ice dam diagram

The Problem and Implications of Ice Dams on Roofs

Ice Dams on Roofs: Understanding the Problem and Its Implications

Winter brings with it a unique set of challenges for homeowners, and one of the most frustrating and potentially damaging issues is the formation of ice dams on roofs. Ice dams not only create an unsightly and dangerous situation but can also lead to significant structural and water damage if left unaddressed. In this blog, we will explore what ice dams are, how they form, and why they pose a problem for homeowners.

Understanding Ice Dams on Roofs:

An ice dam is a ridge of ice that forms along the edge of a roof, preventing melting snow from draining off properly. This accumulation of ice occurs when the heat from the interior of a house escapes into the attic or roof space, causing the roof to warm unevenly. As snow accumulates on the roof, the warmer sections cause the snow to melt, and the resulting water flows down the slope of the roof.

The Problematic Formation of ice dams on roofs:

As the melted snow reaches the colder eaves or overhangs of the roof, it refreezes due to the lack of sufficient heat. This process is exacerbated by freezing temperatures, creating a layer of ice along the roof’s edge. Over time, this ice accumulates and forms a dam-like structure that traps subsequent melting snow.

Consequences and Damaging Effects:

  1. Roof Damage: Ice dams can lead to damage to various roofing materials. The weight of the ice itself can put strain on the roof structure, potentially causing sagging or even collapse. Additionally, as the ice melts and refreezes, it can lift shingles, break seals, and compromise the integrity of the roof.
  2. Water Leakage: Perhaps the most immediate concern with ice dams is the potential for water leakage. When the trapped water has nowhere to go, it may seep into the roof, causing leaks and damaging the underlying structure, insulation, ceilings, and walls. This can result in costly repairs and the need for mold remediation.
  3. Gutters and Downspouts: Ice dams can also wreak havoc on gutters and downspouts. The weight and pressure of the ice can cause them to detach or pull away from the roofline, leading to further water drainage issues and potential damage to the exterior of the house.
  4. Siding and Paint Damage: As the water from ice dams flows down the exterior walls, it can seep into the siding or behind the paint, causing discoloration, deterioration, and peeling. This not only compromises the aesthetic appeal of the house but also exposes it to moisture-related problems.

Prevention and Mitigation:

  1. Materials: Using proper materials such as Ice and Water barrier or valley metal greatly reduces your risk for damages caused by ice dams, and is required by current code book adoptions.
  2. Insulation: Proper insulation in the attic is essential to prevent heat from escaping and warming the roof. This helps maintain a consistent temperature across the roof surface and prevents the differential melting and refreezing that leads to ice dam formation.
  3. Ventilation: Adequate ventilation in the attic allows for the removal of warm air and helps keep the roof surface cool. This minimizes the risk of snow melting unevenly and reduces the potential for ice dams.
  4. Roof Raking: Regularly removing snow from the roof using a roof rake can help prevent ice dams from forming. By removing the snow before it has a chance to melt and refreeze, homeowners can mitigate the risk of ice dam formation.
  5. Heat Cables: Installing heat cables along the roof’s edge and in the gutters can provide a source of heat to prevent the formation of ice dams. However, these should be used judiciously and as a temporary solution, as they can be costly to operate and may not address the root cause of the problem.


Ice dams pose a significant problem for homeowners during the winter season. They can result in various forms of damage to the roof, insulation, walls, and overall structure of a house. Understanding the causes and consequences of ice dams is crucial for homeowners to take preventive measures and mitigate the risks. By implementing insulation, ventilation, regular maintenance, and appropriate snow removal practices, homeowners can protect their roofs and ensure a safe and secure living environment during the colder months. Contact us!