The snow and cold are here…and they won’t be leaving us anytime soon!  In this weather, it’s important to keep an eye on your roof. 

Ice dams are a frequent problem in the winter, and they can cause damage not only to the outside of your home, but the inside as well.

What is an ice dam?

In the winter (at least here in New York!), the air in your home is much warmer than the outside air.   When snow falls on your roof, it forms a barrier.  If the warm air from inside your home is able to escape through the roof, it will heat the bottom layer of the snow, which causes it to melt and run down the roof.  When the water reaches the colder edge of the roof, it freezes.  Over time, an ice dam grows.

Can an ice dam cause damage?

Absolutely!  As an ice dam grows, water continues to melt underneath it.  This means that there is pooling water sitting on your shingles.  Believe it or not, shingles are not designed to be water resistant—they are designed to shed water.  When water sits on shingles for extended periods of time, it will result in leaks.  This water will then enter your home, and can cause interior damage to walls, ceilings, insulation, etc. This can happen in even a brand-new roof.

Additionally, ice dams are heavy, and they can result in large icicles hanging from your gutters.  The weight of the dam and the icicles can cause damage to your gutters and overhangs.

What are the main causes of ice dams?

Ice dams are a direct result of warm air escaping your roof.  There are many reasons that this can happen but the main culprits are:

  • Clogged gutters
    • With the early snow this year, many people did not get a chance to clean all of the leaves out of their gutters. These leaves, in turn, block downspouts and fill the gutters, which causes water to be trapped on top instead of flowing through.  This water backs up and then freezes, creating an ice dam.
  • Poor Insulation
    • Not all insulation is created equal. Insulation comes with an “R-value”, which is basically a measure of how well the insulation resists the flow of heat.  In our area, it is recommended that houses have insulation somewhere between R28 and R38. If your insulation has a lower R value, it can allow for too much heat to escape the roof.
    • Additionally, you might not have enough insulation for your home, or your insulation might have begun to degrade.
  • Ventilation
    • Most homes have soffit vents to allow for air intake, and ridge or box vents to allow air to escape. This continuous flow allows for a relatively consistent temperature between the top and underside of the roof.  If you have insufficient ventilation, it will interrupt the air flow, and cause pockets of heat to develop on your roof.
    • Some homes have improperly installed insulation, or even insulation which has settled–which can directly impact your ventilation system. In order for soffit vents to work, there needs to be space between installed insulation and the vent itself.  If insulation is too close to the vent, it can block the air flow.  Baffles are often installed to hold insulation in place and prevent this from happening.

What can be done about ice dams?

  • Short term:
    • Use a snow rake. These typically can be purchased from home improvement stores, and can be used from the ground.  You would remove snow about four feet in from the eaves all around the house.  You would continue to do this throughout the winter.  Clearing the snow gives the water clear channels to drain.
    • Check your gutters—if they are full of leaves, see about removing them.
    • Try calcium chloride tablets to melt some of the ice. Do NOT use salt, as it can damage the shingles.  You do not need to melt the entire dam, just enough to allow for channels for the water to drain.
    • Try heating coils. These will also allow for channels for the water to drain.  Keep an eye on these, however.  If the weather is excessively cold or snowy, they can become less effective. 
    • Do NOT try to chip away at the ice dam using tools or anything sharp. This can cause permanent damage to your roof.
    • Do NOT climb on your roof, or allow anyone without insurance on your roof. A roof can be dangerous even under the best of conditions.  It is not worth risking your life or health.
  • Long term:
    • To prevent ice dams in the long-term, you need to determine their cause. In some cases, it might be an easy fix, like installing baffles or cleaning gutters.  In other cases, it might mean updating your insulation or ventilation system. 


If you are experiencing ice dams, it is important to have a professional evaluate your roof and determine the root cause and best course of action.  Contact us anytime for a free evaluation and educational estimate, 585-400-7663 or