Snowmelt changes how water reaches the roof
An ice dam forms when meltwater reaches a colder roof edge and refreezes. Additional water can back up behind that ice. However, ice at the eave does not prove the exact source of every interior drip.
Wind-driven snow can also enter vents or small openings, remain hidden, and melt later. Attic frost can produce similar delayed dripping when temperatures rise.
Clues that help separate the possibilities
- Water at exterior walls or eaves during a thaw
- Frost or staining on roof decking and fasteners in the attic
- Blocked soffit intake or compressed insulation at the eaves
- Leaks near valleys, skylights, chimneys, or roof-wall transitions
- Symptoms that occur without rain but after accumulated snow
- Warm-air leaks around attic hatches, lights, ducts, or exhaust fans
What a complete evaluation may include
The roofing company may need to examine the exterior covering and flashings together with accessible attic conditions. Depending on the finding, roofing, air sealing, insulation, ventilation, electrical, mechanical exhaust, or water-mitigation work may involve different qualified professionals.
Removing visible ice may reduce an immediate hazard, but it does not automatically correct the heat and moisture conditions that caused repeated buildup.
Safe next steps
Do not climb onto a snowy or icy roof or stand below falling ice. Document interior symptoms, keep people away from unsafe ceilings or electrical areas, and describe the timing and weather conditions when requesting help.
Why repeated winter leaks need more than an exterior patch
When heat and moisture from the building contribute to melt or attic frost, an exterior patch can leave the underlying condition unchanged. Conversely, adding insulation or vents will not repair missing flashing or damaged roofing. The diagnosis must connect the observed water to the building assembly.
Ask for observations that support the recommendation: where ice forms, attic staining or frost patterns, exhaust termination, eave conditions, roof penetrations, and the relationship between outdoor temperature and the leak.
Information to include in the request
- How much snow was on the roof
- Whether ice was visible at the eaves or in a valley
- Whether the leak began during warming, rain-on-snow, or a deep freeze
- Indoor humidity or recent moisture-producing activity
- Where attic frost or wet insulation was observed
- Whether the same location leaked in prior winters
Why this leak has almost nothing to do with the covering
This is why a roof three years old can leak during a thaw while performing perfectly in summer rain. Nothing has failed. The roof is being asked to do something it was never built to do, and the cause sits in the attic rather than on the roof.
The practical consequence is that money spent on the covering does not solve it. A replacement can add ice-protection membrane, which stops the backed-up water entering the building — genuinely valuable — but the dam still forms every winter until the attic changes.
Separating the three winter water sources
| What you observe | Which of the three it is |
|---|---|
| Water during a thaw, at an outside wall or ceiling edge | Ice damming |
| Frost on sheathing, dripping in cold dry weather | Attic condensation |
| Water during winter rain, unrelated to snowpack | An ordinary roof leak that happens to be winter |
| Staining that appears every winter in the same place | Ice damming, almost certainly |
| Water inside with icicles but no ridge of ice behind them | Possibly gutter ice rather than a dam — still worth checking the attic |
Primary sources
Published August 12, 2026 and last reviewed August 16, 2026 by Greater Burlington Roofing. General roofing information; an on-site inspection is required for property-specific recommendations.