Ice dam on the edge of a roof. Ice dams can form when insufficient insulation causes melting of now which refreezes at the eaves as ice. The ice dam holds back pooled melt water which can leak into the house and cause damage.

Ice dam on the edge of a roof. Ice dams can form when insufficient insulation causes melting of now which refreezes at the eaves as ice. The ice dam holds back pooled melt water which can leak into the house and cause damage.