How an ice dam forms on a Reno roof
An ice dam is not caused by snow. It is caused by uneven roof temperature. Heat escaping from the house into the attic warms the upper roof deck enough to melt the snow sitting on it; the meltwater runs down to the eave, which hangs past the heated structure and stays below freezing, and refreezes there. Each melt-refreeze cycle adds a layer, until a ridge of ice forms along the edge. Water arriving behind that ridge has nowhere to go but up — under the shingles, through the underlayment, and into the wall or ceiling below.
Reno is built for this. The area averages about 20.9 inches of snow a year, and roughly three-quarters of it falls December through February (NOAA 1991–2020 normals, the same figures on our snow-load and elevation guide). A high-desert winter also swings hard between bright, above-freezing afternoons and sub-freezing nights, so a roof can run several melt-refreeze cycles in a single week without any new snow at all. North-facing eaves, shaded valleys, and the roof above a poorly insulated cathedral ceiling or a heated garage are the usual starting points.
What an ice dam looks like from the ground
- A band of ice along the eave while the upper roof is bare or lightly covered — the tell-tale pattern. Snow on the whole roof is fine; snow only at the edge means the top is melting.
- Large icicles hanging from the gutter line, especially in one stretch of eave rather than evenly.
- Ice in or behind the gutter, or a gutter visibly pulling away from the fascia under the weight.
- Water stains on the ceiling near an exterior wall, a wet patch at the top of a wall, or peeling paint at the eave soffit — the leak has already started.
What professional ice dam removal costs
Removal is priced by time and method. Steam is the industry standard because low-pressure steam cuts channels through the ice without touching the shingles; pressure washing and manual chipping are cheaper and faster but carry real risk of tearing granules off or cracking cold, brittle shingles.
| Item | National cost | Note |
|---|---|---|
| Professional removal, typical | $650–$2,400 (avg ≈ $1,200) | Full spread $400–$4,000 |
| Labor rate | $150–$700 per hour | Two-hour minimum is common |
| Steam removal | $800–$2,400 | Safest for shingles; the method to ask for |
| Manual chipping / roof raking | $800–$1,800 | Risk of shingle damage on a cold roof |
| Pressure washer | $400–$2,000 | Can strip granules; ask before agreeing |
| Chemical (calcium chloride tablets or salt) | $200–$400 | Opens a drainage channel; does not remove the dam |
| Roof snow removal (preventive) | $200–$700 | Before a dam forms, after a big storm |
| Emergency / after-hours | Premium applies | No published figure — ask when you call |
Methodology: Angi, "How Much Does Ice Dam Removal Cost?", updated 2026-07-09 (national); no Reno/Sparks-specific ice-dam pricing published as of 2026-10-20. Reno labor rates sit near the national middle for most roofing work, but a winter emergency in a market with a short snow season can price above it — get the rate and the method in writing before the crew climbs the ladder. Any repair that follows is priced separately; our roof repair guide carries the leak and flashing figures, and this page deliberately does not restate them.
What not to do
- Do not get on the roof. A snow- or ice-covered roof is the most dangerous surface on the property. Everything useful a homeowner can do is done from the ground.
- Do not chip, hammer, or hack at the dam. Cold asphalt shingles are brittle; a hatchet or ice pick on the eave turns a water problem into a re-roof-the-edge problem.
- Do not use rock salt. Sodium chloride corrodes aluminum gutters and fasteners and kills the landscaping below the downspout. If you use a de-icer, use calcium chloride, and use it sparingly.
- Do not aim a torch or hot water at it. Open flame near a roof edge is obvious; hot water refreezes into a bigger dam before it drains.
After the dam is gone: the repair conversation
Removal stops the water. It does not fix what the water did. Once the eave is clear, a roofer should lift the bottom courses of shingle to check the underlayment and decking for saturation, look at the fascia and gutter hangers, and go into the attic to check the insulation directly below the eave — wet insulation stops insulating, which makes next year's dam more likely. The repair guide walks through what an eave leak repair involves and what it costs, and the inspection page covers what a post-winter check should include.
Before any repair work is authorized, photograph the dam, the icicles, and every interior stain, and call your insurer. Whether a policy covers ice-dam water damage depends on the policy and on how the damage is classified — we cannot tell you what yours will do, but the adjuster will want dated photos and separate invoices for removal and repair. Nevada also caps a contractor's deposit at the lesser of $1,000 or 10% of the contract (NRS 624.970), so nobody should be asking for the repair money up front in the middle of a storm.
Prevention, in the order that actually works
- Stop the heat loss. The dam exists because the attic is warmer than the outside air. Air-sealing the ceiling plane (recessed lights, bath fans, the attic hatch, plumbing penetrations) and bringing attic insulation up to current depth does more than any roof-side fix. Priced by an insulation contractor, not a roofer — ask for an attic assessment that includes a look at ventilation.
- Ventilate the attic. Continuous soffit intake and ridge exhaust keep the roof deck close to outdoor temperature so the snow on it stops melting from below. Blocked soffit vents — usually buried under insulation — are a common finding on older Reno and Sparks homes.
- Ice-barrier underlayment at the next re-roof. A self-adhering membrane at the eaves that stops backed-up meltwater from reaching the deck. Washoe County requires it above 5,300 feet; below that line it is an option worth taking on any north-facing or shaded eave. It cannot be retrofitted without lifting shingles, so the time to specify it is when you are already replacing the roof — see the replacement cost guide and snow-load guide.
- Keep the eave clear. Clean gutters before the first snow ($75–$400 nationally) so meltwater has somewhere to go, and pull snow off the lower few feet of roof with a roof rake after a heavy storm. Gutters do not cause ice dams — heat loss does — but a gutter packed with ice and debris holds the backed-up water exactly where it does the most damage. The seasonal maintenance checklist has the fall and winter steps.
- Heat cable, last. Self-regulating cable zig-zagged along the eave and down the valleys keeps a drainage channel open. Installed cost runs $500–$4,600 nationally and it uses power every cold night, so it is the right answer for a specific stubborn eave, not a substitute for fixing the attic. Snow guards ($500–$10,000) are a different product for a different problem — holding snow on a metal roof so it does not slide — and do not prevent ice dams.
When to call a roofer instead of waiting for a thaw
- Water is actively dripping or staining inside — every hour it runs is more wet insulation and drywall. The emergency roof repair page covers what the first visit should include.
- The ice at the eave is more than a few inches thick, or the gutter is sagging under it.
- The dam sits above a living space with a cathedral ceiling, where there is no attic to absorb the leak.
- You have had one on the same stretch of eave two winters running — that is a heat-loss diagnosis, not a weather event.
Before you hire, ask for the NSCB license number and the removal method in writing, and verify the license yourself — our license lookup guide shows how. Serving Reno and Sparks, Nevada.