Princeton — Ice Dam Remediation

Princeton averages 51 inches of snow per season, and the Mille Lacs County winter runs roughly November 15 through March 15 with extended cold snaps that drop to -25°F or colder. Ice dams form when heat escaping through an insufficiently insulated and ventilated attic warms the roof deck, melts the snowpack above, and that meltwater refreezes at the cold eave overhang. The result is a dam of ice at the drip edge that backs water under the shingles — sometimes six to eight feet up the slope — and into the wall cavity.

This split-entry in a Princeton neighborhood near the Rum River had been showing water stains on the first-floor bedroom ceiling for two winters. The homeowners had paid to have ice dams chipped off manually the previous January, which damaged two courses of shingles and accomplished nothing permanent.

We came in February of the second winter. First step was low-pressure steam removal — not chipping, not salt tablets, not hot water. Steam releases ice dams without impact damage to the shingles or gutters. Once the eave was clear, we could diagnose the root cause: the attic had R-19 batt insulation with no air barrier at the top plates, and the soffit soffits were blocked by insulation that had been pushed against them during a previous renovation.

The fix was a two-part job. Ventilation side: we installed polystyrene rafter baffles at every rafter bay to restore the soffit-to-ridge airflow channel — 24 baffles across the eave span. We added ridge vent where there had been none and sealed the top-plate air leaks with spray foam. Roofing side: we removed and relaid the first three courses of shingles above each eave, installed ice-and-water shield up six feet from the drip edge, and relaid the shingles. The following winter produced no ice dam, no ceiling stains, no service call.