Ice Dams: Causes, Prevention, and Roof Repair Questions for 2026

What an ice dam is

An ice dam is a ridge of ice near the eave that can impede meltwater drainage. Water may back up beneath roofing materials and enter the building. The roof covering alone may not solve the conditions that create uneven roof temperatures.

What to do during an active leak

Move valuables, capture water safely, and document visible interior and exterior conditions. Do not climb onto an icy roof or chip ice with tools that can damage shingles or injure someone. If structural sagging or electrical hazards appear, leave the area and contact appropriate emergency professionals.

Prevention is a building-system issue

A building professional can assess air leakage from the living space into the attic, insulation depth and continuity, ventilation design, and roof details. Local climate and code requirements matter. Ice-and-water membrane at eaves may be required in some locations, but it does not correct every attic heat-loss problem. Ask the roofer to explain the full approach.

Questions to ask

• Where is heat entering the attic, and how will air leaks be sealed?
• Is insulation continuous and appropriate for the climate zone?
• Are intake and exhaust ventilation balanced and unobstructed?
• What eave protection does local code require?
• Are gutters or drainage contributing to the issue?

Avoid adding attic fans or blocking ventilation without professional advice; changes can create moisture or combustion-safety issues. For replacement planning, use the roof replacement cost calculator; for contractor questions see contractor guides.