What are Ice Dams and How to Prevent Them

As if homeowners didn't have enough to worry about during the winter months, ice dams are another cause for concern. And with the frigid temperatures our area has been experiencing lately, one can never be too cautious.

An ice dam is a ridge of ice that forms as the edge of a roof and prevents proper drainage of melting snow and water off that roof. Because that water is trapped behind the ice and cannot drain off, it is possible that it could leak into into your property causing water damage to walls, ceilings and insulation.

Ice dams develop and grow due to differentiating temperatures on your roof. If heat is escaping through your property's roof close to the top, any snow or ice located there will melt and travel downwards, where it may form an ice dam if the roof area nearer the edge is cooler. While it is natural for some heat to escape your home, ice dams could be an indication of serious heat loss or insulation issues.

Take a look at the photos below for an example:

ice dam

ice dam

severe ice dam

severe ice dam

The home on the right clearly shows limited areas of heat loss where there is no snow on the roof. The snow in these small areas has melted and traveled down the roof where it caused the ice dam. A good thing to do for this property would be to check the roof and ceiling area directly underneath this area of missing snow for inadequate insulation, leaks or other issues.

The property on the left illustrates a high level of heat loss from a larger area on the roof. Very little snow is left on the actual roof, having melted and traveled to the edge to create an ice dam.

Preventing Ice Dams

The key to preventing ice dams is simple really -- reduce heat loss from your property via the roof.

  • Ensuring adequate insulation and airtight ceilings will help keep your heat inside your home and not allow it to travel up into your attic.
  • Adding insulation to your roof or attic space can also cut down on heat loss.
  • Removing snow from your roof is another short-term solution. This is risky, however, since roof rakes and snow brushes can damage roofing materials. Not to mention that venturing out onto your roof is highly dangerous and suggested only for professionals.
  • Another temporary solution to an already formed ice dam is to create channels for the melting snow to travel downwards. This can be done by using a hose and spraying warm water onto the ice dam, beginning at the edge and working your way upwards. This will allow drainage, but will only be a temporary fix.

When in doubt, contact your local roofing professional for guidance and preventative measures against ice dams.