Ice dam on roof
moderate 1–2 h
Tools: roof rake with an extension pole, box fan (attic), flashlight · Materials: calcium chloride ice-melt in a nylon stocking, attic insulation and air-sealing foam (the real fix)
Steps
- From the ground, pull snow off the lower metre of the roof with a roof rake after each snowfall — no snow, no meltwater, no dam.
- If a dam has formed and water is coming in, lay a stocking filled with calcium chloride across the dam so it melts a channel; never chip ice with tools.
- In the attic, point a box fan at the underside of the wet area to refreeze the leak temporarily.
- Once thawed, find the warm spots: gaps around attic hatches, recessed lights, bathroom fans venting into the attic, and thin insulation all heat the roof deck.
- Air-seal those leaks with foam and top the insulation up to your climate's recommended depth before next winter.
Stop and call a pro if
- you would need to climb onto an icy roof
- water is coming through in several places or the ceiling is sagging
- the roof is above one storey and the rake cannot reach
What a pro does that you can't
A roofer steams dams off safely, and an insulation contractor air-seals and insulates the attic and adds ventilation — the only permanent fix.
DIY cost: $30–80 for a roof rake and ice-melt