Maintenance Tip – Preventing Ice Dams

What is an Ice Dam?
Ice dams are formed by continual thawing and refreezing of melting snow. Large masses of ice develop as snow on the upper part of the roof melts. The water runs under the snow and refreezes at the edge of the roof. Additional snow melts and forms pools against the dam gradually causing water to back up the roof often getting under the shingles and eventually leaking into the house.

What causes Ice Dams?

  1. Inadequate attic ventilation
  2. Bright sunshine melting the snow
  3. Poorly placed gutters preventing snow and ice from sliding off the roof
  4. Insufficient attic insulation allowing the heated air of the attic to reach the roof deck and melt the snow

How to prevent Ice Dams?
The goal is to keep the entire roof the same temperature as the eaves. You do that by increasing ventilation, adding insulation, and sealing off every possible air leak that might warm the underside of the roof.

Northern Building Services can help out (just call 905-717-0334).  We can:

  • Install Waterproofing Membrane on eaves and in valleys to prevent water from penetrating the roof
  • Improve attic insulation keeping the attic space cool, to reduce the amount of melting snow
  • Improve attic ventilation to ensure that the attic remains cold
  • Make sure that your gutters or eaves-troughing are lower than the slope of the roof to allow snow and ice to glide off