Ice Dam Removal & Prevention

How an Ice Dam Actually Forms

Warm air escapes from the living space into the attic. That heat warms the roof deck, and the snow sitting on the middle of the roof melts from underneath. The meltwater runs down toward the eaves — which overhang unheated space and stay at outdoor temperature — and refreezes there. Repeat that for a few days and you build a ridge of solid ice at the edge of the roof. Now the next round of meltwater has nowhere to go, so it pools behind the dam and works backwards under the shingles, which are designed to shed water downhill, not hold it. From there it is into the sheathing, the insulation, the wall cavity and the ceiling.

Removal — Done Safely

Never chip an ice dam off with a hammer, an axe or a garden shovel. You will damage the shingles underneath, and you will very likely fall. Salt and de-icing chemicals corrode metal flashing and gutters and kill the plantings below. We remove ice dams with low-pressure steam, which melts through the ice without touching the roof surface, and we clear the gutter and downspout line so meltwater has somewhere to go.

Prevention — So It Does Not Come Back

• Air-sealing the attic floor to stop warm air leaking up in the first place
• Correcting attic insulation depth and coverage
• Balancing intake ventilation at the soffits with exhaust at the ridge, so the attic runs cold
• Insulation baffles so blown-in insulation is not choking the soffit intake
• Ice & water shield membrane at the eaves during any re-roof — the last line of defence
• Gutter and downspout capacity that actually clears meltwater
• Correcting bath and dryer vents that discharge into the attic instead of outside