Free Estimate
Ask about our Financing, 24 months, No Interest!!
Contact Us
Image of icicle on a home and the text: What Causes Ice Dams and How to Prevent Them

What Causes Ice Dams and How to Prevent Them

Ice dams often result in significant structural and financial damage to a home. Knowing what causes ice dams helps homeowners understand what steps they can take to reduce or eliminate them. Some construction contractors theorize that gutters are one potential source of ice damming. But can gutters cause ice dams?

How Ice Dams Form

Ice dams often occur in cold, northern climates with deep snow accumulation. An ice dam is an icy formation (frequently appearing as thick, extended icicles) along the edge of a roof. This impenetrable ridge of ice on the roof’s eave slows or prevents melting snow from draining off the roof – a damming effect results.

Although ice dams most frequently build along the roof’s edge, they also form around skylights, vents, and valleys (any location where two inclined sides of the roof meet). In particular, ice damming is a significant concern for homes with a complex roofing system that includes multiple roof facets (including various ridges).

To better understand how ice dams develop, consider that the melting of snow on a roof arises from three causes. First, the air temperature has to be well below freezing. Second, a thick layer of snow needs to settle on a sloped roof. Third, sufficient building heat must emanate through the roof to force snow to melt.

Icicles forming an ice dam on wood siding home

The Impact Of Ice Dams

Because ice dams prevent melting snow (in the form of water) from draining off the roof, the pooled water seeks an alternative place to drain. In many cases, backed-up water leaks into the home, causing incalculable damage to a home’s ceilings, walls, and insulation. In addition, interior mold and mildew growth often result.

Ice dams also produce exterior damage to a home. The weight of an ice dam weakens structures, including fascia boards, fasteners, gutters, and downspouts. The roof itself also faces challenges. Roof rot can form depending on where the melted snow impedes the roof. Finally, siding problems could develop from excess moisture intrusion.

Many insurance carriers cover the damage caused by ice damming as long as the incident is reported timely. Unfortunately, homeowners may not observe or be aware of the consequences of an ice dam for years. How come? Water damage (including mold and mildew formation) often occurs in hidden areas of homes behind walls and above ceilings.

Snow and ice forming the roof of house

Can Gutters Cause Ice Dams

Bottom line: Gutters do not cause ice dams. As explained previously, ice dams typically occur because melting snow accumulates behind a formation of ice along a roof’s edge. However, because a gutter extends the surface area of the overhang, the existence of a gutter may impact the size and thickness of the ice dam that developed.

Some homeowners remove gutters under the false impression that gutters cause ice dams or significantly worsen the damming effect. In rare instances, a poorly positioned or clogged gutter may contribute in small measure to exacerbate slightly the impact of ice damming. But, most experts agree that gutters do not create ice dams.

Preventing Ice Dams

The most effective way to address ice dams is to take steps to prevent ice damming from occurring. If an ice dam never has a chance to form, the homeowner has peace of mind knowing that no snowfall will cause damage to their home. Many practical and cost-effective measures exist to stop ice dams, including the following solutions:

  • Conduct a home energy audit.

Knowing where heat leaves the home provides a means to block or reroute sources of heat escape away from the roof to channel out through other areas.

  • Ensure sufficient attic insulation.

Ice damming occurs because excess heat escapes the home through the roof, causing snowmelt. Quality attic insulation prevents heat transfer out of the attic.

  • Install a radiant edge system.

This system runs along the roof’s edges to promote the melting of snow, ensuring that water flowing down the roof stays melted while passing through the gutters.

  • Keep gutters clear of debris.

Many times, snowfall will melt upon impact with the roof. Having gutters without debris buildup allows melted snow as water to channel through the gutters safely.

  • Provide adequate attic ventilation.

Reducing heat collection in the attic diminishes the ice-damming effect. Attic and exhaust vents keep air circulating and assist with cooling to offset hot air pooling.

  • Rake snowfall off the roof.

Immediately following a snowfall, proactively (but safely) remove snow from the roof using a snow removal tool like a lightweight roof rake with a long extension.

  • Seal interior airflow leaks.

Because warm air rises, changing the direction of warm airflow away from the roof reduces ice damming. Apply insulating form to any gaps around vent pipes.

  • Utilize deicing cables.

Installing deicing cables directly over roof shingles or near eaves often prevents ice dams from forming. They are relatively inexpensive and easy to install.

At O’LYN Roofing, we have over 40 years of knowledge and experience working with homeowners to prevent ice dams. We specialize in roofing in the Greater Boston Area, including gutters and skylights. For all your roofing needs, trust us to deliver the right solution. Contact us today to schedule a free initial consultation.