than the upper regions (where more insulation is below), causing ice to form around the eaves. Other times, this scenario occurs because of a warm attic, where warm air escapes into the attic and warms the wood and shingles directly above it. Snow melts above, and the melted snow backs up behind a “dam” of ice.
### An ice dam might form when..
– There is snow on the roof
– Average outside temperature is below 32 degrees
– Roof surface temperature is above 32 degrees at its higher end and below 32 degrees at its lower end
### How it forms
1. Indoor heating rises through the ceiling to the attic and warms the roof
2. Snow on the heated part of the roof melts and flows down until it reaches that part of the roof that is below 32 degrees. Water freezes into an ice dam
3. The dam grows as it is fed by melting snow above, but water held by the dam bcks up and stays liquid
4. Eventually the water finds cracks in the roof covering and flows into the attic, from where it could seep through the ceiling and interior walls.
If you have ever experienced an ice dam on your roofline, you know what kind of a nightmare it can be. For more tips on how to prevent an ice dam, click [HERE](http://www.familyhandyman.com/roof/prevent-ice-dams/view-all).
