Ice dams are among the most consistently misdiagnosed home problems in Eastern Washington. They present as a roof leak, so homeowners call a roofer, and a roofer who replaces the covering without addressing the cause has sold a repeat performance.
What is actually happening
Heat escapes from the living space into the attic. That heat warms the roof deck. Snow sitting on the warm part of the deck melts from underneath. The meltwater runs down the slope until it reaches the eave — which overhangs unheated space and is therefore cold — and refreezes there.
That refrozen ridge grows. Behind it, meltwater backs up. Shingles are designed to shed water flowing downhill, not to hold standing water, so it finds its way under the courses and into the structure.
The leak appears inside. The cause is in the attic.
Why replacing the roof does not fix it
A new roof covering does not change the temperature of the roof deck. The heat is still escaping, the snow still melts from below, the meltwater still refreezes at the cold eave.
A quality installation with proper ice and water membrane at the eaves will handle the backed-up water better and prevent the leak. That is genuinely valuable and worth having. But it manages the symptom rather than removing the cause, and the ice dam still forms.
The actual fix
Air sealing. The first and most important step, and the one most often skipped. Warm air leaks into the attic through gaps around light fittings, plumbing penetrations, the attic hatch, chimney chases and top plates. Sealing those is more effective than adding insulation on top of a leaky ceiling.
Insulation. Adequate depth, evenly distributed, with no gaps or compressed areas. Compressed insulation performs far below its rating, and insulation shoved aside during previous work is common.
Ventilation. Soffit vents drawing cold air in at the eaves and ridge or roof vents exhausting at the top, keeping the roof deck close to outdoor temperature. Blocked soffit vents — frequently blocked by insulation pushed into them — defeat the whole arrangement.
Together these keep the roof deck cold, and a cold deck does not melt snow from beneath.
Where to look for the heat leak
Recessed lights are a common culprit, since older fittings are effectively holes in the ceiling. The attic hatch, if it is uninsulated and unsealed. Bathroom extractor ducts, particularly if they terminate in the attic rather than outside — which pushes warm humid air directly into the space you are trying to keep cold.
That last one causes two problems at once: it feeds the ice dam and it condenses against cold roof structure.
Roof rakes and short-term measures
Removing snow from the lower few feet of roof with a roof rake, from the ground, reduces the material available to form a dam. It is a genuine short-term mitigation.
What to avoid: chipping at ice with anything sharp, which damages shingles, and getting on an icy roof, which is how people get seriously hurt.
Getting an honest assessment
If a contractor proposes replacing your roof to solve ice dams without discussing attic insulation and ventilation, get a second opinion. The roof may genuinely need replacing for its own reasons, but that is a separate conversation from why you are getting ice dams.
Good practice is to look in the attic. A contractor who has not been up there is guessing at the cause.