Who, What, Where, When? Who: Roof ice and ice dams result from heat escaping from the attic or space in the roof. This heat builds up and melts snow that is built up on the roof. The water then runs along the cold edge of the roof and forms an ice dam once it freezes. Ventilation, insulation, solar orientation, tree coverage, home architecture, snow cover, and weather conditions are all factors that can cause ice dams on the roof of a home. All houses are different in style,