Ice dams across Park City & the Wasatch Back: stop the ridge before it forms

The physics, in one paragraph

Heat escaping through the roof melts the snowpack from below; the water runs down to the cold overhang and refreezes into a ridge, the dam. New melt pools behind it, and pooled water on a roof does what water does: finds the nail holes and laps under shingles, which shed running water but don’t seal against standing water. The stain shows up on a ceiling or wall top plate, often far from the actual entry.

What an ice dam does to a house

The dam itself is ice; the damage is a slow interior water loss that runs every warm afternoon and refreezes every night, often for weeks before anyone notices.

• Soaked attic insulation that loses its R-value, which makes the roof warmer and the dam worse
• Ceiling and wall staining, sagging drywall, peeling paint and trim, often rooms away from the eave
• Water inside wall cavities, where mold’s roughly 48-hour clock starts running unseen
• Cupped and warped hardwood along exterior walls
• Rotting roof deck, fascia, and soffit from repeat winters of the same leak path
• Gutters and heat cable torn loose by the sheer weight of the ice

Prevention is an attic project, not a roof project

• Air-seal the attic floor first. Can lights, bath fans, chases, the attic hatch, warm-air leaks melt snow in stripes you can see from the street.
• Insulate to altitude: R-49+ up here. Uneven depth shows up as uneven roof snow, your roof is a diagnostic photo after every storm.
• Ventilate the deck cold: clear soffit intakes and ridge exhaust keep the roof surface near outdoor temp so melt happens at the sun’s pace, not the furnace’s.
• Heat cable where architecture wins: complex rooflines, dead valleys, and north eaves sometimes need it, install before the season and test it each fall.
• Roof-rake the first six feet after big storms on problem eaves, no snow at the eave, no dam. From the ground, never on a ladder over ice.

If water is already coming in

Catch drips, move contents, and resist the urge to chip the dam, hatchets kill shingles and occasionally people. We trace the entry path with thermal imaging, dry the cavity before mold’s 48-hour clock runs, and document the cause: ice-dam interior damage is generally covered on Utah policies, and the file we build is what keeps it uncontested. The full response runs like any water intrusion; historic Old Town plaster gets the preservation-first treatment.