Ice Dam Prevention This Winter

If this winter feels unpredictable, you’re not wrong. We’ve been experiencing a familiar but frustrating pattern: cold temperatures and snow followed by milder daytime weather, then freezing again overnight. That constant freeze-thaw cycle is the perfect recipe for ice dams, even in years when snowfall totals are relatively modest.

Ice dams form when snow accumulates on a roof and begins to melt during warmer daytime temperatures. Heat escaping from the home, often through an under-insulated attic, warms sections of the roof just enough to melt the snow. The water then runs down toward the eaves and gutters, where roof temperatures are colder. As nighttime temperatures drop, that water refreezes. When this melting and refreezing happens repeatedly, a thick ridge of ice builds up along the roof edge, creating an ice dam.

These icy barriers don’t just sit harmlessly at the edge of your roof. They block proper drainage, forcing melting snow to back up under shingles. That water can seep into the attic, soak insulation, stain ceilings, damage walls, and create conditions that encourage mold growth. The weight of the ice itself can also pull gutters away from the house or loosen shingles, opening the door to even more water damage.

Homeowners should watch for early warning signs. Large icicles hanging from gutters, uneven snow melt across the roof, or water stains appearing on interior walls during winter are all indicators that heat is escaping and ice dams may be forming.

When ice dams appear, many homeowners are tempted to take matters into their own hands, but this is where things often go wrong. One of the most common mistakes is hacking away at ice with a shovel, axe, or ice chopper. While it may feel productive in the moment, this can easily damage shingles, puncture the roof, or dent gutters, leading to repairs that cost far more than the ice dam ever would have. Another risky approach is climbing onto an icy roof without proper safety equipment. Slips and falls are a serious hazard during winter and can result in severe injury.

Chemical deicers can also cause problems if used improperly. Products not designed specifically for roofs may damage shingles, kill nearby landscaping, or corrode metal gutters. Even roof-safe deicing products should be used cautiously and viewed as a temporary measure, not a long-term solution.

The real fix for ice dams isn’t on the roof at all. It starts in the attic. Proper insulation and ventilation help keep roof temperatures consistent, preventing snow from melting unevenly in the first place. Unfortunately, more than 75% of New England homes are under-insulated, often because they were built before modern energy standards were in place. As a result, heat escapes easily, setting the stage for ice dam formation.

Improving insulation helps keep warm air inside the living space where it belongs, while proper ventilation allows cold air to circulate in the attic and keeps the roof surface cold. Together, these upgrades not only reduce the risk of ice dams but also improve comfort year-round and lower energy bills. They can also help reduce moisture buildup in the attic, decreasing the likelihood of mold and mildew.

With today’s increasingly unpredictable winter weather, ice dams are no longer just a problem after major snowstorms. Repeated freeze-thaw cycles mean they can form quickly and unexpectedly. Addressing insulation and ventilation now, before damage occurs, is one of the smartest investments a homeowner can make.

Bob O’Donnell is the owner of O’Donnell Bros, Inc., a Bristol-based home improvement company established in 1975. Email your questions for Bob to info@odonnellbros.com with the subject line “Ask the Pro.” All questions may be considered for publication. To contact Bob for your remodeling needs, call O’Donnell Bros, Inc. at (860) 589-5155 or visit www.odonnellbros.com. Advice is for guidance only.