Every winter, homeowners across Manchester, Concord, and the Lakes Region face one of New England’s most destructive winter roof hazards: ice dams. These heavy ridges of ice form along the eaves of your roof, preventing melting snow from draining off into your gutters.

When melted water backs up behind the ice dam, it works its way under your shingles, seeping into attic insulation, exterior walls, and ceiling drywall. By the time you notice ceiling stains inside, thousands of dollars in water damage may already have occurred.

What Causes Ice Dams to Form?

Contrary to popular belief, ice dams are not caused by heavy snowfall alone. They are created by an imbalance in your roof’s surface temperature. Here is the three-step science behind how an ice dam builds up:

  1. Warm Attic Air: Heat leaks from your heated living space into an uninsulated attic, warming the underside of the roof deck.
  2. Snow Melt: Snow on the upper section of the warm roof deck melts and trickles down toward the eaves.
  3. Refreezing: When the meltwater reaches the cold overhang (the eaves/gutters overhang outside your home’s exterior walls), it freezes into ice. Over days, this ice accumulates into a solid wall.
“An ice dam isn’t a roofing material failure — it is a thermal management failure. Stopping warm air from escaping into your attic is 90% of the battle.”

3 Long-Term Solutions to Prevent Ice Dams

1. Upgrade Attic Insulation and Seal Air Leaks

The most effective long-term defense against ice dams is keeping your attic space as cold as the outside air temperature. You can achieve this by sealing attic floor bypasses around recessed lighting, chimney flues, and drop ceilings, then increasing attic insulation to at least R-49 to R-60 standards</strong > suitable for New Hampshire winters.

2. Ensure Balanced Ridge & Soffit Ventilation

Adequate ventilation allows cold air to enter through soffit vents at the eaves and exhaust warm air out through continuous ridge vents at the peak. This continuous airflow carries away trapped heat and moisture before it can warm the roof deck.

💡 Pro Tip for NH Homeowners

Never rake snow off your roof while standing on a tall ladder. Using a roof rake with an extendable pole safely from the ground is acceptable, but ensure you leave a thin layer of snow to avoid damaging shingle granules.

3. Install Ice & Water Shield Underlayment During Re-Roofing

If your roof is reaching the end of its lifespan, replacing it gives you the opportunity to install a rubberized, self-sealing Ice & Water Shield membrane along all eaves, valleys, and chimney flashing. In New Hampshire, local building codes mandate extending this shield at least 24 inches inside the interior warm wall line.

What to Do If You Currently Have an Ice Dam

If you suspect an active ice dam is causing an interior leak right now:

  • Avoid hammers and hatchets: Chipping away at frozen ice dams with sharp tools will puncture shingles and exacerbate leaks.
  • Do not use rock salt: Throwing standard calcium chloride or rock salt onto shingles bleeds chemicals into landscaping and degrades asphalt shingle fasteners.
  • Call for professional steam removal: Professional roofers use low-pressure industrial steamers to safely slice through ice dams without damaging shingle layers.

Have questions about your roof’s winter readiness? Contact Vincenzo’s Roofing today for a complimentary 21-point roof and attic ventilation inspection before severe weather hits.