Tuesday, 20 January 2015

How to Recognize and Prevent Ice Damming

The cold winter season is the time when many homeowners see icicles hanging from their eaves or water coming in the house due to ice damming on the roof. An ice dam is a ridge of ice that forms at the edge of a roof and prevents melting snow/water from draining properly off the roof. The water that then backs up behind the dam can leak into your home and cause damage to walls, ceilings, insulation, and other areas. 

There are three main causes of ice damming:

  • Poor insulation from a house ceiling. An attic with inadequate or deteriorated insulation can cause ice damming.
  • Lack of ventilation. A house with proper ventilation allows the necessary cold air to mix and cool the hot air from the house, which slows the snow melting down.
  • Leaking gaps between the living space and the attic. These spaces allow extra heat to “escape” into the attic, which warms the space and melts even more snow.
Here is what you can do to prevent ice damming:

  • Seal the living space.
  • Install adequate attic insulation.
  • Make sure that the attic is properly ventilated.

Shingle roofs are designed to shed water; they are engineered and installed to reject freestanding water. That is why a good quality leak barrier is needed at the eaves. The most important thing a contractor can do to help homeowners with ice dam problems is to first clean the snow off the roof (following strict safety rules) and then create exits for the trapped water.
Preventing ice dams and icicles may not be possible at all times, but these are measures that can be taken to help stop water from entering the house.


  1. Great article! Mind if I share at http://roofingsalesjob.com?

    1. Hi Denise,

      Absolutely - Share away! Glad you're enjoying the content.